Evaluation of different squatting modes in the rehabilitation of patellofemoral pain syndrome: A prospective randomized controlled trial

Evaluation of different squatting modes in the rehabilitation of patellofemoral pain syndrome: A prospective randomized controlled trial | 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 Evaluation of different squatting modes in the rehabilitation of patellofemoral pain syndrome: A prospective randomized controlled trial Hao-Ran Li, Zi-Mu Fan, Tao Huang, Yue-Yang Hou, Jian-Li Gao, Yan-Bing Zhang, and 7 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6196818/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background : Static squats are widely used in the treatment of patellofemoral pain syndrome (PFPS), but no study has determined the most effective static squat mode. This study compared the efficacies of three static squat modes in the rehabilitation of patients with PFPS. Methods : This studyrecruited 84 patients with PFPS who were divided into four groups on the basis of different static squat modes. The patients underwent a 6-week training period using a mobile phone app equipped with angle recognition function. Treatment efficacy was assessed using the Kujala, Lysholm, VAS-W, and VAS-U scores, as well as the thigh circumference, peak torque of knee extension, and peak torque of knee flexion on the affected side. Intra- and intergroup differences were analyzed using two-way analysis of variance. Moreover, a paired-sample t-test and one-way analysis of variance were applied for intergroup comparisons. Chi-square tests were performed on categorical data. Results : Wall squats assisted by elastic bandssignificantly differed from the control in terms of the Kujala, Lysholm, VAS-W, and VAS-U scores (P < 0.05). Thigh circumference and peak torque of knee extension in isokinetic muscle strength tests were normally distributed and had homogeneous variance. Conclusion : Wall squats can effectively improve patellofemoral joint function and alleviate pain. This study aids the home rehabilitation of patients with PFPS. Registration number: M2023013 Patellofemoral pain syndrome Static squat Rehabilitation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Static squat is widely used in the treatment of various lower limb diseases. It can reduce pain and resting blood pressure [ 1 , 5 ], increase strength and volume of the deep abdominal muscles [ 2 ], and improve posture [ 3 ] and stability of the waist [ 4 ]. The commonly used modes of static squat in clinical practice are wall squat, direct squat, ball squat, and wall squat assisted by elastic bands. Each mode of static squat stimulates the quadriceps, hamstring, and multifidus muscles differently [ 6 ]. However, the static squat mode that most effectively facilitates the rehabilitation of patients with patellofemoral pain syndrome (PFPS) remains to be studied. The force exerted on the patellofemoral joint (PFJ) is closely related to the angle of knee flexion, the distance between the heel and the wall, and the load-bearing capacity of one or both of the lower limbs. Among these factors, the distance between the heel and the wall is a particularly crucial determinant of the pressure on the PFJ [ 7 ]. The distance between the heel and the wall decreases while executing a wall squat, requiring the knee joint to bend a certain angle, which may result in the knee extending beyond the tips of the toes. For the same knee flexion angle, the pressure on the PFJ is higher during any movement wherein the knee extends beyond the toe tips compared with when it does not [ 8 ]. Moreover, the pressure on the PFJ is higher when squatting at the same angle with one leg compared with both the legs. Studies on static squats have measured the degree of muscle activation in the lower limbs using surface electromyography [ 9 ]. Studies have indicated that static squats can not only stimulate the quadriceps and hamstring muscles but also the triceps, gluteus, abdominal, and multifidus muscles [ 2 , 6 , 10 ]. The quadriceps is the muscle group most closely related to PFPS. Ziyue Hu et al. discovered that the values of the surface electromyography parameters of the quadriceps continuously increased with knee flexion angle during static squatting. In the last stage of a static squat, when the vastus lateralis become fatigued, the discharge of the vastus medialis increases and the discharge of the rectus femoris subsequently increases, which suggests that training the vastus medialis and vastus lateralis first would be conducive to enhancing the strength of the quadriceps. Yu Wang et al. found by measuring the degree of muscle activation and patellofemoral joint force at different static squatting angles, when the angle set at 45°, comparing with 30°and 60°, quadriceps get tired more easily, the exercise is more effective. It is the appropriate angle for static squat exercise between 30°and 60°.(Table 1 ) Comparing with the research of Yu Wang and Ziyue Hu, it is found that the activation of muscle by squatting against the wall is more effective than direct squat.[ 11 ] Table 1 Quadriceps iEMG at different static squatting angles (mV·s − 1 ) Angle Vastus lateralis Rectus femoris Vastus medialis 30° 66.67 ± 13.91 43.44 ± 10.80 56.44 ± 11.00 45° 77.08 ± 9.00 52.70 ± 9.88 64.77 ± 9.38 60° 75.25 ± 15.08 52.07 ± 14.29 61.56 ± 14.22 Natelie Golding et al. adjusted wall squat intensity and explored the cardiovascular responses, they have found thatthe wall squat elicited similar cardiovascular responses to other isometric exercise modes that have reduced resting blood pressure, may have a useful role to play in isometric training aimed at reducing resting blood pressure.[ 12 ] The authors think that, compared with direct static squat, squat against the wall under the support of the wall is relatively easy to perform, which requires less stability of the human body, can reduce the resting blood pressure, and has less requirements for breathing and oxygen uptake. Therefore, squatting against the wall is a more appropriate training method. There’s no study verify that opinion. Mobile health—the use of mobile apps to facilitate rehabilitation exercises at home—is defined by the World Health Organization as the use of any mobile device, such as wearable monitoring devices, for obtaining medical or public health support [ 13 ]. This study used a new remote rehabilitation movement recognition system, which can effectively determine the angle of knee flexion during static squatting. This measurement method was demonstrated to be accurate and first established in 2019 by Aditya et al., who used a simple mobile phone camera and an observation system based on the OpenPose algorithm without relying on peripheral equipment (e.g., wearable sensors and wristbands) to determine the angle of knee flexion and extension [ 14 ]. This study explored the efficacy and therapeutic effects of three modes of static squats in patients with PFPS. The broader objective was to aid the application of mobile health to the home rehabilitation of patients with PFPS. 2. Methods This study is a prospective randomized controlled trial investigating the efficacy of different static squat modes in the rehabilitation of patients with PFPS. The study protocol was registered on the Protocol Registration and Results System ( https://register.clinicaltrials.gov/ , identification number: NCT06592898 ) 2.1 Participants A random sample of 84 patients were screened from among all patients in Peking University Third Hospital and Chongli Branch from January 2023 to September 2023. The recruited patients were randomly assigned to either the experimental groups or the control group, with 21 participants per group. This study was approved by the Ethics Committee of Peking University Third Hospital (M2023013). All the participants provided their written informed consent. 2.2 Inclusion criteria Individuals were included in this study if (1) they met the diagnostic criteria of PFPS; (2) they were aged 20–45 years old, to reduce the risk of osteoarthritis affecting the PFJ [ 15 ]; (3) they were not on any treatment regimen before the experiment; and (4) they had provided signed informed consent. 2.3 Exclusion criteria Individuals were excluded from this study if (1) they had already had surgery; (2) they had other lower limb injuries, such as meniscus tear, bursitis, ligament injury, patellar tendon injury, or joint degeneration; (3) they had a history of patellofemoral dislocation and subluxation; (4) they had cardiovascular or cerebrovascular diseases, lung disease, kidney disease, or other prominent visceral diseases; (5) they were cognitively impaired and unable to use mobile apps. 2.4 Instrument The participants were assessed by the same researcher using the Biodex isokinetic muscle strength tester (Biodex, New York, USA) at baseline and 6 weeks after the intervention (Fig. 1 ). Both knee joints of the participants were assessed, and the isokinetic muscle force test was performed at an angular velocity of 60° per second. Participants who reported pain in both their PFJs were subjected to indicator analysis. Pain is most severe at the peak moment of knee flexion and extension of the lower limb. Data on each indicator were collected, recorded into Microsoft Excel, and summarized. After all participants underwent the intervention, the data in Excel were transferred into SPSS 26 software (IBM, New York, USA) for processing and analysis. The measurement data were subjected to normality and homogeneity of variance tests prior to statistical analysis. Results for variables with homogenous variance and a normal distribution are presented as the mean ± standard deviation. The participants’ Kujala scores, Lysholm scores, Visual Analog Scale for Worst pain (VAS-W) scores, and Visual Analog Scale for Usual pain (VAS-U) scores were analyzed using two-factor analysis of variance. 2.5 Research methods The 84 participants with PFPS were numbered according to the order of treatment. A randomized controlled trial was designed, comprising a control group and three experimental groups corresponding to three static squat modes. Movement quality was monitored using a mobile app (Yiyuetsu Technology, Beijing, China). The random number generator in SPSS 26.0 software was used to assign participants to one of the four groups, with 21 participants per group. VAS, scores on the anterior knee pain scale and Lysholm knee score scale, thigh circumference, and peak torque of knee extension were compared preintervention and postintervention to determine the optimal static squat mode. 2.6 Intervention methods for the control group The participants in the control group assumed a supine position with straight leg lift (Fig. 2 ). The other knee (of the leg that was not lifted) was at 90°, with the foot placed flat on the ground. The ankle was flexed to contract the quadriceps on the other side. The knee joint was then straightened, and the thigh was lifted for the hip to be at 30°. The heel was approximately 20 cm away from the ground. Finally, the leg was lowered to a resting position after 2 s. Ten repetitions of this action constituted a group. Each practice session had five groups, with a 1-minute rest between groups. Practice sessions were held five times a week and involved both legs. The participants were asked to breathe normally throughout without holding their breath. 2.7 Intervention methods for the experimental groups The three experimental groups corresponded to three modes of static squats: wall squat (group A), direct squat (group B), and wall squat assisted by elastic bands (group C). In group A, the participants’ upper body was upright, the distance between their feet was equivalent to the width of their shoulders, and their hands were placed on either side of the body or above the thighs. Their toe tips were toward the front and perpendicular to the wall. The distance between the wall and their heels was approximately a foot, their back was close to the wall, and the squat was performed slowly (Fig. 3 ). The angle of the wall squat ranged from 30° to 60°. The pressure on the PFJ is too high at angles exceeding 60°. Moreover, training at a large angle for a long time may lead to secondary injury of the knee joint [ 16 – 19 ]. The angle was set at 30° for the first 2 weeks, after which it was increased to 45° and finally set at 60° for the last 2 weeks. In group B, the participants stood on the flat ground with their upper body upright, the distance between their feet was equivalent to the width of their shoulders, and their toe tips were toward the front. Their trunk was adjusted forward according to the angle of static squat. The specific method included aligning the trunk with the shoulder joint and knee joint perpendicular to the ground. The knee joint can bend to a large angle [ 20 ]. The participants were asked to put their hands in front of their bodies, and their center of gravity was between their feet. The angle was set at 30° for the first 2 weeks, after which it was increased to 45° and finally set at 60° for the last 2 weeks. (Fig. 4 ) In group C, the participants performed wall squats but with an elastic band of 20 pounds wrapped around their thighs. They opened their thighs and feet at a low speed, so that the elastic bands were slightly deformed and they experienced an obvious resistance on the outside of their thighs. The angle was set at 30° for the first 2 weeks, after which it was increased to 45° and finally set at 60° for the last 2 weeks (Fig. 5 ). The duration of each squat mode was until the participants could no longer squat, and the exhaustion of muscle endurance marked the end point of the exercise. The rest time between practice sessions was 1 minute. The participants were required to squat five times a day for five days a week. The total study duration was 6 weeks, and the participants were followed up during the third week and sixth weeks. The subjective indicators were followed up by filling out the rating scale offline before intervention and during the third and sixth weeks of the intervention, so that the researchers could better explain the follow-up contents to the participants. The participants’ objective indicators were assessed before the intervention and after 6 weeks of the intervention. 2.8 Quality and compliance control The angle of static squat was determined using an artificial intelligence system on a mobile app and was used to indicate the quality of the participants’ static squat. The app sent training reminders to the participants at 1 pm and 8 pm every day. The researchers monitored the participants’ training status and duration on the app at 10 pm every day to stay up-to-date about the participants’ home rehabilitation progress. The researchers contacted participants who did not engage in training on WeChat or by telephone to encourage them to participate in training. 3. Results 3.1 General data on the participants A total of 84 participants were recruited in this study, divided into four groups by single-blind randomization (21 participants per group; Table 2 ) 3.2 Kujala score The Kujala scores of the control group were 71.67 ± 5.78, 73.24 ± 4.95, and 74.86 ± 4.87 at baseline, at 3 weeks, and at 6 weeks from the start of training, respectively. For these three time points, the Kujala scores of group A were 71.70 ± 8.73, 78.30 ± 6.61, and 85.95 ± 4.33, respectively; those of group B were 72.30 ± 5.44, 73.35 ± 5.53, and 73.15 ± 4.92, respectively; and of group C were 74.19 ± 6.76, 79.43 ± 6.23, and 82.86 ± 4.87, respectively. Table 2 Characteristics of the study sample Characteristics Group Control Group (n = 21) Group A (n = 20) Group B (n = 20) Group C (n = 21) P value Gender 0.84 Male 9 9 11 9 Female 12 11 9 12 Age 33.05 ± 5.30 37.30 ± 8.27 33.20 ± 7.91 34.43 ± 7.66 0.24 Height (cm) 170.00 ± 7.25 170.70 ± 8.93 169.90 ± 7.35 169.81 ± 8.04 0.98 Weight (kg) 65.14 ± 11.70 66.75 ± 13.19 63.45 ± 10.48 65.48 ± 9.93 0.84 Condition 0.96 Both 7 5 8 7 Left 8 9 6 7 Right 6 6 6 7 a Data on gender and condition of participants are presented in terms of frequency (number of people). Data on age, height, and weight are presented in terms of the mean ± standard deviation. 3.3 Lysholm scores The Lysholm scores of the control group were 74.95 ± 6.20, 74.90 ± 6.32, and 75.71 ± 6.03 at baseline, at 3 weeks, and at 6 weeks from the start of training, respectively. For these three time points, the Lysholm scores of group A were 73.20 ± 4.61, 73.60 ± 6.00, and 77.20 ± 5.25, respectively; those of group B were 74.60 ± 4.58, 75.10 ± 3.91, and 78.45 ± 5.01, respectively; and those of group C were 75.43 ± 5.30, 75.71 ± 6.19, and 82.52 ± 7.37, respectively. 3.4 VAS-W scores The VAS-W scores of the control group were 6.00 ± 1.05, 4.52 ± 1.44, and 3.52 ± 1.60 at baseline, at 3 weeks, and at 6 weeks from the start of training, respectively. For these three time points, the VAS-W scores of group A were 5.25 ± 1.37, 3.80 ± 1.06, and 2.60 ± 1.27, respectively; those of group B were 5.30 ± 1.38, 5.00 ± 0.97, and 4.80 ± 1.01, respectively; and those of group C were 5.29 ± 1.06, 3.29 ± 1.06, and 1.43 ± 1.16, respectively. 3.5 VAS-U scores The VAS-U scores of the control group were 4.10 ± 1.00, 3.81 ± 1.17, and 3.76 ± 0.94 at baseline, at 3 weeks, and at 6 weeks from the start of training, respectively. For these time points, the VAS-U scores of group A were 3.40 ± 1.05, 3.20 ± 1.20, and 2.25 ± 1.25, respectively; those of group B were 3.60 ± 1.27, 3.30 ± 1.34, and 3.30 ± 1.38, respectively; and those of group C were 3.57 ± 1.33, 2.86 ± 1.24, and 1.52 ± 1.12, respectively. 3.6 Thigh circumference The thigh circumferences of the control group before and after training were 46.09 ± 3.93 and 46.55 ± 3.71, respectively. For these two time points, the thigh circumferences of group A were 45.92 ± 2.97 and 47.02 ± 3.14, respectively, those of group B were 46.08 ± 2.52 and 47.03 ± 2.17, respectively, and of group C were 46.74 ± 3.82 and 48.82 ± 3.53, respectively. 3.7 Peak knee torque in isokinetic muscle strength test The peak knee torques in the control group before and after training were 78.25 ± 21.34 and 83.65 ± 16.38, respectively. For these two time points, the peak knee torques in group A were 74.89 ± 32.88 and 98.36 ± 33.84, respectively, those in group B were 76.64 ± 18.60 and 85.77 ± 19.64, respectively, and those in group C were 75.31 ± 19.57 and 101.8 ± 14.40, respectively. Table 3 Preintervention and postintervention results for comparison Group Control Group Group A Group B Group C p-value Kujala score before 71.67 ± 5.78 71.70 ± 8.73 72.30 ± 5.44 74.19 ± 6.76 0.59 3 weeks 73.24 ± 4.95 78.30 ± 6.61 a 73.35 ± 5.53 79.43 ± 6.23 a <0.05 6 weeks 74.86 ± 4.87 a 85.95 ± 4.33 ab 73.15 ± 4.92 82.86 ± 4.87 a <0.05 Lysholm score before 74.95 ± 6.20 73.20 ± 4.61 74.60 ± 4.58 75.43 ± 5.30 0.56 3 weeks 74.90 ± 6.32 73.60 ± 6.00 75.10 ± 3.91 75.71 ± 6.19 0.69 6 weeks 75.71 ± 6.03 77.20 ± 5.25 78.45 ± 5.01 82.52 ± 7.37 <0.05 VAS-W score before 6.00 ± 1.05 5.25 ± 1.37 5.30 ± 1.38 5.29 ± 1.06 0.15 3 weeks 4.52 ± 1.44 a 3.80 ± 1.06 a 5.00 ± 0.97 3.29 ± 1.06 a <0.05 6 weeks 3.52 ± 1.60 ab 2.60 ± 1.27 ab 4.80 ± 1.01 1.43 ± 1.16 ab <0.05 VAS-U score before 4.10 ± 1.00 3.40 ± 1.05 3.60 ± 1.27 3.57 ± 1.33 0.26 3 weeks 3.81 ± 1.17 3.20 ± 1.20 a 3.30 ± 1.34 2.86 ± 1.24 a 0.10 6 weeks 3.76 ± 0.94 2.25 ± 1.25 ab 3.30 ± 1.38 1.52 ± 1.12 a <0.05 Thighs circumference before 46.09 ± 3.93 45.92 ± 2.97 46.08 ± 2.52 46.75 ± 3.82 0.86 6 weeks 46.55 ± 3.71 47.01 ± 3.14 a 47.03 ± 2.17 a 48.82 ± 3.53 0.12 Peak torque of knee extension before 78.25 ± 21.34 74.89 ± 32.88 75.63 ± 18.60 75.31 ± 19.57 0.97 6 weeks 83.65 ± 16.38 a 98.36 ± 33.84 a 85.77 ± 19.64 a 101.85 ± 14.40 a <0.05 Peak torque of knee flexion before 37.38 ± 11.90 38.26 ± 19.37 38.55 ± 12.81 37.23 ± 9.32 0.99 6 weeks 37.81 ± 12.21 42.36 ± 21.03 54.50 ± 10.86 a 45.49 ± 10.83 a <0.05 a Data are presented as mean ± standard deviation b For thigh circumference score and peak torque of knee extension/flexion, a P denotes a comparison in the group with the corresponding values before intervention, a P < 0.05 c For Kujala, VAS-W, and VAS-U scores, a P denotes a comparison with the corresponding values before intervention, a P < 0.05, and b P denotes a comparison with the corresponding values at 3 weeks, b P < 0.05. 3.8 Peak knee moment in isokinetic muscle strength test The peak knee moments in the control group before and after training were 37.38 ± 11.90 and 37.81 ± 12.21, respectively. For these two time points, the peak knee moments in group A were 38.26 ± 19.37 and 42.36 ± 21.03, respectively; those in group B were 38.55 ± 12.81 and 54.50 ± 10.86, respectively; and those in group C were 37.23 ± 9.32 and 45.49 ± 10.83, respectively. 4. Discussion This prospective randomized controlled trial demonstrated that all three static squat modes effectively alleviated pain and improved PFJ function but to different extents. The central difference between a direct squat and a wall squat is in the pressure exerted on the PFJ. Wall squats can be divided into long versus short squats against the wall, according to the relative position of the knee joint and the toe. The knee joint is behind and in front of the toe tips in long and short squats against the wall, respectively. This study used the long squat against the wall. During direct squats, the knee joint easily exceeds the toe tips due to the center of gravity. The extension of the knee beyond the toe exerts high pressure on the PFJ, which may lead to the development of PFPS. The excessive pressure directly acts on the synovial fold, subpatellofemoral fat pad, support band, joint capsule, patellofemoral ligament, and subchondral bone [ 20 ]. Subchondral bone plates are filled with pain receptors; thus, increased subchondral bone stress caused by high patellofemoral pressure may also lead to PFPS [ 21 ]. Wen-Zhao Wang et al. investigated the Taichi horse stance and noted that this stance could be assumed using the normal trunk pattern (NTP) and the anteverted trunk pattern (ATP). The maximum range of hip joint flexion and extension under NTP is smaller than that under ATP. When the torso is kept straight, the pelvis rotates forward around the coronal axis, and the hip joint has a greater flexion amplitude when the human individual’s lower limb is in a closed chain stance. Studies have also indicated that the contact area between the femoral patellae increases with knee flexion angle, which helps distribute the pressure on the patella over a larger area, thereby mitigating contact stress and alleviating pain in patients with femoral patellae pain syndrome. The maximum knee angle under NTP was significantly smaller than that under ATP (i.e., the knee motion amplitude of the NTP was significantly larger than that of the ATP). In the aforementioned study of Wen-Zhao Wang et al., the individual assuming the NTP tried to maintain the position of the knee joint within the position of the toe, implying that the difference between NTP and wall squat may only lie in whether squatting against a wall dispersed the force on the knee joint during squatting, thereby relieving pain associated with PFPS. In addition, the direct squat used in this study was the same as ATP. The maximum knee angle of the NTP group was significantly smaller than that of the ATP group, thus reducing the contact stress of the knee joint to alleviate pain in patients with PFPS. Squatting against the wall seems to generate less pressure on the PFJ than squatting directly, which is more conducive to the rehabilitation treatment of patients with PFPS. The results of the present study also indicate that the final knee function score of the participants in the direct static squat group was worse than that of participants in the other groups, which may be related to the excessive pressure exerted on the PFJ [ 22 ]. 4.1 Limitations and future directions This study only focused on the clinical manifestations of patients with PFPS during static squatting training; it neither explored the contraction of muscles in each part of the lower extremities during the three static squatting modes nor evaluated the specific load exerted on the PFJ. Moreover, the duration of follow-up in this study was short, and no follow-up data were collected on whether the participants continued their training, whether pain recurred, or whether they resumed exercise. In addition, the intervention duration of this study was short, which precluded the possibility of determining the long-term efficacies of the three static squat modes in the rehabilitation of patients with PFPS. Future studies should explore the therapeutic differences between the different static squat modes from the perspectives of longer intervention and follow-up durations and the specific activation of lower limb and trunk muscles during static squat. Furthermore, the dose-response relationship of many traditional Chinese sports such as Tai chi and Taichi horse stance has not been studied systematically as aerobic exercise and resistance training, many important questions have not been answered. Such as how many hours should Tai Chi be practiced each time, and how many times a week? How many years can practicing Tai Chi add to your life? How much disease risk can be reduced? What is the mechanism of Tai Chi? What's the difference from cardio and strength training? 5. Conclusions This study aids the use of mobile health in the home rehabilitation of patients with PFPS. Patients with PFPS can train by performing wall squats or wall squats assisted by elastic bands, which can effectively improve PFJ function and reduce pain. Wall squat with elastic bands is the better choice of the two because it effectively stimulates the vastus medialis and vastus lateralis to alleviate pain. When patients with PFPS do not have any instruments accessible, they can train by performing wall squats. Direct squats are not a suitable exercise for patients with early PFPS; although direct squats can enhance muscle strength around the knee joint, they have limited benefits in improving PFJ function or alleviating PFJ pain. Abbreviations PFPS patellofemoral pain syndrome PFJ patellofemoral joint AKPS anterior knee pain scale LKSS lysholm knee score scale VAS visual analogue scale NTP normal trunk pattern ATP anteverted trunk pattern. Declarations Authors’ contributions Hao-Ran Li and Zi-Mu Fan are the primary designers of research. All authors have made suggestions for the research design and will be involved in the execution of the research. Funding Supported by the National Natural Science Foundation of China for mechanism of hydrogel with RP1 inhibitor in treatment of degenerative tendinopathy (82372449) and the Key Special Project of Peking University Third Hospital for comparing the clinical efficacy of Arthroscopic Lateral Retinacular Release and exercise therapy in the treatment of Lateral Patellar Compression Syndrome (BYSYDL2023013). Availability of data and materials The datasets used or analyzed during the current study are available from the corresponding author upon reasonable request. Ethics approval and consent to participate This study has been registered on the ClinicalTrials.gov registry website; Registration number: NCT06592898. This study was approved by the Clinical Trial Ethics Review Committee of Peking University Third Hospital. Competing interests The authors have no conflicts of interest to declare. References VAEGTER H B, LYNG K D, YTTERENG F W, et al. 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Clinical study of acupuncture and squatting training in the treatment of knee osteoarthritis [D]. Fujian University of Traditional Chinese Medicine, 2019. Chen Yiling. The clinical effect of static squatting training combined with acupuncture in the treatment of knee osteoarthritis [D]. Fujian University of Traditional Chinese Medicine, 2020. Wang Yu, Zheng Yi, Shi Qingzhao, et al. The surface EMG and patellofemoral joints of the quadriceps muscle are stressed at different angles Comparison of degrees of static squatting [J]. Science, Technology and Engineering, 2015,15 (03): 36-42. BESIER T F, DRAPER C E, GOLD G E, et al. Patellofemoral joint contact area increases with knee flexion and weight-bearing[J]. Journal of Orthopaedic Research, 2005,23(2): 345-350. BIEDERT R M, SANCHIS-ALFONSO V. Sources of anterior knee pain[J]. Clin Sports Med, 2002,21(3): 335-347. Wang Wenzhao, Zhang Yanlong, Song Chenglong, et al. Biomechanical analysis of lower limbs under different trunk forward leaning angles [J]. Contemporary Sports Technology, 2022,12 (09): 31-34. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6196818","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":428076275,"identity":"cb2947e0-106e-4f12-981c-642629957dbe","order_by":0,"name":"Hao-Ran Li","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Hao-Ran","middleName":"","lastName":"Li","suffix":""},{"id":428076276,"identity":"89c64dd0-9796-4380-8fc2-b6c7078864a3","order_by":1,"name":"Zi-Mu Fan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYBACNvbmww8/VNTwsDEzNj5IqKghrIWP51iascSZYzJ87M3NBg/OHCOsRU4iR0GCt43ZRo7neJvkwxZmIhzGc4bBQOIMGw+bRGJbRWIDGwN/e3cCAb/0HnhQUCED1nIjcYcMg8SZsxsI2HIuAW7LjcQzbEA7cwlokcgxAPkFrKUgsY2ZFC08B9sYiNMCDWQeNvbGZokEIIOgX+TbIVFpL9/M/vDjj4oaOf72XvxaMAAPacpHwSgYBaNgFGAFAB1WRlwzsiswAAAAAElFTkSuQmCC","orcid":"","institution":"","correspondingAuthor":true,"prefix":"","firstName":"Zi-Mu","middleName":"","lastName":"Fan","suffix":""},{"id":428076277,"identity":"8f5d5a18-a2a4-4337-8a3f-dea4bd4ae26b","order_by":2,"name":"Tao Huang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Tao","middleName":"","lastName":"Huang","suffix":""},{"id":428076278,"identity":"740c82c0-e310-4f9a-b79f-72214e71bf51","order_by":3,"name":"Yue-Yang Hou","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Yue-Yang","middleName":"","lastName":"Hou","suffix":""},{"id":428076279,"identity":"a4315d4d-fca3-4d7c-a664-18bd732a394e","order_by":4,"name":"Jian-Li Gao","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Jian-Li","middleName":"","lastName":"Gao","suffix":""},{"id":428076280,"identity":"3110324f-4b8d-4ec0-982c-d0d480c8cac5","order_by":5,"name":"Yan-Bing Zhang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Yan-Bing","middleName":"","lastName":"Zhang","suffix":""},{"id":428076281,"identity":"baa6f7fe-2e9f-4be6-bcc0-d25b917b6fc6","order_by":6,"name":"Zhi-Hui He","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Zhi-Hui","middleName":"","lastName":"He","suffix":""},{"id":428076282,"identity":"aa427cf6-c60f-433d-8447-4e76f942ec10","order_by":7,"name":"Yun-Fei Yuan","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Yun-Fei","middleName":"","lastName":"Yuan","suffix":""},{"id":428076283,"identity":"cf72d345-ce8a-417c-a416-85af57ad52e8","order_by":8,"name":"Zhen-Long Liu","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Zhen-Long","middleName":"","lastName":"Liu","suffix":""},{"id":428076284,"identity":"818cacda-2d0b-4edd-9483-8b27a818ea12","order_by":9,"name":"Shuang Ren","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Shuang","middleName":"","lastName":"Ren","suffix":""},{"id":428076285,"identity":"aa6cb2cd-b45d-48be-9640-0b99653e0f14","order_by":10,"name":"Hai-Yan Chang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Hai-Yan","middleName":"","lastName":"Chang","suffix":""},{"id":428076286,"identity":"0b09f73b-3496-453c-b4b3-b374d5d71982","order_by":11,"name":"Wei-Li Shi","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Wei-Li","middleName":"","lastName":"Shi","suffix":""},{"id":428076287,"identity":"9e2e1a88-909e-4195-9f66-da7f61fa9d76","order_by":12,"name":"Yu-Ping Yang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Yu-Ping","middleName":"","lastName":"Yang","suffix":""}],"badges":[],"createdAt":"2025-03-10 15:08:30","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6196818/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6196818/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":78920609,"identity":"6098fc49-453f-40c4-a007-242986284e66","added_by":"auto","created_at":"2025-03-20 20:37:58","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":249013,"visible":true,"origin":"","legend":"\u003cp\u003eParticipant undergoing an isokinetic strength test.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6196818/v1/522a65f361f0abaf98bacfe7.png"},{"id":78920611,"identity":"2ddaa5c5-9d5b-493a-8e86-8e67eafa9edc","added_by":"auto","created_at":"2025-03-20 20:37:58","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":234035,"visible":true,"origin":"","legend":"\u003cp\u003eParticipant assumes a supine position with straight leg lift.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6196818/v1/c66a2df94794e779505913f5.png"},{"id":78920034,"identity":"3259bf67-8e5c-4e7d-b928-00685207e57b","added_by":"auto","created_at":"2025-03-20 20:21:58","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":400773,"visible":true,"origin":"","legend":"\u003cp\u003eDemonstration of wall squat and practice guided by a mobile app.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6196818/v1/67e925e8651130cbde5dc740.png"},{"id":78920033,"identity":"6e460d97-6acb-4650-9b7b-b5decc5b4bdb","added_by":"auto","created_at":"2025-03-20 20:21:58","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":520488,"visible":true,"origin":"","legend":"\u003cp\u003eDemonstration of direct squat and practice guided by a mobile phone app.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6196818/v1/fa55e992c5409a4991f2048b.png"},{"id":78920040,"identity":"26afa9d5-37d4-4e90-9df1-a4a65f313800","added_by":"auto","created_at":"2025-03-20 20:21:58","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":275439,"visible":true,"origin":"","legend":"\u003cp\u003eDemonstration of wall squat assisted by elastic bands and practice guided by a mobile phone app.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-6196818/v1/fb883a208e8d26e1d62ce5f6.png"},{"id":80532551,"identity":"c1572297-0d4c-4fe1-bcff-7b29e2da99d5","added_by":"auto","created_at":"2025-04-14 11:17:13","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3373766,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6196818/v1/742659f9-36be-4ac5-b9db-5f4e98482ae7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Evaluation of different squatting modes in the rehabilitation of patellofemoral pain syndrome: A prospective randomized controlled trial","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eStatic squat is widely used in the treatment of various lower limb diseases. It can reduce pain and resting blood pressure [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], increase strength and volume of the deep abdominal muscles [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], and improve posture [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] and stability of the waist [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The commonly used modes of static squat in clinical practice are wall squat, direct squat, ball squat, and wall squat assisted by elastic bands. Each mode of static squat stimulates the quadriceps, hamstring, and multifidus muscles differently [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. However, the static squat mode that most effectively facilitates the rehabilitation of patients with patellofemoral pain syndrome (PFPS) remains to be studied.\u003c/p\u003e \u003cp\u003eThe force exerted on the patellofemoral joint (PFJ) is closely related to the angle of knee flexion, the distance between the heel and the wall, and the load-bearing capacity of one or both of the lower limbs. Among these factors, the distance between the heel and the wall is a particularly crucial determinant of the pressure on the PFJ [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The distance between the heel and the wall decreases while executing a wall squat, requiring the knee joint to bend a certain angle, which may result in the knee extending beyond the tips of the toes. For the same knee flexion angle, the pressure on the PFJ is higher during any movement wherein the knee extends beyond the toe tips compared with when it does not [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Moreover, the pressure on the PFJ is higher when squatting at the same angle with one leg compared with both the legs.\u003c/p\u003e \u003cp\u003eStudies on static squats have measured the degree of muscle activation in the lower limbs using surface electromyography [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Studies have indicated that static squats can not only stimulate the quadriceps and hamstring muscles but also the triceps, gluteus, abdominal, and multifidus muscles [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The quadriceps is the muscle group most closely related to PFPS. Ziyue Hu et al. discovered that the values of the surface electromyography parameters of the quadriceps continuously increased with knee flexion angle during static squatting. In the last stage of a static squat, when the vastus lateralis become fatigued, the discharge of the vastus medialis increases and the discharge of the rectus femoris subsequently increases, which suggests that training the vastus medialis and vastus lateralis first would be conducive to enhancing the strength of the quadriceps.\u003c/p\u003e \u003cp\u003eYu Wang et al. found by measuring the degree of muscle activation and patellofemoral joint force at different static squatting angles, when the angle set at 45\u0026deg;, comparing with 30\u0026deg;and 60\u0026deg;, quadriceps get tired more easily, the exercise is more effective. It is the appropriate angle for static squat exercise between 30\u0026deg;and 60\u0026deg;.(Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) Comparing with the research of Yu Wang and Ziyue Hu, it is found that the activation of muscle by squatting against the wall is more effective than direct squat.[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eQuadriceps iEMG at different static squatting angles (mV\u0026middot;s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAngle\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVastus lateralis\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRectus femoris\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVastus medialis\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e66.67\u0026thinsp;\u0026plusmn;\u0026thinsp;13.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e43.44\u0026thinsp;\u0026plusmn;\u0026thinsp;10.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e56.44\u0026thinsp;\u0026plusmn;\u0026thinsp;11.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e45\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e77.08\u0026thinsp;\u0026plusmn;\u0026thinsp;9.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e52.70\u0026thinsp;\u0026plusmn;\u0026thinsp;9.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e64.77\u0026thinsp;\u0026plusmn;\u0026thinsp;9.38\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e60\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e75.25\u0026thinsp;\u0026plusmn;\u0026thinsp;15.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e52.07\u0026thinsp;\u0026plusmn;\u0026thinsp;14.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e61.56\u0026thinsp;\u0026plusmn;\u0026thinsp;14.22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eNatelie Golding et al. adjusted wall squat intensity and explored the cardiovascular responses, they have found thatthe wall squat elicited similar cardiovascular responses to other isometric exercise modes that have reduced resting blood pressure, may have a useful role to play in isometric training aimed at reducing resting blood pressure.[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] The authors think that, compared with direct static squat, squat against the wall under the support of the wall is relatively easy to perform, which requires less stability of the human body, can reduce the resting blood pressure, and has less requirements for breathing and oxygen uptake. Therefore, squatting against the wall is a more appropriate training method. There\u0026rsquo;s no study verify that opinion.\u003c/p\u003e \u003cp\u003eMobile health\u0026mdash;the use of mobile apps to facilitate rehabilitation exercises at home\u0026mdash;is defined by the World Health Organization as the use of any mobile device, such as wearable monitoring devices, for obtaining medical or public health support [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. This study used a new remote rehabilitation movement recognition system, which can effectively determine the angle of knee flexion during static squatting. This measurement method was demonstrated to be accurate and first established in 2019 by Aditya et al., who used a simple mobile phone camera and an observation system based on the OpenPose algorithm without relying on peripheral equipment (e.g., wearable sensors and wristbands) to determine the angle of knee flexion and extension [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThis study explored the efficacy and therapeutic effects of three modes of static squats in patients with PFPS. The broader objective was to aid the application of mobile health to the home rehabilitation of patients with PFPS.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cp\u003eThis study is a prospective randomized controlled trial investigating the efficacy of different static squat modes in the rehabilitation of patients with PFPS. The study protocol was registered on the Protocol Registration and Results System (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://register.clinicaltrials.gov/\u003c/span\u003e\u003cspan address=\"https://register.clinicaltrials.gov/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e, identification number: NCT06592898 )\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Participants\u003c/h2\u003e \u003cp\u003eA random sample of 84 patients were screened from among all patients in Peking University Third Hospital and Chongli Branch from January 2023 to September 2023. The recruited patients were randomly assigned to either the experimental groups or the control group, with 21 participants per group. This study was approved by the Ethics Committee of Peking University Third Hospital (M2023013). All the participants provided their written informed consent.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Inclusion criteria\u003c/h2\u003e \u003cp\u003eIndividuals were included in this study if (1) they met the diagnostic criteria of PFPS; (2) they were aged 20\u0026ndash;45 years old, to reduce the risk of osteoarthritis affecting the PFJ [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]; (3) they were not on any treatment regimen before the experiment; and (4) they had provided signed informed consent.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Exclusion criteria\u003c/h2\u003e \u003cp\u003eIndividuals were excluded from this study if (1) they had already had surgery; (2) they had other lower limb injuries, such as meniscus tear, bursitis, ligament injury, patellar tendon injury, or joint degeneration; (3) they had a history of patellofemoral dislocation and subluxation; (4) they had cardiovascular or cerebrovascular diseases, lung disease, kidney disease, or other prominent visceral diseases; (5) they were cognitively impaired and unable to use mobile apps.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Instrument\u003c/h2\u003e \u003cp\u003eThe participants were assessed by the same researcher using the Biodex isokinetic muscle strength tester (Biodex, New York, USA) at baseline and 6 weeks after the intervention (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Both knee joints of the participants were assessed, and the isokinetic muscle force test was performed at an angular velocity of 60\u0026deg; per second. Participants who reported pain in both their PFJs were subjected to indicator analysis. Pain is most severe at the peak moment of knee flexion and extension of the lower limb. Data on each indicator were collected, recorded into Microsoft Excel, and summarized. After all participants underwent the intervention, the data in Excel were transferred into SPSS 26 software (IBM, New York, USA) for processing and analysis.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe measurement data were subjected to normality and homogeneity of variance tests prior to statistical analysis. Results for variables with homogenous variance and a normal distribution are presented as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. The participants\u0026rsquo; Kujala scores, Lysholm scores, Visual Analog Scale for Worst pain (VAS-W) scores, and Visual Analog Scale for Usual pain (VAS-U) scores were analyzed using two-factor analysis of variance.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Research methods\u003c/h2\u003e \u003cp\u003eThe 84 participants with PFPS were numbered according to the order of treatment. A randomized controlled trial was designed, comprising a control group and three experimental groups corresponding to three static squat modes. Movement quality was monitored using a mobile app (Yiyuetsu Technology, Beijing, China). The random number generator in SPSS 26.0 software was used to assign participants to one of the four groups, with 21 participants per group. VAS, scores on the anterior knee pain scale and Lysholm knee score scale, thigh circumference, and peak torque of knee extension were compared preintervention and postintervention to determine the optimal static squat mode.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Intervention methods for the control group\u003c/h2\u003e \u003cp\u003eThe participants in the control group assumed a supine position with straight leg lift (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The other knee (of the leg that was not lifted) was at 90\u0026deg;, with the foot placed flat on the ground. The ankle was flexed to contract the quadriceps on the other side. The knee joint was then straightened, and the thigh was lifted for the hip to be at 30\u0026deg;. The heel was approximately 20 cm away from the ground. Finally, the leg was lowered to a resting position after 2 s. Ten repetitions of this action constituted a group. Each practice session had five groups, with a 1-minute rest between groups. Practice sessions were held five times a week and involved both legs. The participants were asked to breathe normally throughout without holding their breath.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e2.7 Intervention methods for the experimental groups\u003c/h2\u003e \u003cp\u003eThe three experimental groups corresponded to three modes of static squats: wall squat (group A), direct squat (group B), and wall squat assisted by elastic bands (group C).\u003c/p\u003e \u003cp\u003eIn group A, the participants\u0026rsquo; upper body was upright, the distance between their feet was equivalent to the width of their shoulders, and their hands were placed on either side of the body or above the thighs. Their toe tips were toward the front and perpendicular to the wall. The distance between the wall and their heels was approximately a foot, their back was close to the wall, and the squat was performed slowly (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe angle of the wall squat ranged from 30\u0026deg; to 60\u0026deg;. The pressure on the PFJ is too high at angles exceeding 60\u0026deg;. Moreover, training at a large angle for a long time may lead to secondary injury of the knee joint [\u003cspan additionalcitationids=\"CR17 CR18\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The angle was set at 30\u0026deg; for the first 2 weeks, after which it was increased to 45\u0026deg; and finally set at 60\u0026deg; for the last 2 weeks.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn group B, the participants stood on the flat ground with their upper body upright, the distance between their feet was equivalent to the width of their shoulders, and their toe tips were toward the front. Their trunk was adjusted forward according to the angle of static squat. The specific method included aligning the trunk with the shoulder joint and knee joint perpendicular to the ground. The knee joint can bend to a large angle [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The participants were asked to put their hands in front of their bodies, and their center of gravity was between their feet. The angle was set at 30\u0026deg; for the first 2 weeks, after which it was increased to 45\u0026deg; and finally set at 60\u0026deg; for the last 2 weeks. (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eIn group C, the participants performed wall squats but with an elastic band of 20 pounds wrapped around their thighs. They opened their thighs and feet at a low speed, so that the elastic bands were slightly deformed and they experienced an obvious resistance on the outside of their thighs. The angle was set at 30\u0026deg; for the first 2 weeks, after which it was increased to 45\u0026deg; and finally set at 60\u0026deg; for the last 2 weeks (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe duration of each squat mode was until the participants could no longer squat, and the exhaustion of muscle endurance marked the end point of the exercise. The rest time between practice sessions was 1 minute. The participants were required to squat five times a day for five days a week. The total study duration was 6 weeks, and the participants were followed up during the third week and sixth weeks. The subjective indicators were followed up by filling out the rating scale offline before intervention and during the third and sixth weeks of the intervention, so that the researchers could better explain the follow-up contents to the participants. The participants\u0026rsquo; objective indicators were assessed before the intervention and after 6 weeks of the intervention.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e2.8 Quality and compliance control\u003c/h2\u003e \u003cp\u003eThe angle of static squat was determined using an artificial intelligence system on a mobile app and was used to indicate the quality of the participants\u0026rsquo; static squat. The app sent training reminders to the participants at 1 pm and 8 pm every day. The researchers monitored the participants\u0026rsquo; training status and duration on the app at 10 pm every day to stay up-to-date about the participants\u0026rsquo; home rehabilitation progress. The researchers contacted participants who did not engage in training on WeChat or by telephone to encourage them to participate in training.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003e \u003cem\u003e3.1 General data on the participants\u003c/em\u003e A total of 84 participants were recruited in this study, divided into four groups by single-blind randomization (21 participants per group; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Kujala score\u003c/h2\u003e \u003cp\u003eThe Kujala scores of the control group were 71.67\u0026thinsp;\u0026plusmn;\u0026thinsp;5.78, 73.24\u0026thinsp;\u0026plusmn;\u0026thinsp;4.95, and 74.86\u0026thinsp;\u0026plusmn;\u0026thinsp;4.87 at baseline, at 3 weeks, and at 6 weeks from the start of training, respectively. For these three time points, the Kujala scores of group A were 71.70\u0026thinsp;\u0026plusmn;\u0026thinsp;8.73, 78.30\u0026thinsp;\u0026plusmn;\u0026thinsp;6.61, and 85.95\u0026thinsp;\u0026plusmn;\u0026thinsp;4.33, respectively; those of group B were 72.30\u0026thinsp;\u0026plusmn;\u0026thinsp;5.44, 73.35\u0026thinsp;\u0026plusmn;\u0026thinsp;5.53, and 73.15\u0026thinsp;\u0026plusmn;\u0026thinsp;4.92, respectively; and of group C were 74.19\u0026thinsp;\u0026plusmn;\u0026thinsp;6.76, 79.43\u0026thinsp;\u0026plusmn;\u0026thinsp;6.23, and 82.86\u0026thinsp;\u0026plusmn;\u0026thinsp;4.87, respectively.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCharacteristics of the study sample\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eControl Group\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup A\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGroup B\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGroup C\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGender\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.84\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.05\u0026thinsp;\u0026plusmn;\u0026thinsp;5.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e37.30\u0026thinsp;\u0026plusmn;\u0026thinsp;8.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33.20\u0026thinsp;\u0026plusmn;\u0026thinsp;7.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e34.43\u0026thinsp;\u0026plusmn;\u0026thinsp;7.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.24\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeight (cm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e170.00\u0026thinsp;\u0026plusmn;\u0026thinsp;7.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e170.70\u0026thinsp;\u0026plusmn;\u0026thinsp;8.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e169.90\u0026thinsp;\u0026plusmn;\u0026thinsp;7.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e169.81\u0026thinsp;\u0026plusmn;\u0026thinsp;8.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeight (kg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e65.14\u0026thinsp;\u0026plusmn;\u0026thinsp;11.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e66.75\u0026thinsp;\u0026plusmn;\u0026thinsp;13.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e63.45\u0026thinsp;\u0026plusmn;\u0026thinsp;10.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e65.48\u0026thinsp;\u0026plusmn;\u0026thinsp;9.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.84\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCondition\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.96\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBoth\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeft\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003csup\u003ea\u003c/sup\u003e Data on gender and condition of participants are presented in terms of frequency (number of people). Data on age, height, and weight are presented in terms of the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Lysholm scores\u003c/h2\u003e \u003cp\u003eThe Lysholm scores of the control group were 74.95\u0026thinsp;\u0026plusmn;\u0026thinsp;6.20, 74.90\u0026thinsp;\u0026plusmn;\u0026thinsp;6.32, and 75.71\u0026thinsp;\u0026plusmn;\u0026thinsp;6.03 at baseline, at 3 weeks, and at 6 weeks from the start of training, respectively. For these three time points, the Lysholm scores of group A were 73.20\u0026thinsp;\u0026plusmn;\u0026thinsp;4.61, 73.60\u0026thinsp;\u0026plusmn;\u0026thinsp;6.00, and 77.20\u0026thinsp;\u0026plusmn;\u0026thinsp;5.25, respectively; those of group B were 74.60\u0026thinsp;\u0026plusmn;\u0026thinsp;4.58, 75.10\u0026thinsp;\u0026plusmn;\u0026thinsp;3.91, and 78.45\u0026thinsp;\u0026plusmn;\u0026thinsp;5.01, respectively; and those of group C were 75.43\u0026thinsp;\u0026plusmn;\u0026thinsp;5.30, 75.71\u0026thinsp;\u0026plusmn;\u0026thinsp;6.19, and 82.52\u0026thinsp;\u0026plusmn;\u0026thinsp;7.37, respectively.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.4 VAS-W scores\u003c/h2\u003e \u003cp\u003eThe VAS-W scores of the control group were 6.00 \u0026plusmn;\u003c/p\u003e \u003cp\u003e1.05, 4.52\u0026thinsp;\u0026plusmn;\u0026thinsp;1.44, and 3.52\u0026thinsp;\u0026plusmn;\u0026thinsp;1.60 at baseline, at 3 weeks, and at 6 weeks from the start of training, respectively. For these three time points, the VAS-W scores of group A were 5.25\u0026thinsp;\u0026plusmn;\u0026thinsp;1.37, 3.80\u0026thinsp;\u0026plusmn;\u0026thinsp;1.06, and 2.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27, respectively; those of group B were 5.30\u0026thinsp;\u0026plusmn;\u0026thinsp;1.38, 5.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.97, and 4.80\u0026thinsp;\u0026plusmn;\u0026thinsp;1.01, respectively; and those of group C were 5.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.06, 3.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.06, and 1.43\u0026thinsp;\u0026plusmn;\u0026thinsp;1.16, respectively.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.5 VAS-U scores\u003c/h2\u003e \u003cp\u003eThe VAS-U scores of the control group were 4.10\u0026thinsp;\u0026plusmn;\u0026thinsp;1.00, 3.81\u0026thinsp;\u0026plusmn;\u0026thinsp;1.17, and 3.76\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94 at baseline, at 3 weeks, and at 6 weeks from the start of training, respectively. For these time points, the VAS-U scores of group A were 3.40\u0026thinsp;\u0026plusmn;\u0026thinsp;1.05, 3.20\u0026thinsp;\u0026plusmn;\u0026thinsp;1.20, and 2.25\u0026thinsp;\u0026plusmn;\u0026thinsp;1.25, respectively; those of group B were 3.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27, 3.30\u0026thinsp;\u0026plusmn;\u0026thinsp;1.34, and 3.30\u0026thinsp;\u0026plusmn;\u0026thinsp;1.38, respectively; and those of group C were 3.57\u0026thinsp;\u0026plusmn;\u0026thinsp;1.33, 2.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.24, and 1.52\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12, respectively.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.6 Thigh circumference\u003c/h2\u003e \u003cp\u003eThe thigh circumferences of the control group before and after training were 46.09\u0026thinsp;\u0026plusmn;\u0026thinsp;3.93 and 46.55\u0026thinsp;\u0026plusmn;\u0026thinsp;3.71, respectively. For these two time points, the thigh circumferences of group A were 45.92\u0026thinsp;\u0026plusmn;\u0026thinsp;2.97 and 47.02\u0026thinsp;\u0026plusmn;\u0026thinsp;3.14, respectively, those of group B were 46.08\u0026thinsp;\u0026plusmn;\u0026thinsp;2.52 and 47.03\u0026thinsp;\u0026plusmn;\u0026thinsp;2.17, respectively, and of group C were 46.74\u0026thinsp;\u0026plusmn;\u0026thinsp;3.82 and 48.82\u0026thinsp;\u0026plusmn;\u0026thinsp;3.53, respectively.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e3.7 Peak knee torque in isokinetic muscle strength test\u003c/h2\u003e \u003cp\u003eThe peak knee torques in the control group before and after training were 78.25\u0026thinsp;\u0026plusmn;\u0026thinsp;21.34 and 83.65\u0026thinsp;\u0026plusmn;\u0026thinsp;16.38, respectively. For these two time points, the peak knee torques in group A were 74.89\u0026thinsp;\u0026plusmn;\u0026thinsp;32.88 and 98.36\u0026thinsp;\u0026plusmn;\u0026thinsp;33.84, respectively, those in group B were 76.64\u0026thinsp;\u0026plusmn;\u0026thinsp;18.60 and 85.77\u0026thinsp;\u0026plusmn;\u0026thinsp;19.64, respectively, and those in group C were 75.31\u0026thinsp;\u0026plusmn;\u0026thinsp;19.57 and 101.8\u0026thinsp;\u0026plusmn;\u0026thinsp;14.40, respectively.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePreintervention and postintervention results for comparison\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eControl Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup A\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGroup B\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGroup C\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKujala score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ebefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e71.67\u0026thinsp;\u0026plusmn;\u0026thinsp;5.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e71.70\u0026thinsp;\u0026plusmn;\u0026thinsp;8.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e72.30\u0026thinsp;\u0026plusmn;\u0026thinsp;5.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e74.19\u0026thinsp;\u0026plusmn;\u0026thinsp;6.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.59\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e73.24\u0026thinsp;\u0026plusmn;\u0026thinsp;4.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e78.30\u0026thinsp;\u0026plusmn;\u0026thinsp;6.61\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e73.35\u0026thinsp;\u0026plusmn;\u0026thinsp;5.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e79.43\u0026thinsp;\u0026plusmn;\u0026thinsp;6.23\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e74.86\u0026thinsp;\u0026plusmn;\u0026thinsp;4.87\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e85.95\u0026thinsp;\u0026plusmn;\u0026thinsp;4.33\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e73.15\u0026thinsp;\u0026plusmn;\u0026thinsp;4.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e82.86\u0026thinsp;\u0026plusmn;\u0026thinsp;4.87\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLysholm score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ebefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e74.95\u0026thinsp;\u0026plusmn;\u0026thinsp;6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e73.20\u0026thinsp;\u0026plusmn;\u0026thinsp;4.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e74.60\u0026thinsp;\u0026plusmn;\u0026thinsp;4.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e75.43\u0026thinsp;\u0026plusmn;\u0026thinsp;5.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.56\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e74.90\u0026thinsp;\u0026plusmn;\u0026thinsp;6.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e73.60\u0026thinsp;\u0026plusmn;\u0026thinsp;6.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e75.10\u0026thinsp;\u0026plusmn;\u0026thinsp;3.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e75.71\u0026thinsp;\u0026plusmn;\u0026thinsp;6.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.69\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75.71\u0026thinsp;\u0026plusmn;\u0026thinsp;6.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e77.20\u0026thinsp;\u0026plusmn;\u0026thinsp;5.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e78.45\u0026thinsp;\u0026plusmn;\u0026thinsp;5.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e82.52\u0026thinsp;\u0026plusmn;\u0026thinsp;7.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVAS-W score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ebefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.00\u0026thinsp;\u0026plusmn;\u0026thinsp;1.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.25\u0026thinsp;\u0026plusmn;\u0026thinsp;1.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.30\u0026thinsp;\u0026plusmn;\u0026thinsp;1.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.52\u0026thinsp;\u0026plusmn;\u0026thinsp;1.44\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.80\u0026thinsp;\u0026plusmn;\u0026thinsp;1.06\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.29\u0026thinsp;\u0026plusmn;\u0026thinsp;1.06\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.52\u0026thinsp;\u0026plusmn;\u0026thinsp;1.60\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.80\u0026thinsp;\u0026plusmn;\u0026thinsp;1.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.43\u0026thinsp;\u0026plusmn;\u0026thinsp;1.16\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVAS-U score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ebefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.10\u0026thinsp;\u0026plusmn;\u0026thinsp;1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.40\u0026thinsp;\u0026plusmn;\u0026thinsp;1.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.57\u0026thinsp;\u0026plusmn;\u0026thinsp;1.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.26\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.81\u0026thinsp;\u0026plusmn;\u0026thinsp;1.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.20\u0026thinsp;\u0026plusmn;\u0026thinsp;1.20\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.30\u0026thinsp;\u0026plusmn;\u0026thinsp;1.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.24\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.76\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.25\u0026thinsp;\u0026plusmn;\u0026thinsp;1.25\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.30\u0026thinsp;\u0026plusmn;\u0026thinsp;1.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.52\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThighs circumference\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ebefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46.09\u0026thinsp;\u0026plusmn;\u0026thinsp;3.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e45.92\u0026thinsp;\u0026plusmn;\u0026thinsp;2.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e46.08\u0026thinsp;\u0026plusmn;\u0026thinsp;2.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e46.75\u0026thinsp;\u0026plusmn;\u0026thinsp;3.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.86\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46.55\u0026thinsp;\u0026plusmn;\u0026thinsp;3.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e47.01\u0026thinsp;\u0026plusmn;\u0026thinsp;3.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e47.03\u0026thinsp;\u0026plusmn;\u0026thinsp;2.17\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e48.82\u0026thinsp;\u0026plusmn;\u0026thinsp;3.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePeak torque of knee extension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ebefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e78.25\u0026thinsp;\u0026plusmn;\u0026thinsp;21.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e74.89\u0026thinsp;\u0026plusmn;\u0026thinsp;32.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e75.63\u0026thinsp;\u0026plusmn;\u0026thinsp;18.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e75.31\u0026thinsp;\u0026plusmn;\u0026thinsp;19.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.97\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e83.65\u0026thinsp;\u0026plusmn;\u0026thinsp;16.38\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e98.36\u0026thinsp;\u0026plusmn;\u0026thinsp;33.84\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e85.77\u0026thinsp;\u0026plusmn;\u0026thinsp;19.64\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e101.85\u0026thinsp;\u0026plusmn;\u0026thinsp;14.40\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePeak torque of knee flexion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ebefore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e37.38\u0026thinsp;\u0026plusmn;\u0026thinsp;11.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e38.26\u0026thinsp;\u0026plusmn;\u0026thinsp;19.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e38.55\u0026thinsp;\u0026plusmn;\u0026thinsp;12.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e37.23\u0026thinsp;\u0026plusmn;\u0026thinsp;9.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 weeks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e37.81\u0026thinsp;\u0026plusmn;\u0026thinsp;12.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e42.36\u0026thinsp;\u0026plusmn;\u0026thinsp;21.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e54.50\u0026thinsp;\u0026plusmn;\u0026thinsp;10.86\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e45.49\u0026thinsp;\u0026plusmn;\u0026thinsp;10.83\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003csup\u003ea\u003c/sup\u003e Data are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation\u003c/p\u003e \u003cp\u003e \u003csup\u003eb\u003c/sup\u003e For thigh circumference score and peak torque of knee extension/flexion, a\u003cem\u003eP\u003c/em\u003e denotes a comparison in the group with the corresponding values before intervention, a\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/p\u003e \u003cp\u003e \u003csup\u003ec\u003c/sup\u003e For Kujala, VAS-W, and VAS-U scores, a\u003cem\u003eP\u003c/em\u003e denotes a comparison with the corresponding values before intervention, a\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05, and b\u003cem\u003eP\u003c/em\u003e denotes a comparison with the corresponding values at 3 weeks, b\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e3.8 Peak knee moment in isokinetic muscle strength test\u003c/h2\u003e \u003cp\u003eThe peak knee moments in the control group before and after training were 37.38\u0026thinsp;\u0026plusmn;\u0026thinsp;11.90 and 37.81\u0026thinsp;\u0026plusmn;\u0026thinsp;12.21, respectively. For these two time points, the peak knee moments in group A were 38.26\u0026thinsp;\u0026plusmn;\u0026thinsp;19.37 and 42.36\u0026thinsp;\u0026plusmn;\u0026thinsp;21.03, respectively; those in group B were 38.55\u0026thinsp;\u0026plusmn;\u0026thinsp;12.81 and 54.50\u0026thinsp;\u0026plusmn;\u0026thinsp;10.86, respectively; and those in group C were 37.23\u0026thinsp;\u0026plusmn;\u0026thinsp;9.32 and 45.49 \u0026plusmn; 10.83, respectively.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis prospective randomized controlled trial demonstrated that all three static squat modes effectively alleviated pain and improved PFJ function but to different extents.\u003c/p\u003e \u003cp\u003eThe central difference between a direct squat and a wall squat is in the pressure exerted on the PFJ. Wall squats can be divided into long versus short squats against the wall, according to the relative position of the knee joint and the toe. The knee joint is behind and in front of the toe tips in long and short squats against the wall, respectively. This study used the long squat against the wall. During direct squats, the knee joint easily exceeds the toe tips due to the center of gravity. The extension of the knee beyond the toe exerts high pressure on the PFJ, which may lead to the development of PFPS. The excessive pressure directly acts on the synovial fold, subpatellofemoral fat pad, support band, joint capsule, patellofemoral ligament, and subchondral bone [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Subchondral bone plates are filled with pain receptors; thus, increased subchondral bone stress caused by high patellofemoral pressure may also lead to PFPS [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWen-Zhao Wang et al. investigated the Taichi horse stance and noted that this stance could be assumed using the normal trunk pattern (NTP) and the anteverted trunk pattern (ATP). The maximum range of hip joint flexion and extension under NTP is smaller than that under ATP. When the torso is kept straight, the pelvis rotates forward around the coronal axis, and the hip joint has a greater flexion amplitude when the human individual\u0026rsquo;s lower limb is in a closed chain stance. Studies have also indicated that the contact area between the femoral patellae increases with knee flexion angle, which helps distribute the pressure on the patella over a larger area, thereby mitigating contact stress and alleviating pain in patients with femoral patellae pain syndrome. The maximum knee angle under NTP was significantly smaller than that under ATP (i.e., the knee motion amplitude of the NTP was significantly larger than that of the ATP).\u003c/p\u003e \u003cp\u003eIn the aforementioned study of Wen-Zhao Wang et al., the individual assuming the NTP tried to maintain the position of the knee joint within the position of the toe, implying that the difference between NTP and wall squat may only lie in whether squatting against a wall dispersed the force on the knee joint during squatting, thereby relieving pain associated with PFPS. In addition, the direct squat used in this study was the same as ATP. The maximum knee angle of the NTP group was significantly smaller than that of the ATP group, thus reducing the contact stress of the knee joint to alleviate pain in patients with PFPS. Squatting against the wall seems to generate less pressure on the PFJ than squatting directly, which is more conducive to the rehabilitation treatment of patients with PFPS. The results of the present study also indicate that the final knee function score of the participants in the direct static squat group was worse than that of participants in the other groups, which may be related to the excessive pressure exerted on the PFJ [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Limitations and future directions\u003c/h2\u003e \u003cp\u003eThis study only focused on the clinical manifestations of patients with PFPS during static squatting training; it neither explored the contraction of muscles in each part of the lower extremities during the three static squatting modes nor evaluated the specific load exerted on the PFJ. Moreover, the duration of follow-up in this study was short, and no follow-up data were collected on whether the participants continued their training, whether pain recurred, or whether they resumed exercise. In addition, the intervention duration of this study was short, which precluded the possibility of determining the long-term efficacies of the three static squat modes in the rehabilitation of patients with PFPS. Future studies should explore the therapeutic differences between the different static squat modes from the perspectives of longer intervention and follow-up durations and the specific activation of lower limb and trunk muscles during static squat.\u003c/p\u003e \u003cp\u003eFurthermore, the dose-response relationship of many traditional Chinese sports such as Tai chi and Taichi horse stance has not been studied systematically as aerobic exercise and resistance training, many important questions have not been answered. Such as how many hours should Tai Chi be practiced each time, and how many times a week? How many years can practicing Tai Chi add to your life? How much disease risk can be reduced? What is the mechanism of Tai Chi? What's the difference from cardio and strength training?\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThis study aids the use of mobile health in the home rehabilitation of patients with PFPS. Patients with PFPS can train by performing wall squats or wall squats assisted by elastic bands, which can effectively improve PFJ function and reduce pain. Wall squat with elastic bands is the better choice of the two because it effectively stimulates the vastus medialis and vastus lateralis to alleviate pain. When patients with PFPS do not have any instruments accessible, they can train by performing wall squats. Direct squats are not a suitable exercise for patients with early PFPS; although direct squats can enhance muscle strength around the knee joint, they have limited benefits in improving PFJ function or alleviating PFJ pain.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePFPS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003epatellofemoral pain syndrome\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePFJ\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003epatellofemoral joint\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eAKPS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eanterior knee pain scale\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eLKSS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003elysholm knee score scale\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eVAS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003evisual analogue scale\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eNTP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003enormal trunk pattern\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eATP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eanteverted trunk pattern.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHao-Ran Li and Zi-Mu Fan are the primary designers of research. All authors have made suggestions for the research design and will be involved in the execution of the research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSupported by the National Natural Science Foundation of China for mechanism of hydrogel with RP1 inhibitor in treatment of \u003cem\u003edegenerative tendinopathy (82372449)\u0026nbsp;\u003c/em\u003eand the Key Special Project of Peking University Third Hospital for comparing the clinical efficacy of Arthroscopic Lateral Retinacular Release and exercise therapy in the treatment of Lateral Patellar Compression Syndrome (BYSYDL2023013).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used or analyzed during the current study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study has been registered on the ClinicalTrials.gov registry website; Registration number: NCT06592898. This study was approved\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eby the Clinical Trial Ethics Review Committee of Peking University Third Hospital.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no conflicts of interest to declare.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eVAEGTER H B, LYNG K D, YTTERENG F W, et al. Exercise-Induced Hypoalgesia After Isometric Wall Squat Exercise: A Test-Retest Reliabilty Study[J]. Pain Medicine, 2019,20(1): 129-137.CHO M.\u003c/li\u003e\n\u003cli\u003eThe effects of modified wall squat exercises on average adults\u0026apos; deep abdominal muscle thickness and lumbar stability[J]. J Phys Ther Sci, 2013,25(6): 689-692.\u003c/li\u003e\n\u003cli\u003eLEE Y. The influence of unstable modified wall squat exercises on the posture of female university students[J]. J Phys Ther Sci, 2015,27(8): 2477-2480.\u003c/li\u003e\n\u003cli\u003eCHO M. The effects of modified wall squat exercises on average adults\u0026apos; deep abdominal muscle thickness and lumbar stability[J]. J Phys Ther Sci, 2013,25(6): 689-692.\u003c/li\u003e\n\u003cli\u003eGOLDRING N, WILES J D, COLEMAN D. The effects of isometric wall squat exercise on heart rate and blood pressure in a normotensive population[J]. J Sports Sci, 2014,32(2): 129-136.\u003c/li\u003e\n\u003cli\u003eLiu Dandan, Chen Lianghua, Chen Jingjie, et al. Effect of different squatting states on surface EMG signals in leg muscles and lumbar multifidus [J]. Journal of Practical Medicine, 2017,33 (24): 4069-4073.\u003c/li\u003e\n\u003cli\u003eESCAMILLA R F, ZHENG N, MACLEOD T D, et al. Patellofemoral joint force and stress during the wall squat and one-leg squat[J]. Med Sci Sports Exerc, 2009,41(4): 879-888.\u003c/li\u003e\n\u003cli\u003eCROSSLEY K M, COWAN S M, BENNELL K L, et al. Knee flexion during stair ambulation isaltered in individuals with patellofemoral pain[J]. Journal of Orthopaedic Research, 2004,22(2):267-274.\u003c/li\u003e\n\u003cli\u003eLuo Jiong and Jin Jichun. Treatment method of surface EMG and its application prospect in sports scientific research [J]. Journal of Shandong Institute of Physical Education, 2005 (02): 56-59.\u003c/li\u003e\n\u003cli\u003eMACADAM P, FESER E H. Examination of gluteus maximus electromyographic excitation associated with dynamic hip extension during body weight exercise: a systematic review[J]. Int J Sports Phys Ther, 2019,14(1): 14-31.\u003c/li\u003e\n\u003cli\u003eWang Yu, Zheng Yi, Shi Qingzhao, et al. Comparison of quadriceps surface electromyography and patellofemoral joint forces at different angles [J]. Science, Technology and Engineering, 2015,15 (03): 36-42.\u003c/li\u003e\n\u003cli\u003eGoldring, N., Wiles, J. D., \u0026amp; Coleman, D. (2013). The effects of isometric wall squat exercise on heart rate and blood pressure in a normotensive population. \u003cem\u003eJournal of Sports Sciences\u003c/em\u003e, \u003cem\u003e32\u003c/em\u003e(2), 129\u0026ndash;136. https://doi.org/10.1080/02640414.2013.809471\u003c/li\u003e\n\u003cli\u003eLi Miao. Focus on mobile health: Opportunities and Challenges are coming [J]. Strategic Emerging Industries in China, 2015 (24): 29-32.\u003c/li\u003e\n\u003cli\u003eVISWAKUMAR A, RAJAGOPALAN V, RAY T, et al. Human Gait Analysis Using OpenPose: IEEE, 2019.\u003c/li\u003e\n\u003cli\u003eDEMIRCI S, KINIKLI G I, CALLAGHAN M J, et al. Comparison of short-term effects of mobilization with movement and Kinesiotaping on pain, function and balance in patellofemoral pain[J]. Acta Orthop Traumatol Turc, 2017,51(6): 442-447.\u003c/li\u003e\n\u003cli\u003eLiu Yiliang. Comparative study on the efficacy of knee atella compared versus wall squatting [D]. China University of Geosciences (Beijing), 2021.\u003c/li\u003e\n\u003cli\u003eGong Chunbo. Clinical study of acupuncture and squatting training in the treatment of knee osteoarthritis [D]. Fujian University of Traditional Chinese Medicine, 2019.\u003c/li\u003e\n\u003cli\u003eChen Yiling. The clinical effect of static squatting training combined with acupuncture in the treatment of knee osteoarthritis [D]. Fujian University of Traditional Chinese Medicine, 2020.\u003c/li\u003e\n\u003cli\u003eWang Yu, Zheng Yi, Shi Qingzhao, et al. The surface EMG and patellofemoral joints of the quadriceps muscle are stressed at different angles Comparison of degrees of static squatting [J]. Science, Technology and Engineering, 2015,15 (03): 36-42.\u003c/li\u003e\n\u003cli\u003eBESIER T F, DRAPER C E, GOLD G E, et al. Patellofemoral joint contact area increases with knee flexion and weight-bearing[J]. Journal of Orthopaedic Research, 2005,23(2): 345-350.\u003c/li\u003e\n\u003cli\u003eBIEDERT R M, SANCHIS-ALFONSO V. Sources of anterior knee pain[J]. Clin Sports Med, 2002,21(3): 335-347.\u003c/li\u003e\n\u003cli\u003eWang Wenzhao, Zhang Yanlong, Song Chenglong, et al. Biomechanical analysis of lower limbs under different trunk forward leaning angles [J]. Contemporary Sports Technology, 2022,12 (09): 31-34.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Patellofemoral pain syndrome, Static squat, Rehabilitation","lastPublishedDoi":"10.21203/rs.3.rs-6196818/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6196818/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cem\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e: \u003c/strong\u003eStatic squats are widely used in the treatment of patellofemoral pain syndrome (PFPS), but no study has determined the most effective static squat mode. This study compared the efficacies of three static squat modes in the rehabilitation of patients with PFPS.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e: \u003c/strong\u003eThis studyrecruited 84 patients with PFPS who were divided into four groups on the basis of different static squat modes. The patients underwent a 6-week training period using a mobile phone app equipped with angle recognition function. Treatment efficacy was assessed using the Kujala, Lysholm, VAS-W, and VAS-U scores, as well as the thigh circumference, peak torque of knee extension, and peak torque of knee flexion on the affected side. Intra- and intergroup differences were analyzed using two-way analysis of variance. Moreover, a paired-sample t-test and one-way analysis of variance were applied for intergroup comparisons. Chi-square tests were performed on categorical data.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e: \u003c/strong\u003eWall squats assisted by elastic bandssignificantly differed from the control in terms of the Kujala, Lysholm, VAS-W, and VAS-U scores (P \u0026lt; 0.05). Thigh circumference and peak torque of knee extension in isokinetic muscle strength tests were normally distributed and had homogeneous variance.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e: \u003c/strong\u003eWall squats can effectively improve patellofemoral joint function and alleviate pain. This study aids the home rehabilitation of patients with PFPS.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRegistration number: \u003c/strong\u003eM2023013\u003c/p\u003e","manuscriptTitle":"Evaluation of different squatting modes in the rehabilitation of patellofemoral pain syndrome: A prospective randomized controlled trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-20 20:21:53","doi":"10.21203/rs.3.rs-6196818/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6c21896d-e532-40e3-a1cd-3588c3420f40","owner":[],"postedDate":"March 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-04-14T11:08:51+00:00","versionOfRecord":[],"versionCreatedAt":"2025-03-20 20:21:53","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6196818","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6196818","identity":"rs-6196818","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}