Comprehensive Assessment of Heavy Slow Resistance Training and High-Dose Therapeutic Ultrasound in Managing Patellar Tendinopathy

Comprehensive Assessment of Heavy Slow Resistance Training and High-Dose Therapeutic Ultrasound in Managing Patellar Tendinopathy | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Comprehensive Assessment of Heavy Slow Resistance Training and High-Dose Therapeutic Ultrasound in Managing Patellar Tendinopathy Liufeng Xiao, Heng Zhou, Jia He, Hua Liu, Yongchao Li, Ziyi Liu, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4602813/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Oct, 2024 Read the published version in BMC Sports Science, Medicine and Rehabilitation → Version 1 posted 4 You are reading this latest preprint version Abstract Background: Patellar tendinopathy (PT) is a common sports-related injury that often recurs. Heavy Slow Resistance Training (HSR) and High-Dose Therapeutic Ultrasound (TUS) are commonly used to treat PT. However, there is a lack of research on the combined effectiveness of these treatments. Methods: In this study, fifty-one college students aged 18 to 25, diagnosed with patellar tendinopathy using musculoskeletal ultrasound, were randomly assigned to three groups: a Combined HSR and high-dose TUS treatment group (n=17), an HSR training group (n=17), and a high-dose TUS treatment group (n=17). The intervention lasted for 8 weeks and various assessments were conducted including the Victorian Institute of Sport Assessment-Patella (VISA-P), Visual Analogue Scale (VAS), Y-balance Test (YBT), Modified Thomas Test (MTT), Horizontal Jumping Distance, Maximum Isometric Muscle Strength Test, musculoskeletal ultrasound for patellar tendon thickness and blood flow, and electromyography (EMG) of lower extremity muscles. Results showed significant improvement in knee joint function across all intervention methods, with the Combined group showing the most improvement. Follow-up at week 16 indicated continued improvement in VISA-P scores for the Combined and HSR groups, while a decrease was observed in the TUS group. Compared to pre-intervention, all groups showed significant differences in post-intervention VAS scores (p < 0.01), indicating a reduction in pain. While no significant differences in VAS scores were present among groups pre-intervention, post-intervention results revealed significant differences between the Combined and HSR groups (p < 0.05), as well as between the Combined and TUS groups (p < 0.01). The MTT test demonstrated notable improvements in joint mobility and quadriceps flexibility in the Combined and HSR groups after the 8-week intervention (p < 0.01), with no significant changes observed in the TUS group. Inter-group comparisons did not show significant differences both before and after the intervention. YBT test results also indicated significant differences. Conclusion: Both exercise intervention and high-dose TUS can moderately decrease pain and improve motor capacity in patients with patellar tendinopathy. However, the therapeutic effect of high-dose TUS alone is relatively limited compared to exercise intervention. The combined application of both methods results in the most significant improvement in pain relief and motor function enhancement. The trial was registered on ISRCTN11447397 (www.ISRCTN.com) on 17/02/2024（Retrospectively registered）. patellar tendinopathy heavy slow resistance therapeutic ultrasound efficiency exercise Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Patellar tendinopathy (PT) is a common chronic sports injury characterized by significant pain in the proximal patellar tendon( 1 ). Patients with this condition often experience tenderness in the patellar tendon area, as well as a decrease in strength and mobility in the surrounding region( 2 ). A study published in the 2020 British Journal of Sports Medicine highlighted that individuals with PT frequently face persistent pain and functional limitations, particularly during weight-bearing activities or those involving significant impact forces( 1 ). T Symptoms typically worsen post-activity, and PT is frequently observed in sports that require high levels of speed and strength, such as volleyball and basketball, which heavily engage the leg extensor muscles( 3 ). Research has shown that approximately 52.3% of basketball players suffer from PT, leading to a noticeable decline in their athletic performance( 4 ). PT tends to persist as a long-term issue, posing challenges for effective management without intervention( 5 ). Current treatment approaches for PT encompass a combination of passive and active modalities( 6 ). Passive treatments include options like medication, injections, extracorporeal shockwave therapy (ESWT), ultrasound, and low-intensity lasers. Active treatments involve strategies such as tendon loading training (TLT)( 7 ),HSR training( 8 ) and eccentric exercise training(ECC) ( 9 ) etc. Therapeutic ultrasound (TUS) is a frequently employed therapeutic modality in the field of physical therapy( 10 ). Many studies have explored the effectiveness of therapeutic ultrasound in treating PT, with favorable results reported in certain cases. ( 11 , 12 ). TUS has been shown to stimulate the self-repair mechanism of the patellar tendon, increase its temperature, raise the pain threshold, and promote collagen elongation. Additionally, high-dose TUS can influence the tissue structure of the patellar tendon, facilitating improved energy absorption and dispersion, thereby enhancing knee joint function in patients with PT, research has indicated that both high-dose and low-dose TUS can ameliorate PT, with high-dose TUS demonstrating greater effectiveness( 13 , 14 ). HSR training, including exercises like barbell squats and deadlifts, has been demonstrated to induce localized hypertrophy and enhance the mechanical chattels of the patellar tendon region ( 15 , 16 ). HSR training focuses on stabilizing the centrifugal and centripetal phases of the loading movement, which enhances the subject's neurological adaptations as well as greater strength variability, and is effective in improving tendon swelling and vascularization( 17 , 18 ). As a therapeutic strategy for individuals with patellar tendon pain and to improve knee extensor strength, HSR training can be utilized( 8 , 19 ). The objective of this study was to assess the effects of HSR training on individuals with PT. We conducted HSR training and/or therapeutic ultrasound interventions on young athletes with PT to explore the therapeutic outcomes of these various physiotherapy approaches. Our goal was to establish a theoretical foundation for more effective PT treatments. 2. Methods DESIGN: This study was designed as a single-blind, randomized controlled trial. Subjects, imaging physicians, and experimental data collectors were blinded. The participants were randomly assigned to groups using the envelope method. The objective was to assess the effectiveness of HSR therapy in combination with high-dose therapeutic ultrasound and combined therapy for patellar tendinopathy by comparing pre- and post-intervention data. We implemented rigorous experimental protocols, limiting the study to the Sports Intervention Center of Wuhan Sports University, employing a consistent experimental site, and enlisting a highly trained therapist. As a result, the confidence level in the experiment's validity was significantly elevated. 2.1 Subjects From October 2022 to May 2023, 53 college students with chronic patellar tendinopathy in the age range of 18 to 24 years old, including 46 males and 5 females, were recruited at Wuhan Sports University, and the subjects were centrally intervened for a period of 8 weeks (diagnosed by an orthopedic deputy chief physician with 15 years of clinical experience. The subjects were identified as having chronic patellar tendinopathy only if the duration of pain was greater than three months.(20) The diagnosis was supported by ultrasonography. Diagnosis was supplemented with ultrasound imaging to leave out patellofemoral pain syndrome (PFPS) based on a patellofemoral pain statement(21). Table 2 shows the rudimentary features of the subjects. The criteria for subject inclusion in the experiment were 1. Subjects with a VISA-P questionnaire score of <80 out of 100(22, 23),2. history of patellar tendon pain related to training or competition, 3. structural changes in the patellar tendon on gray-scale ultrasound and/or increased tendon vascular distribution on energy Doppler(24),4. significant tenderness on palpation near the end of the patellar tendon and pain limited to the inferior level of the patella(25) 5. pain aggravated by squatting or jumping. Ultrasonography was performed by a 15-year-experienced sonographer, and was positive for the presence of patellar tendon structural changes and/or hypoechoic changes and/or thickening of the patellar tendon (anterior-posterior diameter >6 mm) and/or increased intratendinous Doppler flow(26).All subjects signed a written informed consent before the start of the experiment. Subjects will be excluded on the basis of 1. duration of pain less than three months, 2. acute knee or patellar tendon injury with a history of knee surgery in the past year, 3. presence of inflammatory arthropathy with use of potentially affecting patellar tendon medications (e.g., quinolones) in the past year, 4. use of corticosteroids for topical injections in the past month, 5. history of past patellar tendon rupture, 6. failure to perform a training program or participate in other treatment programs 7. Exercise program, or participation in another treatment program, physical examination or ultrasound/MRI findings of other coexisting knee pathology, 8. Inability to undergo high-energy does ultrasound therapy or indications that ultrasound is contraindicated such as (active tuberculosis, bleeding tendency, severe cardiac disease, malignant tumors, venous thrombosis, and pregnant women). Each subject was informed of the procedure before the start of the experiment and gave a paper informed consent form. All data from the subjects were authorized. Figure 1 shows the flow chart with the summary experimental procedures and the situation of participants, according to the Consolidated Standards of Reporting Trials (CONSORT)(27). 2.2 Blinding and randomization Before initiating the study, all participants were familiarized with the research procedures following a baseline assessment. After including subjects who met the required criteria, baseline data were collected to minimize potential data interference. It is important to note that non-research team members collected the baseline data. It is important to note that non-research team members collected the baseline data. Allocation concealment was ensured by an experimenter (L.Z.Y.), who did not participate in follow-up data collection. Subsequently, L.Z.Y recorded the groupings on paper and sealed them in an opaque envelope. The envelope was handed to the subject; upon completing baseline data collection, the subject returned the envelope to the interventionist, who then administered the corresponding group intervention. Subjects remained unaware of their group assignments. The study required that subjects not discuss any exercise regimens or therapeutic measures during the study period. The intervention was supervised by two therapists (HJ, NX), who were not involved in the group assignment. The imaging physician remained blinded during the outcome data collection. 3. Interventions 3.1. HSR Training Heavy slow resistance training methods, as demonstrated by Kongsgaard (8) , , involved intervention protocols with symmetrical loading on both legs. Despite this, subjects may have altered their center of gravity as a result of pain in the affected leg. Furthermore, a significant number of subjects reported experiencing symptoms primarily in one leg, indicating potential benefits of one-legged training. In order to enhance the training impact, one of the Hacker squats was substituted with the Bulgarian Deep Squat. (Figure 2). The training protocol follows NSCA-CSCS standards, emphasizing low bar position barbell squats. Proper form is crucial, with instructions to maintain a straight back, elevate elbow joints, bend hips and knees, and squat slowly until reaching a 90°knee angle. Consistent and stable movement without compensation is essential throughout the training. For the Bulgarian Deep Squat, the subject positions themselves in front of a bench or similar surface, about two feet away, with their back facing the surface. One leg is extended back with toes resting on the bench, ensuring the front foot is positioned far enough to maintain proper alignment during the squat. The subject then lowers until the knee reaches a 90-degree angle, maintaining perpendicular alignment with the surface. Three training sessions were conducted weekly, with bilateral movements on the body and a 2-minute rest between sets. The repetitions/load intensity varied from 12RM in the first two weeks, 10RM in the third and fourth weeks, 8RM in the fifth and sixth weeks, and 6RM in the seventh and eighth weeks. Subjects followed a metronome, spending 3 seconds on both the centrifugal and centripetal phases of the movement (totaling 6 seconds for each movement). To enhance the mechanical properties of the tendon and facilitate adaptations, Morrison et al. (19)recommend a loading protocol with an intensity of >70% 1RM (the weight that can be performed only once for a standard movement) for the lowest resistance training in HSR training. This requires ensuring that subjects perform no more than 12 repetitions. Participants with partial pain (VAS <3) were permitted, as long as pain did not increase in subsequent sessions. A therapist supervised each session to ensure accuracy, completion of training maneuvers, and the safety of the subjects. Each session included a pre-training warm-up and post-training stretching. 3.2. High-dose TUS therapy High-dose TUS therapy was administered to both the combined and TUS groups as part of the intervention. The combined group received this therapy following the completion of their training. High-dose TUS therapy (ULTRASOUND UNIT US-700, Japan) targeted only the patellar tendon region. Full contact was maintained between the subject’s patellar tendon and the high-energy TUS conductor, with gel used as the interface. Throughout the procedure, subjects were positioned supine with a cushion under the knee for immobilization, and the knee was slightly flexed at approximately 20 degrees (14). If subjects exhibited bilateral symptoms, the knee with the more severe symptoms received high-dose TUS treatment. Details on the dosage settings and duration of high-dose TUS are provided in Table1 . 3.3. Combination therapy The combined group followed the same 8-week training regimen as the training group. Each subject completed three weekly training sessions, each consisting of three maneuvers, as depicted in Fig. 1. Participants performed four sets of each maneuver, taking a 2-minute break between sets. Immediately following the training sessions, subjects received high-dose TUS therapy, using identical treatment parameters, duration, and materials as those used in the TUS group. 4. Outcome measure The primary outcome was the VISA-P questionnaire. We used the VISA-P questionnaire to enumerate the level of symptoms and participation in functional activities in PT patients(23) . Higher questionnaire scores were associated with better functioning, with a minimal clinical difference of 13 points(28) . The patients all completed the completed questionnaires autonomously without any assistance after a brief explanation of the questionnaire by the main researcher assistant (HJ). The questionnaire was administered at baseline, 8 weeks and16 weeks. Secondary outcomes were as follows. When subjects exhibited symptoms on both sides, the more severely affected side was selected for inclusion in the test report. To ensure data consistency, the same researcher (L.Y.C.) conducted all data collection. Additionally, at each subsequent test and follow-up, subjects were reminded of their initial selection. Should a subject sustain a physical injury or request to terminate participation at any stage of data collection or training, the experiment was immediately halted. VAS We used a 10-cm Visual analogue scales to evaluate the grade of patellar tendon pain in the subjects, with a score of 0 indicating the absence of any pain and a score of 10 indicating the most severe pain, with higher scores representing more severe pain(29). After a brief questionnaire science was administered to the subjects, the patients were asked to squat on a 25° inclined platform(30), and the patients assessed the degree of patellar tendon pain during squatting using the VAS scale by themselves, during which the evaluator did not provide any kind of guidance to them. The tests were performed before and 8 weeks after the intervention, respectively. Lower Quarter Y Balance Test The Lower Quarter Y Balance Test (YBT-LQ) is an instrument used to evaluate dynamic postural control, which is a variant of the Star Rapids Test (SEBT) that reflects a subject's ability to balance, and whose reliability and validity have been tested(31) . We hypothesized that HSR training would improve subjects' balance ability. The test methodology used was similar to that of Plisky et al.(31) used, but participants were asked to put their hands on the pelvis to exclude the influence of the upper extremities on balance. Participants extended their other leg to push the test board as far as possible in three directions: anterior-lateral, posterior-medial, and posterior-lateral, in order to move the test board to the farthest possible distance (Figure 3) , and then returned to the beginning position after each test, with the foot unable to get in touch with the ground or rely on the test block for support during the test, and the distance of the push was recorded. Each participant performed four experiments with each leg in each direction of extension before the official test, and the participant's performance reached stability(32) The experiment was formally started after a 5-minute rest, and the maximum of the three test results was taken and analyzed. Participants were positioned supine, and their lower limb length—measured from the anterior superior iliac spine to the center of the ipsilateral medial ankle(33) , measured in centimeters. Considering the significant differences in leg length and height of individual subjects, the nudge distance was normalized to the lower limb length of the participant, and the maximum reach distance (%MAXD) was calculated by using the formula (6 farthest distance/length of both lower limbs (a, b) × 3) × 100%MAXD)(34, 35). YBT tests will be measured at baseline and at the end of the intervention. Modified Thomas Test (MTT) Insufficient flexibility and strength in the quadriceps muscle have been identified as potential pathogenic factors in patellar tendinopathy(36). Reduced flexibility of the quadriceps muscle results in a larger knee flexion angle and a slighter hip flexion angle during landing(37), leading to increased loading of the tendon, subsequently inducing degenerative alterations in the patellar tendon. To evaluate quadriceps flexibility, we utilized the modified Thomas test. During this test, participants sat at the end of the treatment bed, bowled backward onto the bed, and curled both knees in front of the chest. It was ensured that the lumbar spine remained flat against the bed and the pelvis maintained a posteriorly rotated position. The subject held the contralateral knee with both arms so that the leg it’s in maximum flexion while relaxing the affected limb and lowering it toward the floor, and the subject's affected knee flexion angle was measured by means of a protractor.(38) (Figure 4) We will compare the change in this angle between baseline and after 8 weeks of training to determine if HSR training enhances quadriceps flexibility in our subjects. Tests were performed once with baseline and once after the 8-week intervention. Maximum isometric strength of lower extremity extensors Subjects underwent testing for isometric maximal strength of the lower extremities using the Leg-Check 626 lower extremity strength stirrup machine (Dr. WOLFF Sports & Prevention GmbH - Bachumer Weg 70 -D 59757 Arnsberg, Germany). Before initiating the test, participants were instructed to adjust the backrest angle. And then to place the legs on the base plate of the device with the knees at 90° (see figure). At the beginning of the test, subjects were told to keep their backs against the backrest, and then to gradually exert their legs to exhaustion in order to avoid transient explosive force interfering with the experiment. Tests were performed once with baseline and once after the 8-week intervention. Horizontal Jump The subjects were tested using the standing long jump tester (Tsinghua Tong fang Electronics, CHINA), the therapist gave a verbal description and demonstration of the test, the subjects were asked to wear non-slip sports shoes. Before the test, participants underwent a 5-minute warm-up session. Following this, they were familiarized with the jumping action before commencing the test procedure. Participants were informed to position behind the jumping line with their feet naturally separated, and with their feet in the original position. Jump forward at the same time, note that there should be no padding or jumping action, each person tested twice, and record the maximum value of the two valid test values. Tests were performed once with baseline and once after the 8-week intervention. The EMG of the muscles of the lower extremities PT has been demonstrated to impact lower extremity kinetics(39) , potentially leading athletes to experience issues during landing(40), affecting the hip joint(39, 40) and ankle joints(40, 41), thereby inducing kinematic alterations. Risk factors for PT include quadriceps strength, flexibility of the posterior thigh muscles, among others(42). Although fewer studies have investigated the effect of training on muscle activation levels in PT patients, we hypothesized that 8 weeks of high-load strength resistance (HSR) training would modulate the activation levels of the vastus medialis oblique (VMO), vastus lateralis oblique (VLO), and biceps femoris (BF) during eccentric squatting on an inclined platform in PT patients. A wireless surface electrode (Noraxon, USA) was used to record the muscle activations of the VMO,VLO,BF at a 1500 Hz sampling rate(43), to analyze the change in muscle activation during single-leg squats on a 25° inclined platform in subjects before and after the intervention. Prior to the start of the movement, all subjects were asked to perform a warm-up preparation activity on a stationary power bike for approximately 10 minutes. All subsequent movement exercises were demonstrated by the therapist (X.L.F) and subjects were ensured to be proficient in the test exercise maneuvers, which started with the determination of three Maximum Voluntary Isometric Contraction (MVIC) of the VMO, VLO, and BF muscles, and required that the duration of each MVIC be maintained above 5s. The duration of each MVIC was required to be kept above 5 s. A 1-minute rest was present between each exercise to facilitate muscle recovery, and the patients were verbally encouraged to strive for the best performance during the test. The subject was instructed to stand on the platform with the affected side (if symptoms were present on both sides, the side with the most severe symptoms was chosen), and then to perform a slow squatting motion until the knee joint reached a 90-degree angle, and after a short stay of 1s, the subject was asked to slowly get up, and the movement was kept at a constant speed throughout. The movement test was performed three times, with a 1-minute rest period between test movements. The raw surface EMG signals were full-wave rectified and then band-pass filtered at a cutoff frequency of 20-400 HZ. In each muscle MVC measured for each athlete, 1s data segments above and below the maximum value of EMG were averaged and thus normalized, and the results were expressed in terms of integral EMG and root mean square (RMS) amplitude.(44). RMS measures the average level of muscle discharge in a muscle over a specific period of time. Tests were performed once with baseline and once after the 8-week intervention. Musculoskeletal ultrasound image Ultrasound procedure: Ultrasound imaging was conducted using a GE LOGIQ E11 ultrasound machine with an acquisition frequency of 9.0 MHZ. The procedure followed the guidelines of the European Society of Musculoskeletal Radiology. Subjects were positioned supine on an examination table with a pillow positioned under the popliteal fossa, maintaining knee flexion at approximately 30°(45).The sensor probe was placed longitudinally over the popliteal fossa. The transducer probe was placed longitudinally in the middle of the patellar tendon, and the probe was kept gently in contact with the skin the whole time without applying any additional pressure on the PT to prevent pressure from affecting the measurement, and the PT thickness was measured 1 cm from the patellar aponeurosis by using the scanner's built-in software(46).Blood flow within the PT was also observed using color Doppler imaging. 5. Statistical analysis The data are presented as means ± SD and range. Statistical analyses were performed using GraphPad Prism Version 9.0.0 and GPower version 3.1.9.4. General data were analyzed using the Kruskal-Wallis ANOVA test. Measurement data were tested for chi-square and confirmed to follow a normal distribution. Paired samples t-tests were conducted within the pre- and post-intervention groups. One-way repeated measures ANOVA by ranks was used to assess differences in values and relative change between groups. In cases of significant differences, a post hoc test was employed to determine significance between groups. All tests were conducted as two-tailed with an alpha level of 0.05. The sample size for this experiment was calculated using GPower3.1 software due to the repeated ANOVA design. An F test was used for sample size calculation with the following parameters: Effect size f = 0.25, α err prob = 0.05, Power (1-B err prob) = 0.8, Number of groups = 3, Number of measurements = 6, Corr among rep measures = 0. The software determined that a minimum sample size of 45 was required for the experiment, with 15 participants in each group. Recruitment has successfully met the minimum sample size requirement for the experiment. 6. Results Primary outcome measure VISA-P A repeated measures ANOVA showed that there was no significant difference in the visa-p scores of the three groups before the intervention (F=2.943, p=0.06), and after the 8-week intervention, there was a significant difference in the between-group comparisons (F=4.974, p=0. 01), and then post hoc multiple comparisons were performed, and the data analyses showed that the scores in the combined group differed significantly from the scores in the TUS group (p=0.008). significant difference (p=0.008). The VISA-P scores included an assessment of the subject's pain symptoms as well as motor function, so based on the results it was learned that the combined group showed greater improvement for PT subjects than the TUS. Secondary outcome measure VAS A repeated measures ANOVA was conducted on the collected VAS scores. The results of the pre-intervention between-group comparison of the VAS scores of the three groups indicated that there was no significant difference (F=0.2215, p=0.82). However, a post-hoc multiple comparisons analysis following the 8-week intervention revealed a significant difference (F=6.97). A post-hoc multiple comparisons test revealed a significant difference between the combined group and the HSR training group (p = 0.048), as well as between the combined group and the TUS treatment group (p = 0.001). This indicates that the combined group demonstrated greater efficacy in reducing the subjects' pain. Furthermore, a paired-samples within-group t-test was conducted on the pre- and post-intervention data for the three groups. The results demonstrated that all three treatments significantly reduced the subjects' VAS scores at the end of the intervention. YBT A repeated measures ANOVA was conducted on the YBT data of the subjects before and after the intervention. The results demonstrated that there was no significant difference in the subjects' YBT test ability between the groups before the intervention (F=2.114, p=0.13). Additionally, there was no significant difference in the comparison of the groups after the 8-week intervention (F=0.8501, p=0.91). Furthermore, a within-group comparison of the three groups of subjects before and after the 8-week intervention using a paired-samples t-test for within-group comparisons revealed a significant difference in the YBT scores of all three groups of subjects before and after the intervention. This indicates that the subjects exhibited some degree of improvement in balance following the intervention, although this was not significant in the between-group comparisons. MTT A one-way repeated measures ANOVA was performed on the collected data from the MTT tests performed on the subjects before and after the 8-week intervention. The results of the between-group comparisons of the three groups of subjects before the intervention revealed no significant difference in MTT before the intervention (F=0.9221, p=0.404). Similarly, the between-group comparisons of the subjects' MTTs after the intervention yielded no significant differences (F=0.888, p=0.433). A second 8-week intervention was conducted, which revealed a significant difference (F= 5.182, p=0.009). A post hoc comparison indicated that the MTT test results of the subjects in the combined group were significantly different from those of the subjects in the TUS group. This indicates that the combination treatment was more effective than the TUS group in improving quadriceps flexibility. A paired-sample t-test was conducted to assess within-group differences in MTT scores before and after the intervention period for the three subject groups. The combined group demonstrated a significant improvement compared to the HSR group after 8 weeks, indicating that both the combined intervention and training regimen demonstrated the potential to enhance quadriceps muscle flexibility in subjects. However, no significant differences were observed between the pre- and post-intervention groups of the TUS group, indicating that the improvement in quadriceps muscle flexibility observed in subjects following TUS treatment was relatively limited. Maximum isometric strength of lower extremity extensors A one-way repeated measures ANOVA was employed to analyze the maximum isometric contraction moments of the lower extremity extensors of the subjects before and after the intervention between groups. The results indicated that there was no significant difference between the pre-intervention groups (F=1.336, p=0.27) and between the post-intervention groups (F=2.739, p=0.07). Subsequent within-group comparisons were made before and after the intervention, using paired samples t-tests. It was concluded that all three intervention modalities significantly improved the maximal isometric contraction strength of the lower extremity extensors, with p-values of <0.0001 in the combined group, 0.0018 in the HSR group, and 0.03 in the TUS group. The improvement was most significant in the combined group Horizontal Jump A comparison of the subjects' pre-intervention and post-intervention data was conducted within and between groups. The results indicated that there was no significant difference between the pre-intervention group comparisons (F=0.2077, p=0.81), and the post-intervention group comparisons were non-significant. A paired samples t-test was employed to conduct within-group comparisons of the subject data, and no significant differences were observed between the three groups before and after the intervention (p = 0.23, 0.95, and 0.77). The EMGS of the muscles of the lower extremities We took the same test as at baseline and observed the changes in the EMG signals of the thigh muscles during the squatting process in the subjects. Seven subjects were unable to complete the posterior side due to conflicting testing schedules: two in the combined group, three in the HSR group, and two in the TUS group. To address variations in individual strength and the time required to complete the maneuver, we utilized the VMO to VLO ratio for pre- and post-comparison of the data, the results showed that compared to baseline, the signals of VMO and VLO were reduced in the three intervention groups , with the VMO/VLO of the combined group being 1.298±0.5491 before intervention and 0.9291±0.1925 after intervention, with significant differences between pre- and post-intervention (P<0.05) while there were no significant differences between pre- and post-intervention for the HSR and TUS groups, see Table 4 .This addition to the three groups there was no significant difference between the groups before and after the intervention. See Figure 5 . Musculoskeletal ultrasound imaging At the end of the 8-week intervention, we measured the thickness of the patellar tendon in the subjects using an ultrasound device, which was performed in the same way as at baseline, see Figure 6. Some subjects were unable to participate in the last musculoskeletal ultrasound measurement for various reasons. The measurement results are shown in Table 5 . The patellar tendon thickness in the combined and HSR groups exhibited a slight increase from baseline, yet this was not statistically significant. In contrast, the TUS group demonstrated a more pronounced and significant increase in patellar tendon thickness from baseline (p < 0.05). Comparative analysis of the three groups revealed no significant differences in tendon thickness before and after the intervention. 7. Discussion Heavy slow resistance training (HSR) and therapeutic ultrasound are commonly used in musculoskeletal disorder rehabilitation. While both are often used for patellar tendinopathy, using either alone may not be effective in some cases( 47 , 48 ). Research shows that HSR training can increase collagen production in the tendon, leading to pain relief. However, this effect may be limited in individuals with severe squatting difficulties or intense pain during squatting ( 49 ). On the other hand, high-dose therapeutic ultrasound (TUS) can raise the tendon's internal temperature, promoting healing( 14 ). This study aimed to evaluate the effectiveness of combining HSR training with high-dose TUS for treating patellar tendinopathy, focusing on pain reduction, strength, athletic performance, and balance. The VISA-P score questionnaire results showed that participants in the HSR training group had an average improvement of 17 points compared to their baseline scores. In contrast, those in the TUS treatment group saw an average increase of 6 points, while participants in the combination group had an average improvement of 21 points. The study suggests that combining high-dose TUS with HSR training had a significant short-term positive effect on PT. For chronic PT cases, HSR training was more effective in reducing pain than high-dose TUS alone, which had limited pain-relief benefits. Although the high-dose TUS group showed statistically significant improvements in VISA-P scores post-intervention, these improvements did not reach the minimum clinically important difference (MCID) of 13 points for PT symptom improvement( 28 ). In the 16th week, a follow-up was conducted with participants to collect their Visa-P score questionnaires. The VISA-P scores were 77.3 ± 10.4 (ranging from 52 to 94) for subjects in the HSR training group, 74.0 ± 7.5 (ranging from 63 to 84) for subjects in the TUS treatment group, and 82.8 ± 6.2 (ranging from 74 to 92) for subjects in the combined group. The results showed that the combined group and HSR group demonstrated more sustained improvements after the intervention ended, while the TUS group experienced a significant decrease in treatment effectiveness post-intervention. This suggests that in clinical settings using ultrasound therapy for patellar tendon disease, attention should be given to the continuity of treatment. Further research is needed to determine the duration of treatment necessary for the tendon to undergo adaptive changes, as indicated in the supplementary data. Our study utilized a TUS dosage of 4920 joules; however, due to limited research on the optimal TUS dosage for tendinopathy treatment, it is possible that the lower dosage parameters used may not have been adequate to generate significant clinical effects. Our hypothesis was that the combined group would exhibit more significant improvements in standing jump distance post-training, given that patellar tendinopathy (PT) is commonly associated with pain during jumping and landing( 47 ). However, the results showed considerable variability, with no significant differences noted between pre- and post-intervention assessments (P > 0.05). This variability could be due to the focus of high-speed resistance (HSR) training on eccentric and concentric contractions, which may not fully align with the explosive nature of vertical jumps. Moreover, all three experimental groups demonstrated significant improvements in balance abilities, particularly the Combined group, suggesting the potential benefits of HSR training in enhancing dynamic stability and balance by improving muscle control over postural changes. In contrast, therapeutic ultrasound therapy, a common physical therapy modality, primarily relies on thermal and mechanical effects to aid tissue repair and regeneration. While previous studies have shown some therapeutic effects of ultrasound therapy on certain musculoskeletal conditions, its impact on balance abilities remains inadequately studied and confirmed. Some participants initially reported pain hindering their performance in the Y-Balance Test (YBT) during baseline measurements, but this hindrance notably decreased after 8 weeks of intervention. Hence, the improvement in balance abilities among the therapeutic ultrasound (TUS) group participants may be linked to pain relief. However, further research and discussion are necessary to explore the influence of pain on test outcomes. Further research and discussion are needed to explore the impact of pain on test results. Future studies could delve into the potential influence of pain on balance abilities and the effectiveness of different intervention methods in pain regulation. HSR training significantly contributed to the improvement of quadriceps flexibility, whereas the ultrasound group showed limited improvements. This difference is likely attributed to the specific exercises chosen. These findings suggest that resistance training offers notable benefits for enhancing muscle flexibility, as it can enhance flexibility by modifying the length-tension relationship of muscles and the adaptability of the nervous system( 50 ). The closed-chain lower limb exercises we utilized not only directly impact the muscles but also influence the entire lower limb movement pattern, potentially modifying the flexibility of the quadriceps. However, the question of whether the alteration in lower limb movement patterns primarily contributes to the enhancement of quadriceps femoris flexibility, or if the improvement in quadriceps femoris flexibility predominantly induces changes in lower limb movement patterns, remains a topic that necessitates further investigation. Subsequent research endeavors could delve into thoroughly examining the causal relationship between the improvement in quadriceps femoris flexibility and alterations in lower limb movement patterns. Through the implementation of more sophisticated research methodologies and biomechanical analyses, a more comprehensive understanding of the reciprocal influence mechanisms between muscle flexibility and movement patterns can be attained. The study found a significant increase in the maximum isometric strength of participants, offering valuable insights into the performance of both the combined and training groups in terms of strength improvement. This information is particularly beneficial for high-level athletes during their competitive season. The combined group showed a 42% increase compared to pre-intervention levels, while the training group saw a 30% increase, suggesting multiple factors may have contributed to this growth. The rise in strength can be partially attributed to neuromuscular adaptation effects. Through strength training, muscle tissue undergoes various adaptive changes, such as increased muscle fibers and enhancements in the nervous system, which enable muscles to generate force more efficiently. These findings align with previous research indicating that prolonged training can enhance muscle strength( 8 , 48 , 51 ). For in-season athletes, the use of a combined intervention program can both reduce pain and maintain muscle strength to ensure good athletic performance. In the study of electromyographic signals, an interesting phenomenon was observed in in-season athletes undergoing a combined intervention program. After 8 weeks of biomechanical tests, it was noted that nearly all subjects experienced a decrease in electromyographic signals in the anterior muscles, specifically the vastus medialis obliquus (VMO) and vastus lateralis obliquus (VLO), during single-leg squats. Moreover, there was a varied reduction in the VMO/VLO ratio. The interpretation suggests that the reduction in pain led to an enhancement in the patellar tendon's mechanical transmission capacity. This improvement in mechanical transmission led to a notable decrease in the quadriceps' workload during the single-leg squat, as evidenced by a decline in EMG signals. Additionally, the decrease in the VMO/VLO ratio indicates a reduction in knee valgus and hip adduction angles during squatting post-intervention, possibly due to pain relief influencing lower limb movement strategies and joint kinematics to some extent. Further research is necessary to elucidate the impact of patellar tendon pain on lower limb movement strategies in athletes with patellar tendinopathy( 52 ). Additional research is needed to clarify the effects of patellar tendon pain on lower limb movement strategies among athletes with patellar tendinopathy. The results of patellar tendon color Doppler ultrasonography in the subjects demonstrated a notable reduction in blood flow within the tendon following an 8-week exercise intervention compared to pre-intervention. This finding is in line with the outcomes of Koenig et al.'s research( 8 , 53 ). Exercise intervention may facilitate the normalization of blood vessel distribution around the tendon, diminish the formation of abnormal vessels within the patellar tendon, and lower the concentration of specific neurotransmitters in the tendon blood vessels, ( 54 ) potentially contributing to the decrease in pain levels observed in the subjects. Regarding changes in patellar tendon thickness, participants in all three groups displayed varying degrees of increased thickness post the 8-week intervention period( 55 ). Nonetheless Kongsgaard et al.'s study( 8 ) noted a significant 45% decrease in tendon thickness among subjects in the HSR exercise group by week 12, approaching the original fiber morphology of healthy tendons( 16 ). It is possible that between the 8th and 12th weeks post-intervention, the tendons underwent adaptive changes, resulting in a reduction in thickness for tendons that initially thickened during the early intervention period. Agergaard et al.( 56 ) conducted musculoskeletal ultrasound measurements of patellar tendons in two high-speed resistance exercise intervention groups at baseline, 6 weeks, 12 weeks, and 52 weeks. They observed an initial increase in tendon thickness in both groups from baseline to 6 weeks, followed by a decrease in tendon thickness from 6 to 12 weeks, which aligns with our initial hypothesis. However, it is important to acknowledge that variations in the ultrasound measurement techniques utilized could also contribute to discrepancies in results. Future studies should consider employing standardized musculoskeletal ultrasound measurements. Tsai et al. ( 57 ) proposed that extracorporeal ultrasound may facilitate tendon healing, although the specific mechanisms underlying this process remain unclear. Our research demonstrated a significant increase in patellar tendon thickness among participants receiving extracorporeal high-energy dose ultrasound therapy after an 8-week intervention, compared to baseline measurements. As we did not perform ultrasound assessments at the 12-week mark, the potential impact of extended extracorporeal ultrasound intervention on tendon thickness remains unknown. In summary, we hypothesize that damaged tendons undergo a thickening process during recovery towards a healthy tendon structure, possibly due to the formation of new scar tissue. Further comprehensive investigations are warranted to elucidate the precise timeline of scar tissue development and resolution within the tendon. The majority of participants adhered to a supervised exercise program three times a week, a key strength of the experiment. The subjects' training and rest periods were closely monitored to ensure completion of the program. All participants underwent follow-up assessments after 16 weeks in a controlled environment at designated facilities to minimize external interference. The study included university student athletes from Wuhan Sports University, providing a reasonably representative research population. However, the study has several limitations that should be considered in future research. The intervention instructors were not blinded, potentially impacting outcomes. To address this, additional training was provided to ensure consistent execution of exercises and communication of experimental details with participants was minimized. Participants engaged in various sports disciplines, and although encouraged to limit unrelated physical activities during the 8-week intervention, some may have still engaged in other sports, potentially affecting results. Kinematic evaluation involved participants squatting on an inclined platform before and after the intervention. During baseline testing, a small number of participants experienced patellar tendon pain when attempting to lower their bodies to the specified angle. For safety reasons, we allowed these participants to rise after reaching the maximum angle they could tolerate. It is important to highlight that in the post-8-week test, all participants successfully squatted to the specified angle, potentially leading to an increased risk of Type I errors. Additionally, our follow-up with participants only extended to 16 weeks, limiting our ability to assess the long-term effectiveness of exercise intervention on patellar tendon diseases. Further research is needed to explore the efficacy of exercise intervention in addressing this aspect. Our research findings indicate that the combination of Heavy Slow Resistance training and high-dose ultrasound therapy leads to substantial improvements in pain and functionality for patients with patellar tendinopathy. This combined approach is particularly effective in reducing symptoms in chronic patients, making it a suitable protocol for individuals with severe symptoms or those seeking improved athletic performance. Abbreviations BF ： Biceps femoris ESWT ： Extracorporeal shockwave therapy EET ： Eccentric exercise training EMG ： Electromyography HSR ： Heavy slow resistance MTT ： Modified Thomas Test MVIC ： Maximum Voluntary Isometric Contraction MIMS ： Maximal isometric muscle strength RMS ： Root mean square TLT ： Tendon-loading training TUS ： Therapeutic ultrasound VAS ： Visual Analogue Scale VISA-P ： Victorian Institute of Sport Assessment-Patella VLO ： Vastus lateralis obliquus VMO ： Vastus medialis obliquus PT ： Patellar tendinopathy YBT ： Y-Balance Test Declarations Ethics declaration The experimental protocol was established, according to the ethical guidelines of the Helsinki Declaration and was approved by the Human Ethics Committee of Wuhan Sports University. Written informed consent was obtained from individual or guardian participants Consent for publication Not applicable. Informed consent form Prior to the start of the experiment, informed consent forms should be provided, requiring participants to know the specific protocol and risks of the experiment, and to sign informed consent forms after understanding the protocol. Funding This study is not funded. Competing interests The authors declare they have no competing interests. Availability of data and materials All data generated or analyzed during this study are included in this published article (and Additional file 1 Acknowledgements We extend our gratitude to the Wuhan Sports University for providing the intervention site for this experiment and to all the subjects and staff who participated in this experiment. References Scott A, Squier K, Alfredson H, Bahr R, Cook JL, Coombes B, et al. ICON 2019: International Scientific Tendinopathy Symposium Consensus: Clinical Terminology. Br J Sports Med. 2020;54(5):260-2. Xu Y, Murrell GA. The basic science of tendinopathy. 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Effect of therapeutic ultrasound on tendons. Am J Phys Med Rehabil. 2011;90(12):1068-73. Tables Table 1 Therapeutic ultrasound (TUS) dosimetric parameters Parameters Adjusts Frequency 1MHZ Mode Continuous Time 10min Energy 4920J / per application Effective radiation area 5.5cm 2 Table 2 the features of the subjects. Combined group (N=17) HSR group (N=17) TUS group (N=17) P-Value Age (yrs) 21.41±1.46(19-24) 22.12±1.616 (19-25) 21±1.458(19-24) ＞0.05 Height (m) 1.785±0.080 (1.65-1.92) 1.812±0.055 (1.70-1.90) 1.799±0.081 (1.67-1.92) ＞0.05 Weight(kg) 71.65±11.20 (55-95) 76.35±7.911 (63-90) 75.66±14.01 (55-102) ＞0.05 BMI (kg/m 2 ) 22.38±2.190 (19.03-26.81) 23.22±1.574 (19.44-25.76) 23.23±2.909 (17.36-28.37) ＞0.05 Symptom duration (months) 7.235±5.203(3-24) 16.76±18.72(3-70) 9.176±7.00(3-24) ＞0.05 Gender (male/female) 14/3 17/0 15/2 ＞0.05 Primary sport 4 Soccer 6 Running 2 Basketball 3 Table Tennis 1 Unknown 1 Fitness 3 Gymnastics 4 Tennis 4 Badminton 5 Basketball 2 Unknown 3 Fitness 3 Golf 4 Basketball 1 Badminton 3 Fitness 2 Running 1 Unknown Table 3 Changes in selected indicators before and after intervention Combined group (N=17) HSR group (N=17) TUS group (N=17) P-Value VAS-△0w 6.794±1.552 (3-9) 6.971±1.494 (5-10) 6.647±1.183 (5-9) 0.8021 VAS-△8w 2.059±0.9334 (1-4)** ＆△△ 2.882±1.139 (1-5)** 3.294±0.8671 (2-5)** 0.0023 YBT-△0w 0.8778±0.07586 (0.7343-0.9883) 0.9290±0.07846 (0.7828-1.025) 0.9160±0.07203 (0.7913-1.019) 0.1319 YBT-△8w 0.9669±0.0772 (0.8238-1.060)** 0.9917±0.06974 (0.8655-1.097)** 0.9595±0.07888 (0.8046-1.091)** 0.4337 MTT-△0w 51.55±1.303 (50.0-55.0) 51.72±2.152 (49.0-55.4) 52.35±1.868 (49.8-56.0) 0.4046 MTT-△8w 54.84±1.703 (52.2-58.2)** △ 54.39±2.218 (51.1-58.3)** 52.77±1.966 (50.7-57.1) 0.0092 MIMS-△0w 216.7±56.03 (118.0-308.0) 254.4±36.91 (201.5-353.0) 235.6±46.11 (161.0-322.5) 0.0747 MIMS-△8w 295.4±73.63 (157.0-432.5)** 326.7±78.78 (194.5-494.0)** 282.4±90.27 (169.5-476.5)* 0.2724 Horizontal Jump-△0w 225.3±25.65 （170-275） 231.1±22.91 （189-266） 229.5±32.09 （170-286） 0.8131 Horizontal Jump-△8w 232.1±18.00 （197-255） 231.3±21.53 （194-262） 231.1±27.09 （180-282） 0.9916 Values are means ± SD Values in brackets are range **Siginificantly different from 0 week (p＜0.01) *Significantly different from 0 week(p＜0.05) △ Significantly different from TUS group(p＜0.05) △△ Significantly different from TUS group(p＜0.01) ＆ Significantly different from HSR group(p＜0.05) Table 4 Changes in VMO/VLO after 8 weeks of intervention Combined group (N=15) HSR group (N=14) TUS group (N=15) F P-Value VMO/VLO-△0w 1.3±0.55 （0.84-2.7） 1.3±0.85 （0.53-3.7） 1.2±0.60 （0.68-2.9） 0.09 0.9064 VMO/VLO-△8w 0.93±0.19 （0.64-1.3） 0.94±0.23 （0.58±1.5） 1.0±0.21 （0.66-1.3） 0.5 0.5907 Values are means ± SD There was no significant difference between the groups before and after the intervention. Table 5 Changes in patellar tendon thickness after 8 weeks of intervention Values are means ± SD There was no significant difference between the groups before and after the intervention. Additional Declarations No competing interests reported. Supplementary Files suppmentarydata.docx Cite Share Download PDF Status: Published Journal Publication published 10 Oct, 2024 Read the published version in BMC Sports Science, Medicine and Rehabilitation → Version 1 posted Editorial decision: Revision requested 20 Jun, 2024 Editor assigned by journal 20 Jun, 2024 Submission checks completed at journal 19 Jun, 2024 First submitted to journal 18 Jun, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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03:15:48","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4602813/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4602813/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s13102-024-01004-2","type":"published","date":"2024-10-10T15:57:04+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":60601458,"identity":"ce071a4b-b7c7-424c-9870-60e986f8510e","added_by":"auto","created_at":"2024-07-18 16:05:32","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":51575,"visible":true,"origin":"","legend":"\u003cp\u003eFlow chart (CONSORT)\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4602813/v1/bbb051365fa39b79eea2080a.jpg"},{"id":60601459,"identity":"e9c8c42d-0888-433d-91ee-1817cdab6425","added_by":"auto","created_at":"2024-07-18 16:05:33","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":38444,"visible":true,"origin":"","legend":"\u003cp\u003etraining program of HSR group\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4602813/v1/85356801fe44bc4804f0dd25.jpg"},{"id":60602336,"identity":"c20f75ce-3d2e-43ba-ba40-e29dc2e699b4","added_by":"auto","created_at":"2024-07-18 16:13:33","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":21213,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of YBT test action\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4602813/v1/2241f39182dfb9be68f8cc32.jpg"},{"id":60601457,"identity":"c1195be3-1006-40f3-879c-d30634f60df7","added_by":"auto","created_at":"2024-07-18 16:05:32","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":20525,"visible":true,"origin":"","legend":"\u003cp\u003eThe MTT test schematic\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4602813/v1/5bb98b1db0f946f8c946b42e.jpg"},{"id":60601461,"identity":"c8172d9a-ee9b-4674-bbbc-083925962b0c","added_by":"auto","created_at":"2024-07-18 16:05:33","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":27612,"visible":true,"origin":"","legend":"\u003cp\u003eRatio of VMOVLO in the three groups in the EMGS analysis before and after the intervention\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4602813/v1/84bb49706d8863bd6639052a.jpg"},{"id":60601463,"identity":"aea756cd-72c6-443c-a3c1-4644c36cfd1e","added_by":"auto","created_at":"2024-07-18 16:05:34","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":32278,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in patellar tendon thickness before and after intervention in three groups with musculoskeletal ultrasound imaging\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4602813/v1/bd7d37af7b69b0f29a3a03ab.jpg"},{"id":66597056,"identity":"4645a017-ffaa-48bc-8f42-e31710c6e334","added_by":"auto","created_at":"2024-10-14 16:06:18","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":924312,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4602813/v1/30c54abe-a05a-4062-8fd9-653bc7653a58.pdf"},{"id":60601462,"identity":"7c5bedc9-2230-4274-89d9-618d76a2f6cb","added_by":"auto","created_at":"2024-07-18 16:05:33","extension":"docx","order_by":8,"title":"","display":"","copyAsset":false,"role":"supplement","size":166311,"visible":true,"origin":"","legend":"","description":"","filename":"suppmentarydata.docx","url":"https://assets-eu.researchsquare.com/files/rs-4602813/v1/144c288d808825a32f45343b.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comprehensive Assessment of Heavy Slow Resistance Training and High-Dose Therapeutic Ultrasound in Managing Patellar Tendinopathy","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003ePatellar tendinopathy (PT) is a common chronic sports injury characterized by significant pain in the proximal patellar tendon(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Patients with this condition often experience tenderness in the patellar tendon area, as well as a decrease in strength and mobility in the surrounding region(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). A study published in the 2020 British Journal of Sports Medicine highlighted that individuals with PT frequently face persistent pain and functional limitations, particularly during weight-bearing activities or those involving significant impact forces(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). T Symptoms typically worsen post-activity, and PT is frequently observed in sports that require high levels of speed and strength, such as volleyball and basketball, which heavily engage the leg extensor muscles(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Research has shown that approximately 52.3% of basketball players suffer from PT, leading to a noticeable decline in their athletic performance(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). PT tends to persist as a long-term issue, posing challenges for effective management without intervention(\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). Current treatment approaches for PT encompass a combination of passive and active modalities(\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Passive treatments include options like medication, injections, extracorporeal shockwave therapy (ESWT), ultrasound, and low-intensity lasers. Active treatments involve strategies such as tendon loading training (TLT)(\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e),HSR training(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e) and eccentric exercise training(ECC) (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e) etc.\u003c/p\u003e \u003cp\u003eTherapeutic ultrasound (TUS) is a frequently employed therapeutic modality in the field of physical therapy(\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Many studies have explored the effectiveness of therapeutic ultrasound in treating PT, with favorable results reported in certain cases. (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). TUS has been shown to stimulate the self-repair mechanism of the patellar tendon, increase its temperature, raise the pain threshold, and promote collagen elongation. Additionally, high-dose TUS can influence the tissue structure of the patellar tendon, facilitating improved energy absorption and dispersion, thereby enhancing knee joint function in patients with PT, research has indicated that both high-dose and low-dose TUS can ameliorate PT, with high-dose TUS demonstrating greater effectiveness(\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eHSR training, including exercises like barbell squats and deadlifts, has been demonstrated to induce localized hypertrophy and enhance the mechanical chattels of the patellar tendon region (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). HSR training focuses on stabilizing the centrifugal and centripetal phases of the loading movement, which enhances the subject's neurological adaptations as well as greater strength variability, and is effective in improving tendon swelling and vascularization(\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). As a therapeutic strategy for individuals with patellar tendon pain and to improve knee extensor strength, HSR training can be utilized(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). The objective of this study was to assess the effects of HSR training on individuals with PT. We conducted HSR training and/or therapeutic ultrasound interventions on young athletes with PT to explore the therapeutic outcomes of these various physiotherapy approaches. Our goal was to establish a theoretical foundation for more effective PT treatments.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cp\u003eDESIGN: This study was designed as a single-blind, randomized controlled trial. \u0026nbsp;Subjects, imaging physicians, and experimental data collectors were blinded. The participants were randomly assigned to groups using the envelope method. The objective was to assess the effectiveness of HSR therapy in combination with high-dose therapeutic ultrasound and combined therapy for patellar tendinopathy by comparing pre- and post-intervention data. We implemented rigorous experimental protocols, limiting the study to the Sports Intervention Center of Wuhan Sports University, employing a consistent experimental site, and enlisting a highly trained therapist. As a result, the confidence level in the experiment\u0026apos;s validity was significantly elevated.\u003c/p\u003e\n\u003ch2\u003e2.1 Subjects\u003c/h2\u003e\n\u003cp\u003eFrom October 2022 to May 2023, 53 college students with chronic patellar tendinopathy in the age range of 18 to 24 years old, including 46 males and 5 females, were recruited at Wuhan Sports University, and the subjects were centrally intervened for a period of 8 weeks (diagnosed by an orthopedic deputy chief physician with 15 years of clinical experience. The subjects were identified as having chronic patellar tendinopathy only if the duration of pain was greater than three months.(20) The diagnosis was supported by ultrasonography. Diagnosis was supplemented with ultrasound imaging to leave out patellofemoral pain syndrome (PFPS) based on a patellofemoral pain statement(21). \u003cstrong\u003eTable 2\u003c/strong\u003e shows the rudimentary features of the subjects.\u003c/p\u003e\n\u003cp\u003eThe criteria for subject inclusion in the experiment were 1. Subjects with a VISA-P questionnaire score of \u0026lt;80 out of 100(22, 23),2. history of patellar tendon pain related to training or competition, 3. structural changes in the patellar tendon on gray-scale ultrasound and/or increased tendon vascular distribution on energy Doppler(24),4. significant tenderness on palpation near the end of the patellar tendon and pain limited to the inferior level of the patella(25) 5. pain aggravated by squatting or jumping. Ultrasonography was performed by a 15-year-experienced sonographer, and was positive for the presence of patellar tendon structural changes and/or hypoechoic changes and/or thickening of the patellar tendon (anterior-posterior diameter \u0026gt;6 mm) and/or increased intratendinous Doppler flow(26).All subjects signed a written informed consent before the start of the experiment.\u003c/p\u003e\n\u003cp\u003eSubjects will be excluded on the basis of 1. duration of pain less than three months, 2. acute knee or patellar tendon injury with a history of knee surgery in the past year, 3. presence of inflammatory arthropathy with use of potentially affecting patellar tendon medications (e.g., quinolones) in the past year, 4. use of corticosteroids for topical injections in the past month, 5. history of past patellar tendon rupture, 6. failure to perform a training program or participate in other treatment programs 7. Exercise program, or participation in another treatment program, physical examination or ultrasound/MRI findings of other coexisting knee pathology, 8. Inability to undergo high-energy does ultrasound therapy or indications that ultrasound is contraindicated such as (active tuberculosis, bleeding tendency, severe cardiac disease, malignant tumors, venous thrombosis, and pregnant women). Each subject was informed of the procedure before the start of the experiment and gave a paper informed consent form. All data from the subjects were authorized. \u003cstrong\u003eFigure 1\u0026nbsp;\u003c/strong\u003eshows the flow chart with the summary experimental procedures and the situation of participants, \u0026nbsp;according to the Consolidated Standards of Reporting Trials (CONSORT)(27).\u003c/p\u003e\n\u003ch2\u003e2.2 Blinding and randomization\u003c/h2\u003e\n\u003cp\u003eBefore initiating the study, all participants were familiarized with the research procedures following a baseline assessment. After including subjects who met the required criteria, baseline data were collected to minimize potential data interference. It is important to note that non-research team members collected the baseline data. It is important to note that non-research team members collected the baseline data. Allocation concealment was ensured by an experimenter (L.Z.Y.), who did not participate in follow-up data collection. Subsequently, L.Z.Y recorded the groupings on paper and sealed them in an opaque envelope. The envelope was handed to the subject; upon completing baseline data collection, the subject returned the envelope to the interventionist, who then administered the corresponding group intervention. Subjects remained unaware of their group assignments. The study required that subjects not discuss any exercise regimens or therapeutic measures during the study period. The intervention was supervised by two therapists (HJ, NX), who were not involved in the group assignment. The imaging physician remained blinded during the outcome data collection.\u003c/p\u003e"},{"header":"3.\tInterventions","content":"\u003ch2\u003e3.1. HSR Training\u003c/h2\u003e\n\u003cp\u003eHeavy slow resistance training methods, as demonstrated by Kongsgaard (8) , , involved intervention protocols with symmetrical loading on both legs. Despite this, subjects may have altered their center of gravity as a result of pain in the affected leg. Furthermore, a significant number of subjects reported experiencing symptoms primarily in one leg, indicating potential benefits of one-legged training. In order to enhance the training impact, one of the Hacker squats was substituted with the Bulgarian Deep Squat. (Figure 2). The training protocol follows NSCA-CSCS standards, emphasizing low bar position barbell squats. Proper form is crucial, with instructions to maintain a straight back, elevate elbow joints, bend hips and knees, and squat slowly until reaching a 90\u0026deg;knee angle. Consistent and stable movement without compensation is essential throughout the training. For the Bulgarian Deep Squat, the subject positions themselves in front of a bench or similar surface, about two feet away, with their back facing the surface. One leg is extended back with toes resting on the bench, ensuring the front foot is positioned far enough to maintain proper alignment during the squat. The subject then lowers until the knee reaches a 90-degree angle, maintaining perpendicular alignment with the surface. Three training sessions were conducted weekly, with bilateral movements on the body and a 2-minute rest between sets. The repetitions/load intensity varied from 12RM in the first two weeks, 10RM in the third and fourth weeks, 8RM in the fifth and sixth weeks, and 6RM in the seventh and eighth weeks. Subjects followed a metronome, spending 3 seconds on both the centrifugal and centripetal phases of the movement (totaling 6 seconds for each movement). To enhance the mechanical properties of the tendon and facilitate adaptations, Morrison et al. (19)recommend a loading protocol with an intensity of \u0026gt;70% 1RM (the weight that can be performed only once for a standard movement) for the lowest resistance training in HSR training. This requires ensuring that subjects perform no more than 12 repetitions. Participants with partial pain (VAS \u0026lt;3) were permitted, as long as pain did not increase in subsequent sessions. A therapist supervised each session to ensure accuracy, completion of training maneuvers, and the safety of the subjects. Each session included a pre-training warm-up and post-training stretching.\u003c/p\u003e\n\u003ch2\u003e3.2. High-dose TUS therapy\u003c/h2\u003e\n\u003cp\u003eHigh-dose TUS therapy was administered to both the combined and TUS groups as part of the intervention. The combined group received this therapy following the completion of their training. High-dose TUS therapy (ULTRASOUND UNIT US-700, Japan) targeted only the patellar tendon region. Full contact was maintained between the subject\u0026rsquo;s patellar tendon and the high-energy TUS conductor, with gel used as the interface. Throughout the procedure, subjects were positioned supine with a cushion under the knee for immobilization, and the knee was slightly flexed at approximately 20 degrees (14). If subjects exhibited bilateral symptoms, the knee with the more severe symptoms received high-dose TUS treatment. Details on the dosage settings and duration of high-dose TUS are provided in \u003cstrong\u003eTable1\u003c/strong\u003e.\u003c/p\u003e\n\u003ch2\u003e3.3. Combination therapy\u003c/h2\u003e\n\u003cp\u003eThe combined group followed the same 8-week training regimen as the training group. Each subject completed three weekly training sessions, each consisting of three maneuvers, as depicted in Fig. 1. Participants performed four sets of each maneuver, taking a 2-minute break between sets. Immediately following the training sessions, subjects received high-dose TUS therapy, using identical treatment parameters, duration, and materials as those used in the TUS group.\u003c/p\u003e"},{"header":"4.\tOutcome measure","content":"\u003cp\u003eThe primary outcome was the VISA-P questionnaire. We used the VISA-P questionnaire to enumerate the level of symptoms and participation in functional activities in PT patients(23) . Higher questionnaire scores were associated with better functioning, with a minimal clinical difference of 13 points(28) . The patients all completed the completed questionnaires autonomously without any assistance after a brief explanation of the questionnaire by the main researcher assistant (HJ). The questionnaire was administered at baseline, 8 weeks and16 weeks.\u003c/p\u003e\n\u003cp\u003eSecondary outcomes were as follows. When subjects exhibited symptoms on both sides, the more severely affected side was selected for inclusion in the test report. To ensure data consistency, the same researcher (L.Y.C.) conducted all data collection. Additionally, at each subsequent test and follow-up, subjects were reminded of their initial selection. Should a subject sustain a physical injury or request to terminate participation at any stage of data collection or training, the experiment was immediately halted.\u003c/p\u003e\n\u003ch2\u003eVAS\u003c/h2\u003e\n\u003cp\u003eWe used a 10-cm Visual analogue scales to evaluate the grade of patellar tendon pain in the subjects, with a score of 0 indicating the absence of any pain and a score of 10 indicating the most severe pain, with higher scores representing more severe pain(29). After a brief questionnaire science was administered to the subjects, the patients were asked to squat on a 25\u0026deg; inclined platform(30), and the patients assessed the degree of patellar tendon pain during squatting using the VAS scale by themselves, during which the evaluator did not provide any kind of guidance to them. The tests were performed before and 8 weeks after the intervention, respectively.\u003c/p\u003e\n\u003ch2\u003eLower Quarter Y Balance Test\u003c/h2\u003e\n\u003cp\u003eThe Lower Quarter Y Balance Test (YBT-LQ) is an instrument used to evaluate dynamic postural control, which is a variant of the Star Rapids Test (SEBT) that reflects a subject\u0026apos;s ability to balance, and whose reliability and validity have been tested(31) . We hypothesized that HSR training would improve subjects\u0026apos; balance ability. The test methodology used was similar to that of Plisky et al.(31) used, but participants were asked to put their hands on the pelvis to exclude the influence of the upper extremities on balance. Participants extended their other leg to push the test board as far as possible in three directions: anterior-lateral, posterior-medial, and posterior-lateral, in order to move the test board to the farthest possible distance \u003cstrong\u003e(Figure 3)\u003c/strong\u003e, and then returned to the beginning position after each test, with the foot unable to get in touch with the ground or rely on the test block for support during the test, and the distance of the push was recorded. Each participant performed four experiments with each leg in each direction of extension before the official test, and the participant\u0026apos;s performance reached stability(32) The experiment was formally started after a 5-minute rest, and the maximum of the three test results was taken and analyzed. Participants were positioned supine, and their lower limb length\u0026mdash;measured from the anterior superior iliac spine to the center of the ipsilateral medial ankle(33) , measured in centimeters. Considering the significant differences in leg length and height of individual subjects, the nudge distance was normalized to the lower limb length of the participant, and the maximum reach distance (%MAXD) was calculated by using the formula (6 farthest distance/length of both lower limbs (a, b) \u0026times; 3) \u0026times; 100%MAXD)(34, 35). YBT tests will be measured at baseline and at the end of the intervention.\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/132203_cef980177e9a226b/132203_custom_files/img1720543108.png\" width=\"292\" height=\"64\"\u003e\u003c/p\u003e\n\u003ch2\u003eModified Thomas Test (MTT)\u003c/h2\u003e\n\u003cp\u003eInsufficient flexibility and strength in the quadriceps muscle have been identified as potential pathogenic factors in patellar tendinopathy(36). Reduced flexibility of the quadriceps muscle results in a larger knee flexion angle and a slighter hip flexion angle during landing(37), leading to increased loading of the tendon, subsequently inducing degenerative alterations in the patellar tendon. To evaluate quadriceps flexibility, we utilized the modified Thomas test. During this test, participants sat at the end of the treatment bed, bowled backward onto the bed, and curled both knees in front of the chest. It was ensured that the lumbar spine remained flat against the bed and the pelvis maintained a posteriorly rotated position. The subject held the contralateral knee with both arms so that the leg it\u0026rsquo;s in maximum flexion while relaxing the affected limb and lowering it toward the floor, and the subject\u0026apos;s affected knee flexion angle was measured by means of a protractor.(38) \u003cstrong\u003e(Figure 4)\u003c/strong\u003e We will compare the change in this angle between baseline and after 8 weeks of training to determine if HSR training enhances quadriceps flexibility in our subjects. Tests were performed once with baseline and once after the 8-week intervention.\u003c/p\u003e\n\u003ch2\u003eMaximum isometric strength of lower extremity extensors\u003c/h2\u003e\n\u003cp\u003eSubjects underwent testing for isometric maximal strength of the lower extremities using the Leg-Check 626 lower extremity strength stirrup machine (Dr. WOLFF Sports \u0026amp; Prevention GmbH - Bachumer Weg 70 -D 59757 Arnsberg, Germany). Before initiating the test, participants were instructed to adjust the backrest angle. And then to place the legs on the base plate of the device with the knees at 90\u0026deg; (see figure). At the beginning of the test, subjects were told to keep their backs against the backrest, and then to gradually exert their legs to exhaustion in order to avoid transient explosive force interfering with the experiment. Tests were performed once with baseline and once after the 8-week intervention.\u003c/p\u003e\n\u003ch2\u003eHorizontal Jump\u003c/h2\u003e\n\u003cp\u003eThe subjects were tested using the standing long jump tester (Tsinghua Tong fang Electronics, CHINA), the therapist gave a verbal description and demonstration of the test, the subjects were asked to wear non-slip sports shoes. Before the test, participants underwent a 5-minute warm-up session. Following this, they were familiarized with the jumping action before commencing the test procedure. Participants were informed to position behind the jumping line with their feet naturally separated, and with their feet in the original position. Jump forward at the same time, note that there should be no padding or jumping action, each person tested twice, and record the maximum value of the two valid test values. Tests were performed once with baseline and once after the 8-week intervention.\u003c/p\u003e\n\u003ch2\u003eThe EMG of the muscles of the lower extremities\u003c/h2\u003e\n\u003cp\u003ePT has been demonstrated to impact lower extremity kinetics(39) , potentially leading athletes to experience issues during landing(40), affecting the hip joint(39, 40) and ankle joints(40, 41), thereby inducing kinematic alterations. Risk factors for PT include quadriceps strength, flexibility of the posterior thigh muscles, among others(42).\u0026nbsp;Although fewer studies have investigated the effect of training on muscle activation levels in PT patients, we hypothesized that 8 weeks of high-load strength resistance (HSR) training would modulate the activation levels of the vastus medialis oblique (VMO), vastus lateralis oblique (VLO), and biceps femoris (BF) during eccentric squatting on an inclined platform in PT patients. A wireless surface electrode (Noraxon, USA) was used to record the muscle activations of the VMO,VLO,BF at a 1500 Hz sampling rate(43), to analyze the change in muscle activation during single-leg squats on a 25\u0026deg; inclined platform in subjects before and after the intervention. Prior to the start of the movement, all subjects were asked to perform a warm-up preparation activity on a stationary power bike for approximately 10 minutes. All subsequent movement exercises were demonstrated by the therapist (X.L.F) and subjects were ensured to be proficient in the test exercise maneuvers, which started with the determination of three Maximum Voluntary Isometric Contraction (MVIC) of the VMO, VLO, and BF muscles, and required that the duration of each MVIC be maintained above 5s. The duration of each MVIC was required to be kept above 5 s. A 1-minute rest was present between each exercise to facilitate muscle recovery, and the patients were verbally encouraged to strive for the best performance during the test. The subject was instructed to stand on the platform with the affected side (if symptoms were present on both sides, the side with the most severe symptoms was chosen), and then to perform a slow squatting motion until the knee joint reached a 90-degree angle, and after a short stay of 1s, the subject was asked to slowly get up, and the movement was kept at a constant speed throughout. The movement test was performed three times, with a 1-minute rest period between test movements. The raw surface EMG signals were full-wave rectified and then band-pass filtered at a cutoff frequency of 20-400 HZ. In each muscle MVC measured for each athlete, 1s data segments above and below the maximum value of EMG were averaged and thus normalized, and the results were expressed in terms of integral EMG and root mean square (RMS) amplitude.(44). RMS measures the average level of muscle discharge in a muscle over a specific period of time. Tests were performed once with baseline and once after the 8-week intervention.\u003c/p\u003e\n\u003ch2\u003eMusculoskeletal ultrasound image\u003c/h2\u003e\n\u003cp\u003eUltrasound procedure: Ultrasound imaging was conducted using a GE LOGIQ E11 ultrasound machine with an acquisition frequency of 9.0 MHZ. The procedure followed the guidelines of the European Society of Musculoskeletal Radiology. Subjects were positioned supine on an examination table with a pillow positioned under the popliteal fossa, maintaining knee flexion at approximately 30\u0026deg;(45).The sensor probe was placed longitudinally over the popliteal fossa. The transducer probe was placed longitudinally in the middle of the patellar tendon, and the probe was kept gently in contact with the skin the whole time without applying any additional pressure on the PT to prevent pressure from affecting the measurement, and the PT thickness was measured 1 cm from the patellar aponeurosis by using the scanner\u0026apos;s built-in software(46).Blood flow within the PT was also observed using color Doppler imaging.\u003c/p\u003e"},{"header":"5. Statistical analysis","content":"\u003cp\u003eThe data are presented as means\u0026thinsp;\u0026plusmn;\u0026thinsp;SD and range. Statistical analyses were performed using GraphPad Prism Version 9.0.0 and GPower version 3.1.9.4. General data were analyzed using the Kruskal-Wallis ANOVA test. Measurement data were tested for chi-square and confirmed to follow a normal distribution. Paired samples t-tests were conducted within the pre- and post-intervention groups. One-way repeated measures ANOVA by ranks was used to assess differences in values and relative change between groups. In cases of significant differences, a post hoc test was employed to determine significance between groups. All tests were conducted as two-tailed with an alpha level of 0.05.\u003c/p\u003e \u003cp\u003eThe sample size for this experiment was calculated using GPower3.1 software due to the repeated ANOVA design. An F test was used for sample size calculation with the following parameters: Effect size f\u0026thinsp;=\u0026thinsp;0.25, α err prob\u0026thinsp;=\u0026thinsp;0.05, Power (1-B err prob)\u0026thinsp;=\u0026thinsp;0.8, Number of groups\u0026thinsp;=\u0026thinsp;3, Number of measurements\u0026thinsp;=\u0026thinsp;6, Corr among rep measures\u0026thinsp;=\u0026thinsp;0. The software determined that a minimum sample size of 45 was required for the experiment, with 15 participants in each group. Recruitment has successfully met the minimum sample size requirement for the experiment.\u003c/p\u003e"},{"header":"6. Results","content":"\u003cp\u003e\u003cstrong\u003ePrimary outcome measure\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eVISA-P\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA repeated measures ANOVA showed that there was no significant difference in the visa-p scores of the three groups before the intervention (F=2.943, p=0.06), and after the 8-week intervention, there was a significant difference in the between-group comparisons (F=4.974, p=0. 01), and then post hoc multiple comparisons were performed, and the data analyses showed that the scores in the combined group differed significantly from the scores in the TUS group (p=0.008). significant difference (p=0.008). The VISA-P scores included an assessment of the subject\u0026apos;s pain symptoms as well as motor function, so based on the results it was learned that the combined group showed greater improvement for PT subjects than the TUS.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSecondary outcome measure\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;VAS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA repeated measures ANOVA was conducted on the collected VAS scores. The results of the pre-intervention between-group comparison of the VAS scores of the three groups indicated that there was no significant difference (F=0.2215, p=0.82). However, a post-hoc multiple comparisons analysis following the 8-week intervention revealed a significant difference (F=6.97). A post-hoc multiple comparisons test revealed a significant difference between the combined group and the HSR training group (p = 0.048), as well as between the combined group and the TUS treatment group (p = 0.001). This indicates that the combined group demonstrated greater efficacy in reducing the subjects\u0026apos; pain. Furthermore, a paired-samples within-group t-test was conducted on the pre- and post-intervention data for the three groups. The results demonstrated that all three treatments significantly reduced the subjects\u0026apos; VAS scores at the end of the intervention.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eYBT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA repeated measures ANOVA was conducted on the YBT data of the subjects before and after the intervention. The results demonstrated that there was no significant difference in the subjects\u0026apos; YBT test ability between the groups before the intervention (F=2.114, p=0.13). Additionally, there was no significant difference in the comparison of the groups after the 8-week intervention (F=0.8501, p=0.91). Furthermore, a within-group comparison of the three groups of subjects before and after the 8-week intervention using a paired-samples t-test for within-group comparisons revealed a significant difference in the YBT scores of all three groups of subjects before and after the intervention. This indicates that the subjects exhibited some degree of improvement in balance following the intervention, although this was not significant in the between-group comparisons.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMTT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA one-way repeated measures ANOVA was performed on the collected data from the MTT tests performed on the subjects before and after the 8-week intervention. The results of the between-group comparisons of the three groups of subjects before the intervention revealed no significant difference in MTT before the intervention (F=0.9221, p=0.404). Similarly, the between-group comparisons of the subjects\u0026apos; MTTs after the intervention yielded no significant differences (F=0.888, p=0.433). A second 8-week intervention was conducted, which revealed a significant difference (F= 5.182, p=0.009). A post hoc comparison indicated that the MTT test results of the subjects in the combined group were significantly different from those of the subjects in the TUS group. This indicates that the combination treatment was more effective than the TUS group in improving quadriceps flexibility. A paired-sample t-test was conducted to assess within-group differences in MTT scores before and after the intervention period for the three subject groups. The combined group demonstrated a significant improvement compared to the HSR group after 8 weeks, indicating that both the combined intervention and training regimen demonstrated the potential to enhance quadriceps muscle flexibility in subjects. However, no significant differences were observed between the pre- and post-intervention groups of the TUS group, indicating that the improvement in quadriceps muscle flexibility observed in subjects following TUS treatment was relatively limited.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaximum isometric strength of lower extremity extensors\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA one-way repeated measures ANOVA was employed to analyze the maximum isometric contraction moments of the lower extremity extensors of the subjects before and after the intervention between groups. The results indicated that there was no significant difference between the pre-intervention groups (F=1.336, p=0.27) and between the post-intervention groups (F=2.739, p=0.07). Subsequent within-group comparisons were made before and after the intervention, using paired samples t-tests. It was concluded that all three intervention modalities significantly improved the maximal isometric contraction strength of the lower extremity extensors, with p-values of \u0026lt;0.0001 in the combined group, 0.0018 in the HSR group, and 0.03 in the TUS group. The improvement was most significant in the combined group\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHorizontal Jump\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA comparison of the subjects\u0026apos; pre-intervention and post-intervention data was conducted within and between groups. The results indicated that there was no significant difference between the pre-intervention group comparisons (F=0.2077, p=0.81), and the post-intervention group comparisons were non-significant. A paired samples t-test was employed to conduct within-group comparisons of the subject data, and no significant differences were observed between the three groups before and after the intervention (p = 0.23, 0.95, and 0.77).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eThe EMGS of the muscles of the lower extremities\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe took the same test as at baseline and observed the changes in the EMG signals of the thigh muscles during the squatting process in the subjects. Seven subjects were unable to complete the posterior side due to conflicting testing schedules: two in the combined group, three in the HSR group, and two in the TUS group. To address variations in individual strength and the time required to complete the maneuver, we utilized the VMO to VLO ratio for pre- and post-comparison of the data, the results showed that compared to baseline, the signals of VMO and VLO were reduced in the three intervention groups , with the VMO/VLO of the combined group being 1.298\u0026plusmn;0.5491 before intervention and 0.9291\u0026plusmn;0.1925 after intervention, with significant differences between pre- and post-intervention (P\u0026lt;0.05) while there were no significant differences between pre- and post-intervention for the HSR and TUS groups, see \u003cstrong\u003eTable\u003c/strong\u003e \u003cstrong\u003e4\u0026nbsp;\u003c/strong\u003e.This addition to the three groups there was no significant difference between the groups before and after the intervention. See \u003cstrong\u003eFigure 5\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMusculoskeletal ultrasound imaging\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAt the end of the 8-week intervention, we measured the thickness of the patellar tendon in the subjects using an ultrasound device, which was performed in the same way as at baseline, see \u003cstrong\u003eFigure 6.\u003c/strong\u003e Some subjects were unable to participate in the last musculoskeletal ultrasound measurement for various reasons. The measurement results are shown in \u003cstrong\u003eTable 5\u003c/strong\u003e. The patellar tendon thickness in the combined and HSR groups exhibited a slight increase from baseline, yet this was not statistically significant. In contrast, the TUS group demonstrated a more pronounced and significant increase in patellar tendon thickness from baseline (p \u0026lt; 0.05). Comparative analysis of the three groups revealed no significant differences in tendon thickness before and after the intervention.\u0026nbsp;\u003c/p\u003e"},{"header":"7. Discussion","content":"\u003cp\u003eHeavy slow resistance training (HSR) and therapeutic ultrasound are commonly used in musculoskeletal disorder rehabilitation. While both are often used for patellar tendinopathy, using either alone may not be effective in some cases(\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e). Research shows that HSR training can increase collagen production in the tendon, leading to pain relief. However, this effect may be limited in individuals with severe squatting difficulties or intense pain during squatting (\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e). On the other hand, high-dose therapeutic ultrasound (TUS) can raise the tendon's internal temperature, promoting healing(\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). This study aimed to evaluate the effectiveness of combining HSR training with high-dose TUS for treating patellar tendinopathy, focusing on pain reduction, strength, athletic performance, and balance. The VISA-P score questionnaire results showed that participants in the HSR training group had an average improvement of 17 points compared to their baseline scores. In contrast, those in the TUS treatment group saw an average increase of 6 points, while participants in the combination group had an average improvement of 21 points. The study suggests that combining high-dose TUS with HSR training had a significant short-term positive effect on PT. For chronic PT cases, HSR training was more effective in reducing pain than high-dose TUS alone, which had limited pain-relief benefits. Although the high-dose TUS group showed statistically significant improvements in VISA-P scores post-intervention, these improvements did not reach the minimum clinically important difference (MCID) of 13 points for PT symptom improvement(\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e). In the 16th week, a follow-up was conducted with participants to collect their Visa-P score questionnaires. The VISA-P scores were 77.3\u0026thinsp;\u0026plusmn;\u0026thinsp;10.4 (ranging from 52 to 94) for subjects in the HSR training group, 74.0\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5 (ranging from 63 to 84) for subjects in the TUS treatment group, and 82.8\u0026thinsp;\u0026plusmn;\u0026thinsp;6.2 (ranging from 74 to 92) for subjects in the combined group. The results showed that the combined group and HSR group demonstrated more sustained improvements after the intervention ended, while the TUS group experienced a significant decrease in treatment effectiveness post-intervention. This suggests that in clinical settings using ultrasound therapy for patellar tendon disease, attention should be given to the continuity of treatment. Further research is needed to determine the duration of treatment necessary for the tendon to undergo adaptive changes, as indicated in the supplementary data. Our study utilized a TUS dosage of 4920 joules; however, due to limited research on the optimal TUS dosage for tendinopathy treatment, it is possible that the lower dosage parameters used may not have been adequate to generate significant clinical effects.\u003c/p\u003e \u003cp\u003eOur hypothesis was that the combined group would exhibit more significant improvements in standing jump distance post-training, given that patellar tendinopathy (PT) is commonly associated with pain during jumping and landing(\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e). However, the results showed considerable variability, with no significant differences noted between pre- and post-intervention assessments (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05). This variability could be due to the focus of high-speed resistance (HSR) training on eccentric and concentric contractions, which may not fully align with the explosive nature of vertical jumps. Moreover, all three experimental groups demonstrated significant improvements in balance abilities, particularly the Combined group, suggesting the potential benefits of HSR training in enhancing dynamic stability and balance by improving muscle control over postural changes. In contrast, therapeutic ultrasound therapy, a common physical therapy modality, primarily relies on thermal and mechanical effects to aid tissue repair and regeneration. While previous studies have shown some therapeutic effects of ultrasound therapy on certain musculoskeletal conditions, its impact on balance abilities remains inadequately studied and confirmed. Some participants initially reported pain hindering their performance in the Y-Balance Test (YBT) during baseline measurements, but this hindrance notably decreased after 8 weeks of intervention. Hence, the improvement in balance abilities among the therapeutic ultrasound (TUS) group participants may be linked to pain relief. However, further research and discussion are necessary to explore the influence of pain on test outcomes. Further research and discussion are needed to explore the impact of pain on test results. Future studies could delve into the potential influence of pain on balance abilities and the effectiveness of different intervention methods in pain regulation.\u003c/p\u003e \u003cp\u003eHSR training significantly contributed to the improvement of quadriceps flexibility, whereas the ultrasound group showed limited improvements. This difference is likely attributed to the specific exercises chosen. These findings suggest that resistance training offers notable benefits for enhancing muscle flexibility, as it can enhance flexibility by modifying the length-tension relationship of muscles and the adaptability of the nervous system(\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e). The closed-chain lower limb exercises we utilized not only directly impact the muscles but also influence the entire lower limb movement pattern, potentially modifying the flexibility of the quadriceps. However, the question of whether the alteration in lower limb movement patterns primarily contributes to the enhancement of quadriceps femoris flexibility, or if the improvement in quadriceps femoris flexibility predominantly induces changes in lower limb movement patterns, remains a topic that necessitates further investigation. Subsequent research endeavors could delve into thoroughly examining the causal relationship between the improvement in quadriceps femoris flexibility and alterations in lower limb movement patterns. Through the implementation of more sophisticated research methodologies and biomechanical analyses, a more comprehensive understanding of the reciprocal influence mechanisms between muscle flexibility and movement patterns can be attained.\u003c/p\u003e \u003cp\u003eThe study found a significant increase in the maximum isometric strength of participants, offering valuable insights into the performance of both the combined and training groups in terms of strength improvement. This information is particularly beneficial for high-level athletes during their competitive season. The combined group showed a 42% increase compared to pre-intervention levels, while the training group saw a 30% increase, suggesting multiple factors may have contributed to this growth. The rise in strength can be partially attributed to neuromuscular adaptation effects. Through strength training, muscle tissue undergoes various adaptive changes, such as increased muscle fibers and enhancements in the nervous system, which enable muscles to generate force more efficiently. These findings align with previous research indicating that prolonged training can enhance muscle strength(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e). For in-season athletes, the use of a combined intervention program can both reduce pain and maintain muscle strength to ensure good athletic performance.\u003c/p\u003e \u003cp\u003eIn the study of electromyographic signals, an interesting phenomenon was observed in in-season athletes undergoing a combined intervention program. After 8 weeks of biomechanical tests, it was noted that nearly all subjects experienced a decrease in electromyographic signals in the anterior muscles, specifically the vastus medialis obliquus (VMO) and vastus lateralis obliquus (VLO), during single-leg squats. Moreover, there was a varied reduction in the VMO/VLO ratio. The interpretation suggests that the reduction in pain led to an enhancement in the patellar tendon's mechanical transmission capacity. This improvement in mechanical transmission led to a notable decrease in the quadriceps' workload during the single-leg squat, as evidenced by a decline in EMG signals. Additionally, the decrease in the VMO/VLO ratio indicates a reduction in knee valgus and hip adduction angles during squatting post-intervention, possibly due to pain relief influencing lower limb movement strategies and joint kinematics to some extent. Further research is necessary to elucidate the impact of patellar tendon pain on lower limb movement strategies in athletes with patellar tendinopathy(\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e). Additional research is needed to clarify the effects of patellar tendon pain on lower limb movement strategies among athletes with patellar tendinopathy.\u003c/p\u003e \u003cp\u003eThe results of patellar tendon color Doppler ultrasonography in the subjects demonstrated a notable reduction in blood flow within the tendon following an 8-week exercise intervention compared to pre-intervention. This finding is in line with the outcomes of Koenig et al.'s research(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e). Exercise intervention may facilitate the normalization of blood vessel distribution around the tendon, diminish the formation of abnormal vessels within the patellar tendon, and lower the concentration of specific neurotransmitters in the tendon blood vessels, (\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e) potentially contributing to the decrease in pain levels observed in the subjects. Regarding changes in patellar tendon thickness, participants in all three groups displayed varying degrees of increased thickness post the 8-week intervention period(\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e). Nonetheless Kongsgaard et al.'s study(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e) noted a significant 45% decrease in tendon thickness among subjects in the HSR exercise group by week 12, approaching the original fiber morphology of healthy tendons(\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). It is possible that between the 8th and 12th weeks post-intervention, the tendons underwent adaptive changes, resulting in a reduction in thickness for tendons that initially thickened during the early intervention period. Agergaard et al.(\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e) conducted musculoskeletal ultrasound measurements of patellar tendons in two high-speed resistance exercise intervention groups at baseline, 6 weeks, 12 weeks, and 52 weeks. They observed an initial increase in tendon thickness in both groups from baseline to 6 weeks, followed by a decrease in tendon thickness from 6 to 12 weeks, which aligns with our initial hypothesis. However, it is important to acknowledge that variations in the ultrasound measurement techniques utilized could also contribute to discrepancies in results. Future studies should consider employing standardized musculoskeletal ultrasound measurements. Tsai et al. (\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e) proposed that extracorporeal ultrasound may facilitate tendon healing, although the specific mechanisms underlying this process remain unclear. Our research demonstrated a significant increase in patellar tendon thickness among participants receiving extracorporeal high-energy dose ultrasound therapy after an 8-week intervention, compared to baseline measurements. As we did not perform ultrasound assessments at the 12-week mark, the potential impact of extended extracorporeal ultrasound intervention on tendon thickness remains unknown. In summary, we hypothesize that damaged tendons undergo a thickening process during recovery towards a healthy tendon structure, possibly due to the formation of new scar tissue. Further comprehensive investigations are warranted to elucidate the precise timeline of scar tissue development and resolution within the tendon.\u003c/p\u003e \u003cp\u003eThe majority of participants adhered to a supervised exercise program three times a week, a key strength of the experiment. The subjects' training and rest periods were closely monitored to ensure completion of the program. All participants underwent follow-up assessments after 16 weeks in a controlled environment at designated facilities to minimize external interference. The study included university student athletes from Wuhan Sports University, providing a reasonably representative research population. However, the study has several limitations that should be considered in future research. The intervention instructors were not blinded, potentially impacting outcomes. To address this, additional training was provided to ensure consistent execution of exercises and communication of experimental details with participants was minimized. Participants engaged in various sports disciplines, and although encouraged to limit unrelated physical activities during the 8-week intervention, some may have still engaged in other sports, potentially affecting results. Kinematic evaluation involved participants squatting on an inclined platform before and after the intervention. During baseline testing, a small number of participants experienced patellar tendon pain when attempting to lower their bodies to the specified angle. For safety reasons, we allowed these participants to rise after reaching the maximum angle they could tolerate. It is important to highlight that in the post-8-week test, all participants successfully squatted to the specified angle, potentially leading to an increased risk of Type I errors. Additionally, our follow-up with participants only extended to 16 weeks, limiting our ability to assess the long-term effectiveness of exercise intervention on patellar tendon diseases. Further research is needed to explore the efficacy of exercise intervention in addressing this aspect.\u003c/p\u003e \u003cp\u003eOur research findings indicate that the combination of Heavy Slow Resistance training and high-dose ultrasound therapy leads to substantial improvements in pain and functionality for patients with patellar tendinopathy. This combined approach is particularly effective in reducing symptoms in chronic patients, making it a suitable protocol for individuals with severe symptoms or those seeking improved athletic performance.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eBF\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eBiceps femoris\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eESWT\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eExtracorporeal shockwave therapy\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eEET\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eEccentric exercise training\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eEMG\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eElectromyography\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eHSR\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eHeavy slow resistance\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eMTT\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eModified Thomas Test\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eMVIC\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eMaximum Voluntary Isometric Contraction\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eMIMS\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eMaximal isometric muscle strength\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eRMS\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eRoot mean square\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eTLT\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eTendon-loading training\u003cstrong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eTUS\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eTherapeutic ultrasound\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eVAS\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eVisual Analogue Scale\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eVISA-P\u003c/em\u003e\u003c/strong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eVictorian Institute of Sport Assessment-Patella\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eVLO\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eVastus lateralis obliquus\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eVMO\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003eVastus medialis obliquus\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePT\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003ePatellar tendinopathy\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eYBT\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cem\u003e：\u003c/em\u003e\u003c/strong\u003e Y-Balance Test\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003edeclaration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experimental protocol was established, according to the ethical guidelines of the Helsinki Declaration and was approved by the Human Ethics Committee of Wuhan Sports University. Written informed consent was obtained from individual or guardian participants\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed consent form\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePrior to the start of the experiment, informed consent forms should be provided, requiring participants to know the specific protocol and risks of the experiment, and to sign informed consent forms after understanding the protocol.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study is not funded.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article (and Additional file 1\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe extend our gratitude to the Wuhan Sports University for providing the intervention site for this experiment and to all the subjects and staff who participated in this experiment.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eScott A, Squier K, Alfredson H, Bahr R, Cook JL, Coombes B, et al. 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Am J Phys Med Rehabil. 2011;90(12):1068-73.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable\u0026nbsp;1 Therapeutic ultrasound (TUS) dosimetric parameters\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003eParameters\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003eAdjusts\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003eFrequency\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003e1MHZ\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003eMode\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003eContinuous\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003e10min\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003eEnergy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003e4920J / per application\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003eEffective radiation area\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003e5.5cm\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eTable 2 the features of the subjects.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"548\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.120658135283364%\" valign=\"top\"\u003e\n \u003cp\u003eCombined group\u003c/p\u003e\n \u003cp\u003e(N=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003eHSR group\u003c/p\u003e\n \u003cp\u003e(N=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003eTUS group\u003c/p\u003e\n \u003cp\u003e(N=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.904936014625228%\" valign=\"top\"\u003e\n \u003cp\u003eP-Value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003eAge (yrs)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.120658135283364%\" valign=\"top\"\u003e\n \u003cp\u003e21.41\u0026plusmn;1.46(19-24)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e22.12\u0026plusmn;1.616 (19-25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e21\u0026plusmn;1.458(19-24)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.904936014625228%\" valign=\"top\"\u003e\n \u003cp\u003e＞0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003eHeight (m)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.120658135283364%\" valign=\"top\"\u003e\n \u003cp\u003e1.785\u0026plusmn;0.080 (1.65-1.92)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e1.812\u0026plusmn;0.055 (1.70-1.90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e1.799\u0026plusmn;0.081 (1.67-1.92)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.904936014625228%\" valign=\"top\"\u003e\n \u003cp\u003e＞0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003eWeight(kg)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.120658135283364%\" valign=\"top\"\u003e\n \u003cp\u003e71.65\u0026plusmn;11.20 (55-95)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e76.35\u0026plusmn;7.911 (63-90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e75.66\u0026plusmn;14.01 (55-102)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.904936014625228%\" valign=\"top\"\u003e\n \u003cp\u003e＞0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e )\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.120658135283364%\" valign=\"top\"\u003e\n \u003cp\u003e22.38\u0026plusmn;2.190 (19.03-26.81)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e23.22\u0026plusmn;1.574 (19.44-25.76)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e23.23\u0026plusmn;2.909 (17.36-28.37)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.904936014625228%\" valign=\"top\"\u003e\n \u003cp\u003e＞0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003eSymptom duration (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.120658135283364%\" valign=\"top\"\u003e\n \u003cp\u003e7.235\u0026plusmn;5.203(3-24)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e16.76\u0026plusmn;18.72(3-70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e9.176\u0026plusmn;7.00(3-24)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.904936014625228%\" valign=\"top\"\u003e\n \u003cp\u003e＞0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003eGender (male/female)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.120658135283364%\" valign=\"top\"\u003e\n \u003cp\u003e14/3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e17/0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e15/2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.904936014625228%\" valign=\"top\"\u003e\n \u003cp\u003e＞0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003ePrimary sport\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.120658135283364%\" valign=\"top\"\u003e\n \u003cp\u003e4 Soccer\u003c/p\u003e\n \u003cp\u003e6 Running\u003c/p\u003e\n \u003cp\u003e2 Basketball\u003c/p\u003e\n \u003cp\u003e3 Table Tennis\u003c/p\u003e\n \u003cp\u003e1 Unknown\u003c/p\u003e\n \u003cp\u003e1 Fitness\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e3 Gymnastics\u003c/p\u003e\n \u003cp\u003e4 Tennis\u003c/p\u003e\n \u003cp\u003e4 Badminton\u003c/p\u003e\n \u003cp\u003e5 Basketball\u003c/p\u003e\n \u003cp\u003e2 Unknown\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.6581352833638%\" valign=\"top\"\u003e\n \u003cp\u003e3 Fitness\u003c/p\u003e\n \u003cp\u003e3 Golf\u003c/p\u003e\n \u003cp\u003e4 Basketball\u003c/p\u003e\n \u003cp\u003e1 Badminton\u003c/p\u003e\n \u003cp\u003e3 Fitness\u003c/p\u003e\n \u003cp\u003e2 Running\u003c/p\u003e\n \u003cp\u003e1 Unknown\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.904936014625228%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable\u0026nbsp;3\u0026nbsp;Changes in selected indicators before and after intervention\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003eCombined group\u003c/p\u003e\n \u003cp\u003e(N=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003eHSR group\u003c/p\u003e\n \u003cp\u003e(N=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003eTUS group\u003c/p\u003e\n \u003cp\u003e(N=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003eP-Value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eVAS-△0w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e6.794\u0026plusmn;1.552\u003c/p\u003e\n \u003cp\u003e(3-9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e6.971\u0026plusmn;1.494\u003c/p\u003e\n \u003cp\u003e(5-10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e6.647\u0026plusmn;1.183\u003c/p\u003e\n \u003cp\u003e(5-9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.8021\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eVAS-△8w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e2.059\u0026plusmn;0.9334\u003c/p\u003e\n \u003cp\u003e(1-4)**\u003csup\u003e＆△△\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e2.882\u0026plusmn;1.139\u003c/p\u003e\n \u003cp\u003e(1-5)**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e3.294\u0026plusmn;0.8671\u003c/p\u003e\n \u003cp\u003e(2-5)**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.0023\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eYBT-△0w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e0.8778\u0026plusmn;0.07586\u003c/p\u003e\n \u003cp\u003e(0.7343-0.9883)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e0.9290\u0026plusmn;0.07846\u003c/p\u003e\n \u003cp\u003e(0.7828-1.025)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e0.9160\u0026plusmn;0.07203\u003c/p\u003e\n \u003cp\u003e(0.7913-1.019)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.1319\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eYBT-△8w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e0.9669\u0026plusmn;0.0772\u003c/p\u003e\n \u003cp\u003e(0.8238-1.060)**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e0.9917\u0026plusmn;0.06974\u003c/p\u003e\n \u003cp\u003e(0.8655-1.097)**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e0.9595\u0026plusmn;0.07888\u003c/p\u003e\n \u003cp\u003e(0.8046-1.091)**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.4337\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eMTT-△0w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e51.55\u0026plusmn;1.303\u003c/p\u003e\n \u003cp\u003e(50.0-55.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e51.72\u0026plusmn;2.152\u003c/p\u003e\n \u003cp\u003e(49.0-55.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e52.35\u0026plusmn;1.868\u003c/p\u003e\n \u003cp\u003e(49.8-56.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.4046\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eMTT-△8w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e54.84\u0026plusmn;1.703\u003c/p\u003e\n \u003cp\u003e(52.2-58.2)**\u003csup\u003e△\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e54.39\u0026plusmn;2.218\u003c/p\u003e\n \u003cp\u003e(51.1-58.3)**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e52.77\u0026plusmn;1.966\u003c/p\u003e\n \u003cp\u003e(50.7-57.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.0092\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eMIMS-△0w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e216.7\u0026plusmn;56.03\u003c/p\u003e\n \u003cp\u003e(118.0-308.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e254.4\u0026plusmn;36.91\u003c/p\u003e\n \u003cp\u003e(201.5-353.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e235.6\u0026plusmn;46.11\u003c/p\u003e\n \u003cp\u003e(161.0-322.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.0747\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eMIMS-△8w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e295.4\u0026plusmn;73.63\u003c/p\u003e\n \u003cp\u003e(157.0-432.5)**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e326.7\u0026plusmn;78.78\u003c/p\u003e\n \u003cp\u003e(194.5-494.0)**\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e282.4\u0026plusmn;90.27\u003c/p\u003e\n \u003cp\u003e(169.5-476.5)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.2724\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eHorizontal Jump-△0w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e225.3\u0026plusmn;25.65\u003c/p\u003e\n \u003cp\u003e（170-275）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e231.1\u0026plusmn;22.91\u003c/p\u003e\n \u003cp\u003e（189-266）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e229.5\u0026plusmn;32.09\u003c/p\u003e\n \u003cp\u003e（170-286）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.8131\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.45945945945946%\" valign=\"top\"\u003e\n \u003cp\u003eHorizontal Jump-△8w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.44144144144144%\" valign=\"top\"\u003e\n \u003cp\u003e232.1\u0026plusmn;18.00\u003c/p\u003e\n \u003cp\u003e（197-255）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.34234234234234%\" valign=\"top\"\u003e\n \u003cp\u003e231.3\u0026plusmn;21.53\u003c/p\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"109\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\"\u003e\n \u003cp\u003e（194-262）\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.26126126126126%\" valign=\"top\"\u003e\n \u003cp\u003e231.1\u0026plusmn;27.09\u003c/p\u003e\n \u003cp\u003e（180-282）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.495495495495495%\" valign=\"top\"\u003e\n \u003cp\u003e0.9916\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eValues are means \u0026plusmn; SD\u003c/p\u003e\n\u003cp\u003eValues in brackets are range\u003c/p\u003e\n\u003cp\u003e**Siginificantly different from 0 week (p＜0.01)\u003c/p\u003e\n\u003cp\u003e*Significantly different from 0 week(p＜0.05)\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e△\u003c/sup\u003eSignificantly different from TUS group(p＜0.05)\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e△△\u003c/sup\u003eSignificantly different from TUS group(p＜0.01)\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e＆\u003c/sup\u003eSignificantly different from HSR group(p＜0.05)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable\u0026nbsp;4\u0026nbsp;Changes in VMO/VLO after 8 weeks of intervention\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"548\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.304189435336976%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.404371584699454%\" valign=\"top\"\u003e\n \u003cp\u003eCombined group\u003c/p\u003e\n \u003cp\u003e(N=15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.94353369763206%\" valign=\"top\"\u003e\n \u003cp\u003eHSR group\u003c/p\u003e\n \u003cp\u003e(N=14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.94353369763206%\" valign=\"top\"\u003e\n \u003cp\u003eTUS group\u003c/p\u003e\n \u003cp\u003e(N=15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.561020036429872%\" valign=\"top\"\u003e\n \u003cp\u003eF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.843351548269581%\" valign=\"top\"\u003e\n \u003cp\u003eP-Value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.304189435336976%\" valign=\"top\"\u003e\n \u003cp\u003eVMO/VLO-△0w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.404371584699454%\" valign=\"top\"\u003e\n \u003cp\u003e1.3\u0026plusmn;0.55\u003c/p\u003e\n \u003cp\u003e（0.84-2.7）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.94353369763206%\" valign=\"top\"\u003e\n \u003cp\u003e1.3\u0026plusmn;0.85\u003c/p\u003e\n \u003cp\u003e（0.53-3.7）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.94353369763206%\" valign=\"top\"\u003e\n \u003cp\u003e1.2\u0026plusmn;0.60\u003c/p\u003e\n \u003cp\u003e（0.68-2.9）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.561020036429872%\" valign=\"top\"\u003e\n \u003cp\u003e0.09\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.843351548269581%\" valign=\"top\"\u003e\n \u003cp\u003e0.9064\u003c/p\u003e\u0026nbsp;\u0026nbsp;\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"17.304189435336976%\" valign=\"top\"\u003e\n \u003cp\u003eVMO/VLO-△8w\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.404371584699454%\" valign=\"top\"\u003e\n \u003cp\u003e0.93\u0026plusmn;0.19\u003c/p\u003e\n \u003cp\u003e（0.64-1.3）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.94353369763206%\" valign=\"top\"\u003e\n \u003cp\u003e0.94\u0026plusmn;0.23\u003c/p\u003e\n \u003cp\u003e（0.58\u0026plusmn;1.5）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.94353369763206%\" valign=\"top\"\u003e\n \u003cp\u003e1.0\u0026plusmn;0.21\u003c/p\u003e\n \u003cp\u003e（0.66-1.3）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.561020036429872%\" valign=\"top\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.843351548269581%\" valign=\"top\"\u003e\n \u003cp\u003e0.5907\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eValues are means \u0026plusmn; SD\u003c/p\u003e\n\u003cp\u003eThere was no significant difference between the groups before and after the intervention.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 5 Changes in patellar tendon thickness after 8 weeks of intervention\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/132203_cef980177e9a226b/132203_custom_files/img1720544137.png\" width=\"748\" height=\"306\"\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eValues are means \u0026plusmn; SD\u003c/p\u003e\n\u003cp\u003eThere was no significant difference between the groups before and after the intervention.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-sports-science-medicine-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ssmr","sideBox":"Learn more about [BMC Sports Science, Medicine and Rehabilitation](http://bmcsportsscimedrehabil.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ssmr/default.aspx","title":"BMC Sports Science, Medicine and Rehabilitation","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"patellar tendinopathy, heavy slow resistance, therapeutic ultrasound, efficiency, exercise","lastPublishedDoi":"10.21203/rs.3.rs-4602813/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4602813/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003ePatellar tendinopathy (PT) is a common sports-related injury that often recurs. Heavy Slow Resistance Training (HSR) and High-Dose Therapeutic Ultrasound (TUS) are commonly used to treat PT. However, there is a lack of research on the combined effectiveness of these treatments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eIn this study, fifty-one college students aged 18 to 25, diagnosed with patellar tendinopathy using musculoskeletal ultrasound, were randomly assigned to three groups: a Combined HSR and high-dose TUS treatment group (n=17), an HSR training group (n=17), and a high-dose TUS treatment group (n=17). The intervention lasted for 8 weeks and various assessments were conducted including the Victorian Institute of Sport Assessment-Patella (VISA-P), Visual Analogue Scale (VAS), Y-balance Test (YBT), Modified Thomas Test (MTT), Horizontal Jumping Distance, Maximum Isometric Muscle Strength Test, musculoskeletal ultrasound for patellar tendon thickness and blood flow, and electromyography (EMG) of lower extremity muscles. Results showed significant improvement in knee joint function across all intervention methods, with the Combined group showing the most improvement. Follow-up at week 16 indicated continued improvement in VISA-P scores for the Combined and HSR groups, while a decrease was observed in the TUS group. Compared to pre-intervention, all groups showed significant differences in post-intervention VAS scores (p \u0026lt; 0.01), indicating a reduction in pain. While no significant differences in VAS scores were present among groups pre-intervention, post-intervention results revealed significant differences between the Combined and HSR groups (p \u0026lt; 0.05), as well as between the Combined and TUS groups (p \u0026lt; 0.01). The MTT test demonstrated notable improvements in joint mobility and quadriceps flexibility in the Combined and HSR groups after the 8-week intervention (p \u0026lt; 0.01), with no significant changes observed in the TUS group. Inter-group comparisons did not show significant differences both before and after the intervention. YBT test results also indicated significant differences.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e Both exercise intervention and high-dose TUS can moderately decrease pain and improve motor capacity in patients with patellar tendinopathy. However, the therapeutic effect of high-dose TUS alone is relatively limited compared to exercise intervention. The combined application of both methods results in the most significant improvement in pain relief and motor function enhancement. The trial was registered on ISRCTN11447397 (www.ISRCTN.com) on 17/02/2024（Retrospectively registered）.\u003c/p\u003e","manuscriptTitle":"Comprehensive Assessment of Heavy Slow Resistance Training and High-Dose Therapeutic Ultrasound in Managing Patellar Tendinopathy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-18 16:05:24","doi":"10.21203/rs.3.rs-4602813/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-06-20T12:23:54+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-20T10:47:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-06-20T00:54:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Sports Science, Medicine and Rehabilitation","date":"2024-06-19T03:14:22+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-sports-science-medicine-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ssmr","sideBox":"Learn more about [BMC Sports Science, Medicine and Rehabilitation](http://bmcsportsscimedrehabil.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ssmr/default.aspx","title":"BMC Sports Science, Medicine and Rehabilitation","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"298fac9f-6093-49a6-acca-3f9d89f7c60a","owner":[],"postedDate":"July 18th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-14T15:59:20+00:00","versionOfRecord":{"articleIdentity":"rs-4602813","link":"https://doi.org/10.1186/s13102-024-01004-2","journal":{"identity":"bmc-sports-science-medicine-and-rehabilitation","isVorOnly":false,"title":"BMC Sports Science, Medicine and Rehabilitation"},"publishedOn":"2024-10-10 15:57:04","publishedOnDateReadable":"October 10th, 2024"},"versionCreatedAt":"2024-07-18 16:05:24","video":"","vorDoi":"10.1186/s13102-024-01004-2","vorDoiUrl":"https://doi.org/10.1186/s13102-024-01004-2","workflowStages":[]},"version":"v1","identity":"rs-4602813","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4602813","identity":"rs-4602813","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}