The Effect of Long Interval Training on Swimming Performance and Stroke Kinematics in Adolescent Swimmers

The Effect of Long Interval Training on Swimming Performance and Stroke Kinematics in Adolescent Swimmers | 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 Article The Effect of Long Interval Training on Swimming Performance and Stroke Kinematics in Adolescent Swimmers Esila Durğut Yalın, Erdem Uylas, Erkan Günay This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6750664/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 This study aimed to investigate the effects of 6-week long interval training (LIT) program on 100 meter (m) freestyle, graded swimming performance and stroke biomechanics. Nine swimmers (13.55 ± 1.42 years) were included the LIT. This training period consisted of 4x300 m swims 3 times a week. Graded Swimming Protocol (GSP) and 100 m freestyle swimming performance were performed before and after the LIT period to evaluate the stroke kinematic and swimming performance changes. The paired sample-t test analysis determined in all parameters before and after the test. The result of GSP showed improvements in swimming velocity (p = 0.001), stroke length (p = 0.011), stroke index (p = 0.001), index of coordination (p = 0.013). Stroke rate (SR) values demonstrated decrease in certain stages and increase in others. In the 100 m test, the swimming speed (p = 0.010), stroke length (SL) (p = 0.028), stroke index (SI) (p = 0.006) improved. There was a slightly decrease in SR, but not significant. This training method in adolescent swimmers can be used as a unique method for improving stroke kinematic parameters that support aerobic capacity-based swimming performance enhancement. Biological sciences/Physiology Health sciences/Anatomy Adolescent Swimmers Interval Training 100 Meter Freestyle Swimming Performance Graded Swimming Protocol Stroke Kinematics Figures Figure 1 Figure 2 Introduction Optimal swimming performance requires determining different age groups physiological and physical needs. For arrival, the optimal performance depends on steady progression and the use of corresponding training methods. Age-related physiological changes in adolescent swimmers should be considered to achieve optimal performance in all these training methods ( 1 ). These training methods improve the efficiency of recovery by increasing muscle strength and endurance ( 2 ). For the development of these physiological processes, swimming-specific technical parameters should be included in training programs. Technical parameters included in the programs enhance swimming kinematics and thus improve swimming efficiency. Particularly, the development of these kinematic parameters directly correlates with the optimal swimming performance of adolescent swimmers ( 3 ). In the adolescent period, focusing on the development of excellent swimming techniques in swimmers is the first stage of achieving optimal performance ( 4 ). In addition to this developing a strong aerobic capacity is another important requirement of this ideal. There is limited research on aerobic-based training methods specifically applied to adolescent swimming performance. Furthermore, these limited studies mostly emphasize training loads with low and moderate aerobic development ( 5 ). These training loads contribute to submaximal swimming performance during adolescence. However, this type of training may be inadequate to meet the need for high speed-in adolescents ( 6 ). On the other hand, with the hormonal changes that occur in adolescence, interval training methods may be an effective option to maximize this speed requirement. This training approach optimizes the use of load and rest sets in swimming programs. Current literature suggested that high-intensity interval training simultaneously increases both aerobic and anaerobic endurance ( 7 , 8 ). However, these studies have generally been conducted on the adult swimmer population. The effects of interval training interventions on performance outcomes in adolescent swimmers with limited tolerance for high-intensity exercise ( 9 ) have been the subject of a few studies. The maximum aerobic swim speed (swMAS) is a critical performance parameter for the development of swimming-specific endurance. Scheduled long-distance swimming training in the SwMAS range of 85–95% is one of the most used training zones ( 10 ). Training in this domain is quite valuable for the development of oxygen utilization dynamics. High oxygen utilization capacity is vital for sustaining performance in competition distances of one minute and longer; this enhances the efficiency of energy production and improves the swimming economy ( 11 ). Another way to increase energy production efficiency is to improve stroke kinematic parameters. Parameters such as SL, SR, SI and index of coordination (IdC) are monitored in terms of studying the performance development of swimmers ( 12 ). SL is a parameter that plays an important role in making the energy used over a certain distance more efficient. This parameter contributes to maintaining performance for a longer duration by utilizing aerobic resources. There is a strong relationship between swim-specific aerobic power development and SL ( 13 ). Considering the lack of research examining the kinematic effects of long interval training loads on adolescent swimmers, especially in the training load and adaptations approach, and the weakness of the literature on interval training responses specific to adolescent swimmers, it becomes more essential to investigate the topic. With the approach presented above, this study aimed to investigate the effect of a six-week long interval training program on 100 m freestyle, maximal incremental swimming performance and stroke kinematic values in adolescent swimmers. Hypotheses of the study; i) LIT method will improve 100 m freestyle swimming performance in adolescent swimmers and improve SL, which is associated with aerobic capacity, and SI, which is associated with technical quality, among the parameters of stroke biomechanics, ii) it will reveal improvements in aerobic capacity through IdC and SI at different speed ranges in graded swimming performance. Materials and methods Subjects The study included nine adolescent competitive swimmers (height 159.72 ± 9.88 cm, body mass (BM) 48.84 ± 7.8 kg, and body mass index (BMI) 18.8 ± 1.6 kg/m 2 ), who regularly participated in training and competition. These swimmers had a regular training participation rate (90%) and had not been injured in the last six months. In addition, all included participants had previously experienced the tests performed and the training regime. Participants who did not meet these criteria were excluded from the study. The participants to be included in the study and the required sample size were determined using G-Power 3.1.9.4 software (14). The sample size required to evaluate the process effect of the planned intervention was determined based on an effect size of f = 0,8, an alpha (error) rate of 5%, and a power of 70% (15). As a result, it was determined that a total of seven people should be included in the study (16). The study had nine participants to minimize possible risks associated with measurements and statistical findings. The non-invasive research ethics committee of Dokuz Eylul University also approved the study, dated January 01, 2019, and numbered 2019/01–48. The study progressed throughout, adhering to the Helsinki Declaration. Informed consent forms were obtained from all participants and their legal guardians included in the study. Familiarization Session This session started with the warm-up protocol that lasted about approximately 15 minutes,1000 m.; [300 m (50 freestyle-50 backstroke)], afterward one minute of passive rest, 300 m kick and 300 m pull sets at varying speeds, and 25 m progressive swims to increase their speed). The 8x50 m graded swimming test began after the warm-up procedure. Swimmers were instructed to avoid strenuous physical activity for 48 hours before the tests, to sleep for at least 8 hours the day before the tests, and to stop consuming fluids and food 2 hours before the tests. The tests were performed at the same time, specifically between 16:00 and 18:00. All participants and their parents received detailed information about the experiments at the beginning of the familiarization session. All swimming tests and the six-week LIT intervention were performed in a 25 m swimming pool. The pool was maintained at a constant water temperature of 26–27°C and 40% relative humidity. Study Design The study design (Fig. 1) includes the 8x50 Meter GSP, Transition and Recovery Phase, and 100 Meter Freestyle Swimming Test measurements applied before and after the six-week intervention sessions. Data collection 8x50 Meter Graded Swimming Protocol (GSP) Following the in-water warm-up protocol, swimmers participated in an 8x50 m GSP. GSP was carried out by a national-level expert swimming coach and researcher who carried out the instant data recording processes. The swimmers were asked to start at a soft pace that they could maintain for a long time. In the other stages, the swimmers were asked to swim 1–2 s. faster than the previous stage. Swimmers were given 2 minutes for each 50 m. After completing the distance, the swimmer passively rested until the 2 minutes were completed. The total number of strokes used during each 50 m was also recorded. During the GSP, the swimmers' heart rates were measured with pulse variables taken from the carotid artery with a manually palpation for 10 seconds after each 50 m swim (17). In addition, perceived exertion level was determined with a 0–10 Borg scale in response to the question “How tired are you now?” to facilitate perception and application by adolescent swimmers. Level 1 was considered the lowest exertion level and level 10 was the highest exertion level (18). Transition and Recovery Phase After the GSP, a process involving 30 minutes of active and passive rest was carried out. This stage included 15 minutes of light self-paced tempo freestyle, and backstroke swimming, followed by a 15-minute passive rest period. 100 Meter Freestyle Swimming Performance 100 m freestyle swimming test was performed after the transition phase. 100 m freestyle swimming test was performed. To simulate a competitive environment, swimmers with similar swimming speeds performed the test in groups of three or two. An audio signal was presented on the output platform to start the tests. The swimmers' efforts and speeds were tracked by two stopwatches (FINIS) and its average was recorded (19). In addition, the test protocol was recorded with a video camera to calculate stroke kinematic values. After swimming 100 m, the swimmers' perceived exertion levels and heart rates were recorded. For the test to be considered valid, attention was paid to fulfilling the following three criteria: The individual best time is no more than two seconds away (main criteria). The heart rate should be at least 180 beats per minute ~%90 HR MAX (main criteria). The RPE should be at least 8 out of 10 (assist criteria) Stroke Kinematic Parameters Measurements The parameters of SR, SL, SI, and IdC were calculated utilizing the recorded stroke number and swimming speed parameters for the graded swimming and 100 m sprint test. Table I present the calculation methods for these parameters (20, 21). Training program during the intervention period This study was carried out after the completion of the general adaptation phase at the beginning of the season. At the start of the LIT program, swimmers trained six sessions per week, averaging four kilometers per session and a total of twenty-four kilometers per week. During this period, the energy systems were distributed using 90% aerobic domains [light-moderate aerobic, high aerobic,], 10% anaerobic domains [high-intensity interval training (HIIT)], and anaerobic power [very short distance with all-out effort] (22). In the aerobic domains, the study focused primarily on technical work, arm pull and leg kick sets, repetition methods at medium load, and long interval sets. The anaerobic domains used HIIT and anaerobic power sets. Using the basic training variables, it was possible to manipulate factors such as training volume and intensity during the 6-week mesocycle. This manipulation involved increasing volume by approximately 5% and increasing intensity by approximately 3% per week (20). Long Interval Training Intervention Swimmers were subjected to a long interval training load of 4x300 metres freestyle ( as fast as possible ) in 3 sessions per week. The intensity determined for loading was set in the range of 85–95% (HR 85–95%), corresponding to maximum or near-maximum effort (23). Rest time between repetitions was planned as a 1–1/2 work-rest ratio (~ 6 min @). Based on the overload principle, a speed increase of ~ 3 seconds in repetitions was applied over 2 weeks. Verification of the intensity applied was achieved by 10-second pulse checks between each repetition and observation of skin color. It was ensured that the pulse rate was 28–30 beats (range between 168–180 beats per minute), and the facial and dorsal skin tone was observed as ‘ red ’ (24). Statistical Analyses All statistical analyses were performed with the JASP (version 0.16.4) statistical package program. The Shapiro-Wilk test was applied to determine the normal distribution of all participants' kinematic parameters data (SC, SR, SL, SI, IdC). It was determined that the data were normally distributed. A paired sample T-test was applied to the pre and post-tests to determine the development of the graded swimming and 100 m sprint tests. Cohen's d was used to determine the effect sizes between the data and comparisons were made. In statistical analyses, the significance level was determined as less than 0.05 (25). Results The study included nine swimmers (7 boys, 2 girls) with a mean age of 13.55 ± 1.42 years, who had been training regularly for at least 3 years. The mean height 159.72 ± 9.88 cm, body weight 48.84 ± 7.8 kg and body mass index 18.8 ± 1.6 kg/m2 of the swimmers. No significant change was observed in anthropometric values after the intervention. LIT intervention significantly improved swimming velocity (m/sec) (p=0.006) and 100 m swimming time (p=0.010) among 100 m freestyle swimming performance values. Stroke kinematic values; SL (p=0.028) and SI (p=0.006) changed significantly, while IdC (pre=0.016±0.005, post= 0.017±0.005) and SR changed modestly (-1.14 stroke/min). In addition, RPE and heart rate values decreased significantly after the test. It is shown in table II. Figure II shows the factors determined as parameters in the 100 m freestyle swimming test after LIT. After a LIT intervention, the swimming time improved in all stages of the GSP (table III) (p 1 =0.014, p 2 =0.002, p 3 <.001, p 4 <.001, p 5 <.001, p 6 <.001, p 7 =0.002, p 8 <.001). In the first two stages, the stroke length parameter significantly improved (p 1 =0.011, p 2 =0.028) while there was a numerical improvement in all other stages. The initial six stages of the stroke index values indicated significant enhancement. (p 1 =0.002, p 2 <.001, p 3 =0.005, p 4 =0.006, p 5 =0.009, p 6 =0.084). Numerical improvement was noted in the final two phases. The IdC parameters in stages 2, 3, and 4 revealed statistical differences (p 1 =0.035, p 2 =0.013, and p 3 =0.035). Graph I illustrates changes in the swimmers' GSP swimming speed. Following the LIT intervention, swimming speed was enhanced in every phase. The stroke index parameters following the LIT intervention are presented as a line graph in Graph II The swimmers' stroke index values showed statistically significant improvement during the initial six phases. Also, at every stage, the post-test results were improved than the pre-test values. The SI parameters in the post-test exhibited reduced fluctuation compared to the pre-test and demonstrated more stable progression. Discussion The study aimed to investigate the effect of LIT methods on the kinematic and performance outcomes of 100 m freestyle swimming and graded swimming protocols in adolescent swimmers. The main finding of the study was that the long interval training method positively affected both swimming performances through aerobic capacity gain and improved the kinematic parameters SI and SL. It was also found that IdC is a critical indicator of upper extremity coordination during swimming in adolescent swimmers and this change can be observed more clearly in graded swimming models. Effects of Long Interval Training on 100 meters swimming performance and kinematic parameters In the study, 6-week long interval training improved 100 m swimming performance (p = 0.010). When the kinematic reflections underlying this improvement were evaluated, it was observed that SL (p = 0.028) and SI (p = 0.006) improved significantly. Studies have shown that young swimmers utilize 55% anaerobic and 45% anaerobic energy pathways during the 100 m freestyle performance, and aerobic capacity is an important determinant of performance ( 26 ). In addition, the critical role of critical speed, which is an indicator of aerobic capacity, in the emergence of performance has been proven in previous studies( 27 , 28 ). In studies on training models, Dalamitros et al. showed that 8-week long interval training loads planned over 100 m repetitions improved 100 m. freestyle swimming performance in adult swimmers (CI95%= − 0.50 to -5.10 ES = 0.59) and that the technical reflection of this improvement was in Stroke length values. In addition, it was found that the Stroke Rate was not affected in the study ( 29 ). In our study, a 6-week long interval training protocol planned on 300 m. repetitions indicates improvements like the presented literature (p Velocity =.0.006, d= -1.21), (p SL =0.028, Cohen’s d= -0.88). In addition, the SI (p SI =0,006, Cohen's d=-1,22) improvements obtained in our study showed that it is a critical stroke kinematic parameter in monitoring 100 m swimming performance. Long interval training practices increased aerobic contribution in 100 m freestyle performance in adolescent swimmers and the reflection of increased efficiency on stroke kinematics improved SL values, especially SI. In addition, a significant decrease in physiological heart rate values and a significant decrease in perceived difficulty level are other responses confirming this information. The results emphasize the importance of SI for adolescent swimmers to utilize aerobic resources with high efficiency and to monitor their technical development. On the other hand, the fact that there was no change in the kinematic value directly affected by neuromuscular contributions such as SR (p SR =0,280, Cohen's d = 0,38) indicates that the training protocol applied for anaerobic power production was insufficient. Effects of Long Interval Training on Graded Swimming Protocol The difficulty of completing test protocols based on long-distance (e.g. 5x200-7x200 incremental swim tests) in adolescent swimmers poses some difficulties in following the physiological and kinematic changes specific to this age. In particular, the small body area compared to adult swimmers and the earlier onset of aerobic contribution ( 30 ). indicate the need for a modification in the test protocol. In addition, in a recent study, it has been suggested that the 400 m time trial test in age group swimmers is like the aerobic power values obtained in graded interval tests and can be used to evaluate aerobic power and stroke kinematics in a shorter time and efficiently ( 1 ). We emphasize the need for the development of age-specific test protocols and validity and reliability studies in future research. The efforts in the 8x50m graded swimming protocol, which we adapted by the nature of incremental tests, were aimed at monitoring more aerobic capacity due to the gradual increase in speed. Generally, the effort reached in the last stage is like the physiological ( 31 ) and kinematic values (Idc = 0.029 (superposition), SR = 68.5) in which the ‘severe domain’ interval (RPE: 6.7-HR: 163 bpm) is entered between the critical swimming speed and in-water VO 2max thresholds ( 32 ). In our study, swimming speed improved significantly at each stage of the protocol due to the long interval training. In terms of kinematics, it was observed that the SI value improved significantly in the first 6 stages. From a holistic point of view, it was observed that SI fluctuation between stages decreased and progressed more steadily (Graphic 2). This information showed that swimming stroke quality improved and behaved more stable in different metabolic stages within aerobic capacity. In addition, the significant improvement in SL in stages 1 and 2 and the moderate improvement in the other stages were considered to indicate that aerobic power improved during the total protocol ( 32 ). Adolescent swimmers responded to the increasing speed demands between the stages without increasing their SR values. The fact that SR did not change significantly, especially in the last stages, may indicate that training did not contribute to significant speed improvements. Since an increase in SR indicates an increase in the utilization of anaerobic resources in progressive tests ( 13 ), the lack of change in this parameter supports the holistic idea described above. In addition, the fact that the SI parameter is the most improved value in the GST, like the 100 m swim test, has the potential to help the observation of aerobic contribution and technique in adolescent swimming performance and the observation of heavy to severe and severe to extreme exercise domain changes through the breakpoints between efforts. This information is critical for coaches to observe the kinematic responses of the swimmer to these domains during effort. In recent swimming kinematics studies, IdC, which shows stroke synchronization, has taken an important place ( 31 , 33 ). IdC shows the delay of the strokes during the propulsive phases during the freestyle technique and provides information about 3 different stroke positions through the synchronization of the strokes [IDC 0 superposition] ( 33 ). Although the opposition feels more comfortable, it is reported that the efficiency of energy expenditure increases as you move to superposition. Especially in high- level swimmers, superposition values are accepted as an indicator of the maturation of the strokes, improvement of motor control, and increased efficiency of traction phases ( 33 ). In our study, there was no increase in the pre-test (mean = 0.016) and post-test (mean = 0.017) values of the 100 m test (Cohen's d = 0.33) but significant improvement in the 2nd, 3rd, and 4th stages in the GST was thought to indicate that it is more appropriate to evaluate stroke coordination and synchronization in adolescent swimmers through IdC in graded loads. In addition, target speed points can be determined in training in the stages where no improvement is observed and the development of coordination at these speeds can be monitored on IdC. Limitation Since the study focuses on the performance and kinematic reflections of LIT, there is no information about the growth and development levels of the participants. In addition, although the small number of participants seems to be another limitation, the difficulty of reaching similar age groups of swimmers who train regularly and recent studies with a similar number of participants ( 31 , 34 ) draws attention to the need for scientific studies in the field. Another limitation of the study is the absence of a control group. The researchers thought that the potential effect of the high training load in the manipulation could cause changes in the measured parameters and the performance levels of adolescent swimmers showed a wide distribution. Conclusion The findings suggest that LIT is a key method to improve 100 m swimming performance and speeds in the GST phases through aerobic contribution and improved stroke kinematics in adolescent swimmers. LIT was observed to improve the IdC values, especially SI, in the SL and graded swim test. The more stable trend of the SI value in the first six stages of the GST was characterized as a reflection of the improvement of aerobic capacity on the stroke technique. In addition, the fact that SI did not change in the last two stages was thought to reflect the swimmers' increased energy requirement due to the metabolic changes in the exercise domain. Again, findings emphasize that IdC should be monitored at different speed ranges during progressive tests in adolescent swimmers in the follow-up of stroke coordination development. On the other hand, the fact that LIT did not change SR in both tests indicates that coaches should also include anaerobic power development in their programs through neuromuscular-based studies and all-out effort studies applied at short distances (such as 10–25 m) with alactacid metabolism. In future studies, metabolic and kinematic evaluations of different interval training strategies in adolescent swimmers are needed. Declarations Authors' contribution Author Contributions: E.D., E.U. and E.G. designed the study. E.D. obtained the data. E.U. and E.D. analyzed the data. E.U., E.D., E.G. interpreted the results and drafted the manuscript. E.U., E.G. supervised the study. All authors contributed to the review and revision of the manuscript and agree to be accountable for all aspects of the work, ensuring integrity and accuracy. All authors have read and agreed to the published version of the manuscript. Data availability statement The data of this study were used only for scientific purposes and participant information was kept confidential. The findings of this study are supported by raw data, which the corresponding author is willing to share upon reasonable request. The sharing of data will be decided based on the principles of ethics and confidentiality, and may be given to editors or reviewers if asked for. Declaration of AI Use: Grammarly and ChatGPT4.0 were used by the authors during the preparation of this work to improve its readability and language. The authors then reviewed and edited the content as needed and took full responsibility for the publication's content. Declaration of conflicting interests The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Ethical Approval: The non-invasive research ethics committee of Dokuz Eylul University also approved the study, dated January 01, 2019, and numbered 2019/01-48. The study progressed throughout, adhering to the Helsinki Declaration. Funding The author(s) received no financial support for the research, authorship, and/or publication of this article. Practical Application In adolescent swimmers, technical and aerobic power are dependent values that develop together. 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Oxygen uptake kinetics in children and adolescents: A review. Pediatr. Exerc. Sci. 21 (2), 130–143. https://doi.org/10.1123/pes.21.2.130 (2009). Fernandes, R. J., Carvalho, D. D. & Figueiredo, P. Training zones in competitive swimming: A biophysical approach. Front. Sports Act. Living . 6 , 1363730. https://doi.org/10.3389/fspor.2024.1363730 (2024). Potdevin, F., Bril, B., Sidney, M. & Pelayo, P. Stroke frequency and arm coordination in front crawl swimming. Int. J. Sports Med. 27 (3), 193–198. https://doi.org/10.1055/s-2005-837545 (2006). Chollet, D., Chalies, S. & Chatard, J. C. A new index of coordination for the crawl: description and usefulness. Int. J. Sports Med. 21 (1), 54–59. https://doi.org/10.1055/s-2000-8888 (2000). Fiori, J. M., Bandeira, P. F. R., Zacca, R. & de Castro, S. The impact of a swimming training season on anthropometrics, maturation, and kinematics in 12-year-old and under age-group swimmers: A network analysis. Front. Sports Act. Living . 4 , 799690. https://doi.org/10.3389/fspor.2022.799690 (2022). Tables Tables 1 to 3 are available in the Supplementary Files section. Graphics Graphics 1 and 2 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Tablesandgraphics.docx 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-6750664","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":473229795,"identity":"d33e9c1d-6aed-46b4-8f25-8533d8408dcf","order_by":0,"name":"Esila Durğut Yalın","email":"","orcid":"","institution":"Manisa Celal Bayar University","correspondingAuthor":false,"prefix":"","firstName":"Esila","middleName":"Durğut","lastName":"Yalın","suffix":""},{"id":473229796,"identity":"7bb8a859-91fa-4f1f-86bb-10721f1526a5","order_by":1,"name":"Erdem Uylas","email":"","orcid":"","institution":"Dokuz Eylul University","correspondingAuthor":false,"prefix":"","firstName":"Erdem","middleName":"","lastName":"Uylas","suffix":""},{"id":473229797,"identity":"ecff88cf-43d9-48bb-ad37-cfb4ff9a29a9","order_by":2,"name":"Erkan Günay","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA9ElEQVRIiWNgGAWjYFACNjiL8QFjA4hOIF4LswFcywEitbBJEKWFX/pY4ucChtrE7exnzCp+7jjMwM+eY8D8cQ9uLZJ9aYelZzAcT9zZk2N2s/fMYQbJnjcGDAee4dZicIa9QZqH4VjihgM5ZrcZ2w4zGNzIAWrB4zL7M+zNv8Fazr8xKwZpsSekxYCH7RjQlprEDTdyzJjBtkgQ0CJxhi3NmsfggPGGG8+KJXvPpPNInHlWcOAMHi38PWzGt3kq6mQ3nE/e+OHnDms5/vbkjQ8q8GiBOu8wkOAwADF5QARBDUBQB8TsD4hQOApGwSgYBSMRAAAkClTcNNzoGQAAAABJRU5ErkJggg==","orcid":"","institution":"Manisa Celal Bayar University","correspondingAuthor":true,"prefix":"","firstName":"Erkan","middleName":"","lastName":"Günay","suffix":""}],"badges":[],"createdAt":"2025-05-26 12:08:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6750664/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6750664/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":85075528,"identity":"5503ace4-1657-4ba8-aa32-97e21c39116f","added_by":"auto","created_at":"2025-06-20 16:32:07","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":86433,"visible":true,"origin":"","legend":"\u003cp\u003eStudy Design\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6750664/v1/868e60b19427b4d8a9bf7cca.jpg"},{"id":85075530,"identity":"09d3ae7a-164b-4fe0-9e63-a4f3075dc33e","added_by":"auto","created_at":"2025-06-20 16:32:07","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":29207,"visible":true,"origin":"","legend":"\u003cp\u003eStroke kinematic parameters and swim time and velocity values of 100 m freestyle swimming tests\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6750664/v1/f7a385362105fc4c4fc58dee.jpg"},{"id":86736360,"identity":"6b3e4ec7-c294-436e-9d7c-1fc83624eda8","added_by":"auto","created_at":"2025-07-15 05:43:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":771063,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6750664/v1/248476d9-a888-4691-8b82-d222dd0323b5.pdf"},{"id":85076283,"identity":"ba4deb59-5298-4f26-9bfd-e4cb38558592","added_by":"auto","created_at":"2025-06-20 16:40:07","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":95495,"visible":true,"origin":"","legend":"","description":"","filename":"Tablesandgraphics.docx","url":"https://assets-eu.researchsquare.com/files/rs-6750664/v1/45e699521729d5d9c37e1f60.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"The Effect of Long Interval Training on Swimming Performance and Stroke Kinematics in Adolescent Swimmers","fulltext":[{"header":"Introduction","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eOptimal swimming performance requires determining different age groups physiological and physical needs. For arrival, the optimal performance depends on steady progression and the use of corresponding training methods. Age-related physiological changes in adolescent swimmers should be considered to achieve optimal performance in all these training methods (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). These training methods improve the efficiency of recovery by increasing muscle strength and endurance (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). For the development of these physiological processes, swimming-specific technical parameters should be included in training programs. Technical parameters included in the programs enhance swimming kinematics and thus improve swimming efficiency. Particularly, the development of these kinematic parameters directly correlates with the optimal swimming performance of adolescent swimmers (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). In the adolescent period, focusing on the development of excellent swimming techniques in swimmers is the first stage of achieving optimal performance (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). In addition to this developing a strong aerobic capacity is another important requirement of this ideal. There is limited research on aerobic-based training methods specifically applied to adolescent swimming performance. Furthermore, these limited studies mostly emphasize training loads with low and moderate aerobic development (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). These training loads contribute to submaximal swimming performance during adolescence. However, this type of training may be inadequate to meet the need for high speed-in adolescents (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). On\u003c/p\u003e \u003cp\u003ethe other hand, with the hormonal changes that occur in adolescence, interval training methods may be an effective option to maximize this speed requirement. This training approach optimizes the use of load and rest sets in swimming programs. Current literature suggested that high-intensity interval training simultaneously increases both aerobic and anaerobic endurance (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). However, these studies have generally been conducted on the adult swimmer population. The effects of interval training interventions on performance outcomes in adolescent swimmers with limited tolerance for high-intensity exercise (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e) have been the subject of a few studies.\u003c/p\u003e \u003cp\u003eThe maximum aerobic swim speed (swMAS) is a critical performance parameter for the development of swimming-specific endurance. Scheduled long-distance swimming training in the SwMAS range of 85\u0026ndash;95% is one of the most used training zones (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Training in this domain is quite valuable for the development of oxygen utilization dynamics. High oxygen utilization capacity is vital for sustaining performance in competition distances of one minute and longer; this enhances the efficiency of energy production and improves the swimming economy (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). Another way to increase energy production efficiency is to improve stroke kinematic parameters. Parameters such as SL, SR, SI and index of coordination (IdC) are monitored in terms of studying the performance development of swimmers (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). SL is a parameter that plays an important role in making the energy used over a certain distance more efficient. This parameter contributes to maintaining performance for a longer duration by utilizing aerobic resources. There is a strong relationship between swim-specific aerobic power development and SL (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eConsidering the lack of research examining the kinematic effects of long interval training loads on adolescent swimmers, especially in the training load and adaptations approach, and the weakness of the literature on interval training responses specific to adolescent swimmers, it becomes more essential to investigate the topic. With the approach presented above, this study aimed to investigate the effect of a six-week long interval training program on 100 m freestyle, maximal incremental swimming performance and stroke kinematic values in adolescent swimmers. Hypotheses of the study; i) LIT method will improve 100 m freestyle swimming performance in adolescent swimmers and improve SL, which is associated with aerobic capacity, and SI, which is associated with technical quality, among the parameters of stroke biomechanics, ii) it will reveal improvements in aerobic capacity through IdC and SI at different speed ranges in graded swimming performance.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\"\u003e\n \u003ch2\u003eSubjects\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe study included nine adolescent competitive swimmers (height 159.72\u0026thinsp;\u0026plusmn;\u0026thinsp;9.88 cm, body mass (BM) 48.84\u0026thinsp;\u0026plusmn;\u0026thinsp;7.8 kg, and body mass index (BMI) 18.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 kg/m\u003csup\u003e2\u003c/sup\u003e), who regularly participated in training and competition. These swimmers had a regular training participation rate (90%) and had not been injured in the last six months. In addition, all included participants had previously experienced the tests performed and the training regime. Participants who did not meet these criteria were excluded from the study.\u003c/p\u003e\n \u003cp\u003eThe participants to be included in the study and the required sample size were determined using G-Power 3.1.9.4 software (14). The sample size required to evaluate the process effect of the planned intervention was determined based on an effect size of f\u0026thinsp;=\u0026thinsp;0,8, an alpha (error) rate of 5%, and a power of 70% (15). As a result, it was determined that a total of seven people should be included in the study (16). The study had nine participants to minimize possible risks associated with measurements and statistical findings. The non-invasive research ethics committee of Dokuz Eylul University also approved the study, dated January 01, 2019, and numbered 2019/01\u0026ndash;48. The study progressed throughout, adhering to the Helsinki Declaration. Informed consent forms were obtained from all participants and their legal guardians included in the study.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003ch3\u003eFamiliarization Session\u003c/h3\u003e\n\u003cdiv\u003e\n \u003cp\u003eThis session started with the warm-up protocol that lasted about approximately 15 minutes,1000 m.; [300 m (50 freestyle-50 backstroke)], afterward one minute of passive rest, 300 m kick and 300 m pull sets at varying speeds, and 25 m progressive swims to increase their speed). The 8x50 m graded swimming test began after the warm-up procedure.\u003c/p\u003e\n \u003cp\u003eSwimmers were instructed to avoid strenuous physical activity for 48 hours before the tests, to sleep for at least 8 hours the day before the tests, and to stop consuming fluids and food 2 hours before the tests. The tests were performed at the same time, specifically between 16:00 and 18:00. All participants and their parents received detailed information about the experiments at the beginning of the familiarization session. All swimming tests and the six-week LIT intervention were performed in a 25 m swimming pool. The pool was maintained at a constant water temperature of 26\u0026ndash;27\u0026deg;C and 40% relative humidity.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eStudy Design\u003c/h3\u003e\n\u003cdiv\u003e\n \u003cp\u003eThe study design (Fig. 1) includes the 8x50 Meter GSP, Transition and Recovery Phase, and 100 Meter Freestyle Swimming Test measurements applied before and after the six-week intervention sessions.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\"\u003e\n \u003ch2\u003eData collection\u003c/h2\u003e\n \u003cdiv id=\"Sec8\"\u003e\n \u003ch2\u003e8x50 Meter Graded Swimming Protocol (GSP)\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eFollowing the in-water warm-up protocol, swimmers participated in an 8x50 m GSP. GSP was carried out by a national-level expert swimming coach and researcher who carried out the instant data recording processes. The swimmers were asked to start at a soft pace that they could maintain for a long time. In the other stages, the swimmers were asked to swim 1\u0026ndash;2 s. faster than the previous stage. Swimmers were given 2 minutes for each 50 m. After completing the distance, the swimmer passively rested until the 2 minutes were completed. The total number of strokes used during each 50 m was also recorded. During the GSP, the swimmers\u0026apos; heart rates were measured with pulse variables taken from the carotid artery with a manually palpation for 10 seconds after each 50 m swim (17). In addition, perceived exertion level was determined with a 0\u0026ndash;10 Borg scale in response to the question \u0026ldquo;How tired are you now?\u0026rdquo; to facilitate perception and application by adolescent swimmers. Level 1 was considered the lowest exertion level and level 10 was the highest exertion level (18).\u003c/p\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003ch3\u003eTransition and Recovery Phase\u003c/h3\u003e\n\u003cdiv\u003e\n \u003cp\u003eAfter the GSP, a process involving 30 minutes of active and passive rest was carried out. This stage included 15 minutes of light self-paced tempo freestyle, and backstroke swimming, followed by a 15-minute passive rest period.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003e100 Meter Freestyle Swimming Performance\u003c/h3\u003e\n\u003cdiv\u003e\n \u003cp\u003e100 m freestyle swimming test was performed after the transition phase. 100 m freestyle swimming test was performed. To simulate a competitive environment, swimmers with similar swimming speeds performed the test in groups of three or two. An audio signal was presented on the output platform to start the tests. The swimmers\u0026apos; efforts and speeds were tracked by two stopwatches (FINIS) and its average was recorded (19). In addition, the test protocol was recorded with a video camera to calculate stroke kinematic values. After swimming 100 m, the\u003c/p\u003e\n \u003cp\u003eswimmers\u0026apos; perceived exertion levels and heart rates were recorded. For the test to be considered valid, attention was paid to fulfilling the following three criteria:\u003c/p\u003e\n\u003c/div\u003e\n\u003cul\u003e\n \u003cli\u003e\n \u003cp\u003eThe individual best time is no more than two seconds away (main criteria).\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eThe heart rate should be at least 180 beats per minute ~%90 HR\u003csub\u003eMAX\u003c/sub\u003e (main criteria).\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eThe RPE should be at least 8 out of 10 (assist criteria)\u003c/p\u003e\n \u003c/li\u003e\n\u003c/ul\u003e\n\u003cdiv id=\"Sec11\"\u003e\n \u003ch2\u003eStroke Kinematic Parameters Measurements\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe parameters of SR, SL, SI, and IdC were calculated utilizing the recorded stroke number and swimming speed parameters for the graded swimming and 100 m sprint test. Table I present the calculation methods for these parameters (20, 21).\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\"\u003e\n \u003cdiv id=\"Sec13\"\u003e\n \u003ch2\u003eTraining program during the intervention period\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eThis study was carried out after the completion of the general adaptation phase at the beginning of the season. At the start of the LIT program, swimmers trained six sessions per week, averaging four kilometers per session and a total of twenty-four kilometers per week. During this period, the energy systems were distributed using 90% aerobic domains [light-moderate aerobic, high aerobic,], 10% anaerobic domains [high-intensity interval training (HIIT)], and anaerobic power [very short distance with all-out effort] (22). In the aerobic domains, the study focused primarily on technical work, arm pull and leg kick sets, repetition methods at medium load, and long interval sets. The anaerobic domains used HIIT and anaerobic power sets. Using the basic training variables, it was possible to manipulate factors such as training volume and intensity during the 6-week mesocycle. This manipulation involved increasing volume by approximately 5% and increasing intensity by approximately 3% per week (20).\u003c/p\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec14\"\u003e\n \u003ch2\u003eLong Interval Training Intervention\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eSwimmers were subjected to a long interval training load of 4x300 metres freestyle (\u003cem\u003eas fast as possible\u003c/em\u003e) in 3 sessions per week. The intensity determined for loading was set in the range of 85\u0026ndash;95% (HR 85\u0026ndash;95%), corresponding to maximum or near-maximum effort (23). Rest time between repetitions was planned as a 1\u0026ndash;1/2 work-rest ratio (~\u0026thinsp;6 min @). Based on the overload principle, a speed increase of ~\u0026thinsp;3 seconds in repetitions was applied over 2 weeks. Verification of the intensity applied was achieved by 10-second pulse checks between each repetition and observation of skin color. It was ensured that the pulse rate was 28\u0026ndash;30 beats (range between 168\u0026ndash;180 beats per minute), and the facial and dorsal skin tone was observed as \u0026lsquo;\u003cem\u003ered\u003c/em\u003e\u0026rsquo; (24).\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec15\"\u003e\n \u003ch2\u003eStatistical Analyses\u003c/h2\u003e\n \u003cdiv\u003e\n \u003cp\u003eAll statistical analyses were performed with the JASP (version 0.16.4) statistical package program. The Shapiro-Wilk test was applied to determine the normal distribution of all participants\u0026apos; kinematic parameters data (SC, SR, SL, SI, IdC). It was determined that the data were normally distributed. A paired sample T-test was applied to the pre and post-tests to determine the development of the graded swimming and 100 m sprint tests. Cohen\u0026apos;s d was used to determine the effect sizes between the data and comparisons were made. In statistical analyses, the significance level was determined as less than 0.05 (25).\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThe study included nine swimmers (7 boys, 2 girls) with a mean age of 13.55 \u0026plusmn; 1.42 years, who had been training regularly for at least 3 years. The mean height 159.72 \u0026plusmn; 9.88 cm, body weight\u003c/p\u003e\n\u003cp\u003e48.84 \u0026plusmn; 7.8 kg and body mass index 18.8 \u0026plusmn; 1.6 kg/m2 of the swimmers. No significant change was observed in anthropometric values after the intervention.\u003c/p\u003e\n\u003cp\u003eLIT intervention significantly improved swimming velocity (m/sec) (p=0.006) and 100 m swimming time (p=0.010) among 100 m freestyle swimming performance values. Stroke kinematic values; SL (p=0.028) and SI (p=0.006) changed significantly, while IdC (pre=0.016\u0026plusmn;0.005, post= 0.017\u0026plusmn;0.005) and SR changed modestly (-1.14 stroke/min). In addition, RPE and heart rate values decreased significantly after the test. It is shown in table II. Figure II shows the factors determined as parameters in the 100 m freestyle swimming test after LIT.\u003c/p\u003e\n\u003cp\u003eAfter a LIT intervention, the swimming time improved in all stages of the GSP (table III) (p\u003csub\u003e1\u003c/sub\u003e=0.014, p\u003csub\u003e2\u003c/sub\u003e=0.002, p\u003csub\u003e3\u003c/sub\u003e\u0026lt;.001, p\u003csub\u003e4\u003c/sub\u003e\u0026lt;.001, p\u003csub\u003e5\u003c/sub\u003e\u0026lt;.001, p\u003csub\u003e6\u003c/sub\u003e\u0026lt;.001, p\u003csub\u003e7\u003c/sub\u003e=0.002, p\u003csub\u003e8\u003c/sub\u003e\u0026lt;.001). In the first two\u003c/p\u003e\n\u003cp\u003estages, the stroke length parameter significantly improved (p\u003csub\u003e1\u003c/sub\u003e=0.011, p\u003csub\u003e2\u003c/sub\u003e=0.028) while there was a numerical improvement in all other stages. The initial six stages of the stroke index values indicated significant enhancement. (p\u003csub\u003e1\u003c/sub\u003e=0.002, p\u003csub\u003e2\u003c/sub\u003e\u0026lt;.001, p\u003csub\u003e3\u003c/sub\u003e=0.005, p\u003csub\u003e4\u003c/sub\u003e=0.006, p\u003csub\u003e5\u003c/sub\u003e=0.009, p\u003csub\u003e6\u003c/sub\u003e=0.084). Numerical improvement was noted in the final two phases. The IdC parameters in stages 2, 3, and 4 revealed statistical differences (p\u003csub\u003e1\u003c/sub\u003e=0.035, p\u003csub\u003e2\u003c/sub\u003e=0.013, and p\u003csub\u003e3\u003c/sub\u003e=0.035).\u003c/p\u003e\n\u003cp\u003eGraph I illustrates changes in the swimmers\u0026apos; GSP swimming speed. Following the LIT intervention, swimming speed was enhanced in every phase.\u003c/p\u003e\n\u003cp\u003eThe stroke index parameters following the LIT intervention are presented as a line graph in Graph II The swimmers\u0026apos; stroke index values showed statistically significant improvement during the initial six phases. Also, at every stage, the post-test results were improved than the pre-test values. The SI parameters in the post-test exhibited reduced fluctuation compared to the pre-test and demonstrated more stable progression.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe study aimed to investigate the effect of LIT methods on the kinematic and performance outcomes of 100 m freestyle swimming and graded swimming protocols in adolescent swimmers. The main finding of the study was that the long interval training method positively affected both swimming performances through aerobic capacity gain and improved the kinematic parameters SI and SL. It was also found that IdC is a critical indicator of upper extremity coordination during swimming in adolescent swimmers and this change can be observed more clearly in graded swimming models.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003eEffects of Long Interval Training on 100 meters swimming performance and kinematic parameters\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eIn the study, 6-week long interval training improved 100 m swimming performance (p\u0026thinsp;=\u0026thinsp;0.010). When the kinematic reflections underlying this improvement were evaluated, it was observed that SL (p\u0026thinsp;=\u0026thinsp;0.028) and SI (p\u0026thinsp;=\u0026thinsp;0.006) improved significantly. Studies have shown that young swimmers utilize 55% anaerobic and 45% anaerobic energy pathways during the 100 m freestyle performance, and aerobic capacity is an important determinant of performance (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e). In addition, the critical role of critical speed, which is an indicator of aerobic capacity, in the emergence of performance has been proven in previous studies(\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e). In studies on training models, Dalamitros et al. showed that 8-week long interval training loads planned over 100 m repetitions improved 100 m. freestyle swimming performance in adult swimmers (CI95%= \u0026minus;\u0026thinsp;0.50 to -5.10 ES\u0026thinsp;=\u0026thinsp;0.59) and that the technical reflection of this improvement was in Stroke length values. In addition, it was found that the Stroke Rate was not affected in the study (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e). In our study, a 6-week long interval training protocol planned on 300 m. repetitions indicates improvements like the presented literature (p\u003csub\u003eVelocity\u003c/sub\u003e=.0.006, d= -1.21), (p\u003csub\u003eSL\u003c/sub\u003e=0.028, Cohen\u0026rsquo;s d=\u003c/p\u003e \u003cp\u003e-0.88). In addition, the SI (p\u003csub\u003eSI\u003c/sub\u003e =0,006, Cohen's d=-1,22) improvements obtained in our study showed that it is a critical stroke kinematic parameter in monitoring 100 m swimming performance. Long interval training practices increased aerobic contribution in 100 m freestyle performance in adolescent swimmers and the reflection of increased efficiency on stroke kinematics improved SL values, especially SI. In addition, a significant decrease in physiological heart rate values and a significant decrease in perceived difficulty level are other responses confirming this information. The results emphasize the importance of SI for adolescent swimmers to utilize aerobic resources with high efficiency and to monitor their technical development. On the other hand, the fact that there was no change in the kinematic value directly affected by neuromuscular contributions such as SR (p\u003csub\u003eSR\u003c/sub\u003e=0,280, Cohen's d\u0026thinsp;=\u0026thinsp;0,38) indicates that the training protocol applied for anaerobic power production was insufficient.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003eEffects of Long Interval Training on Graded Swimming Protocol\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe difficulty of completing test protocols based on long-distance (e.g. 5x200-7x200 incremental swim tests) in adolescent swimmers poses some difficulties in following the physiological and kinematic changes specific to this age. In particular, the small body area compared to adult swimmers and the earlier onset of aerobic contribution (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e). indicate the need for a modification in the test protocol. In addition, in a recent study, it has been suggested that the 400 m time trial test in age group swimmers is like the aerobic power values obtained in graded interval tests and can be used to evaluate aerobic power and stroke kinematics in a shorter time and efficiently (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). We emphasize the need for the development of age-specific test protocols and validity and reliability studies in future research. The efforts in the 8x50m graded swimming protocol, which we adapted by the nature of incremental tests, were aimed at monitoring more aerobic capacity due to the gradual increase in speed. Generally, the effort reached in the last stage is like the physiological (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e) and kinematic values (Idc\u0026thinsp;=\u0026thinsp;0.029 (superposition), SR\u0026thinsp;=\u0026thinsp;68.5) in which the \u0026lsquo;severe domain\u0026rsquo; interval (RPE: 6.7-HR: 163 bpm) is entered between the critical swimming speed and in-water VO\u003csub\u003e2max\u003c/sub\u003e thresholds (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn our study, swimming speed improved significantly at each stage of the protocol due to the long interval training. In terms of kinematics, it was observed that the SI value improved significantly in the first 6 stages. From a holistic point of view, it was observed that SI fluctuation between stages decreased and progressed more steadily (Graphic 2). This information showed that swimming stroke quality improved and behaved more stable in different metabolic stages within aerobic capacity. In addition, the significant improvement in SL in stages 1 and 2 and the moderate improvement in the other stages were considered to indicate that aerobic power improved during the total protocol (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e). Adolescent swimmers responded to the increasing speed demands between the stages without increasing their SR values. The fact that SR did not change significantly, especially in the last stages, may indicate that training did not contribute to significant speed improvements. Since an increase in SR indicates an increase in the utilization of anaerobic resources in progressive tests (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e), the lack of change in this parameter supports the holistic idea described above. In addition, the fact that the SI parameter is the most improved value in the GST, like the 100 m swim test, has the potential to help the observation of aerobic contribution and technique in adolescent swimming performance and the observation of heavy to severe and severe to extreme exercise domain changes through the breakpoints between efforts. This information is critical for coaches to observe the kinematic responses of the swimmer to these domains during effort.\u003c/p\u003e \u003cp\u003eIn recent swimming kinematics studies, IdC, which shows stroke synchronization, has taken an important place (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e). IdC shows the delay of the strokes during the propulsive phases during the freestyle technique and provides information about 3 different stroke positions through the synchronization of the strokes [IDC\u0026thinsp;\u0026lt;\u0026thinsp;0 catch-up position, IDC\u0026thinsp;=\u0026thinsp;0 opposition, IDC\u0026thinsp;\u0026gt;\u0026thinsp;0 superposition] (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e). Although the opposition feels more comfortable, it is reported that the efficiency of energy expenditure increases as you move to superposition. Especially in high- level swimmers, superposition values are accepted as an indicator of the maturation of the strokes, improvement of motor control, and increased efficiency of traction phases (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e). In our study, there was no increase in the pre-test (mean\u0026thinsp;=\u0026thinsp;0.016) and post-test (mean\u0026thinsp;=\u0026thinsp;0.017) values of the 100 m test (Cohen's d\u0026thinsp;=\u0026thinsp;0.33) but significant improvement in the 2nd, 3rd, and 4th stages in the GST was thought to indicate that it is more appropriate to evaluate stroke coordination and synchronization in adolescent swimmers through IdC in graded loads. In addition, target speed points can be determined in training in the stages where no improvement is observed and the development of coordination at these speeds can be monitored on IdC.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section2\"\u003e \u003ch2\u003eLimitation\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eSince the study focuses on the performance and kinematic reflections of LIT, there is no information about the growth and development levels of the participants. In addition, although the small number of participants seems to be another limitation, the difficulty of reaching similar age groups of swimmers who train regularly and recent studies with a similar number of participants (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e) draws attention to the need for scientific studies in the field. Another limitation of the study is the absence of a control group. The researchers thought that the potential effect of the high training load in the manipulation could cause changes in the measured parameters and the performance levels of adolescent swimmers showed a wide distribution.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe findings suggest that LIT is a key method to improve 100 m swimming performance and speeds in the GST phases through aerobic contribution and improved stroke kinematics in adolescent swimmers. LIT was observed to improve the IdC values, especially SI, in the SL and graded swim test. The more stable trend of the SI value in the first six stages of the GST was characterized as a reflection of the improvement of aerobic capacity on the stroke technique. In addition, the fact that SI did not change in the last two stages was thought to reflect the swimmers' increased energy requirement due to the metabolic changes in the exercise domain. Again, findings emphasize that IdC should be monitored at different speed ranges during progressive tests in adolescent swimmers in the follow-up of stroke coordination development. On the other hand, the fact that LIT did not change SR in both tests indicates that coaches should also include anaerobic power development in their programs through neuromuscular-based studies and all-out effort studies applied at short distances (such as 10\u0026ndash;25 m) with alactacid metabolism. In future studies, metabolic and kinematic evaluations of different interval training strategies in adolescent swimmers are needed.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAuthors\u0026apos; contribution\u003c/p\u003e\n\u003cp\u003eAuthor\u0026nbsp;Contributions:\u0026nbsp;E.D.,\u0026nbsp;E.U.\u0026nbsp;and\u0026nbsp;E.G.\u0026nbsp;designed\u0026nbsp;the\u0026nbsp;study.\u0026nbsp;E.D.\u0026nbsp;obtained\u0026nbsp;the\u0026nbsp;data.\u0026nbsp;E.U. and\u003c/p\u003e\n\u003cp\u003eE.D.\u0026nbsp;analyzed\u0026nbsp;the\u0026nbsp;data.\u0026nbsp;E.U.,\u0026nbsp;E.D.,\u0026nbsp;E.G.\u0026nbsp;interpreted\u0026nbsp;the\u0026nbsp;results\u0026nbsp;and\u0026nbsp;drafted\u0026nbsp;the\u0026nbsp;manuscript. E.U.,\u003c/p\u003e\n\u003cp\u003eE.G.\u0026nbsp;supervised\u0026nbsp;the\u0026nbsp;study.\u0026nbsp;All\u0026nbsp;authors\u0026nbsp;contributed\u0026nbsp;to the\u0026nbsp;review\u0026nbsp;and\u0026nbsp;revision\u0026nbsp;of the\u0026nbsp;manuscript and agree to be accountable for all aspects of the work, ensuring integrity and accuracy.\u0026nbsp;All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003eData\u0026nbsp;availability statement\u003c/p\u003e\n\u003cp\u003eThe data of this study were used only for scientific purposes and participant information was kept confidential. The findings of this study are supported by raw data, which the corresponding author is willing to share upon reasonable request. The sharing of data will be decided based on the principles of ethics and confidentiality, and may be given to editors or reviewers if asked for.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of AI Use:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGrammarly and ChatGPT4.0 were used by the authors during the preparation of this work to improve its readability and language. The authors then reviewed and edited the content as needed and took full responsibility for the publication\u0026apos;s content.\u003c/p\u003e\n\u003cp\u003eDeclaration\u0026nbsp;of\u0026nbsp;conflicting interests\u003c/p\u003e\n\u003cp\u003eThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe non-invasive research ethics committee of Dokuz Eylul University also approved the study, dated January 01, 2019, and numbered\u0026nbsp;2019/01-48.\u0026nbsp;The\u0026nbsp;study\u0026nbsp;progressed\u0026nbsp;throughout,\u0026nbsp;adhering\u0026nbsp;to\u0026nbsp;the\u0026nbsp;Helsinki Declaration.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThe author(s) received no financial support for the research, authorship, and/or publication of this article.\u003c/p\u003e\n\u003cp\u003ePractical\u0026nbsp;Application\u003c/p\u003e\n\u003cp\u003eIn adolescent swimmers, technical and aerobic power are dependent values that develop together. Increasing aerobic power makes the kinematics of arm movements more efficient as the swimming time increases. Their contribution is in the time domain and is mainly related to the efficiency of aerobic energy sources. We believe that the breaking points in SL during training sessions or competitions indicate the starting point of the transition from fatigue to exhaustion, at this point, energy expenditure shifts to anaerobic sources. Coaches\u0026apos; observations regarding these changes may be useful in determining performance thresholds. Maximizing aerobic capacity in adolescent swimmers due to growth and development is crucial for long- term \u0026nbsp;swimmer development.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eZacca, R. et al. DB,. Monitoring age- group swimmers over a training macrocycle: energetics, technique, and anthropometrics [Internet]. (2018). 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Living\u003c/em\u003e. \u003cb\u003e4\u003c/b\u003e, 799690. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3389/fspor.2022.799690\u003c/span\u003e\u003cspan address=\"10.3389/fspor.2022.799690\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2022).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 3 are available in the Supplementary Files section.\u003c/p\u003e"},{"header":"Graphics","content":"\u003cp\u003eGraphics 1 and 2 are available in the Supplementary Files section.\u003c/p\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":"Adolescent Swimmers, Interval Training, 100 Meter Freestyle Swimming Performance, Graded Swimming Protocol, Stroke Kinematics","lastPublishedDoi":"10.21203/rs.3.rs-6750664/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6750664/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study aimed to investigate the effects of 6-week long interval training (LIT) program on\u003c/p\u003e \u003cp\u003e100 meter (m) freestyle, graded swimming performance and stroke biomechanics. Nine swimmers (13.55\u0026thinsp;\u0026plusmn;\u0026thinsp;1.42 years) were included the LIT. This training period consisted of 4x300 m swims 3 times a week. Graded Swimming Protocol (GSP) and 100 m freestyle swimming performance were performed before and after the LIT period to evaluate the stroke kinematic and swimming performance changes. The paired sample-t test analysis determined in all parameters before and after the test. The result of GSP showed improvements in swimming velocity (p\u0026thinsp;=\u0026thinsp;0.001), stroke length (p\u0026thinsp;=\u0026thinsp;0.011), stroke index (p\u0026thinsp;=\u0026thinsp;0.001), index of coordination (p\u0026thinsp;=\u0026thinsp;0.013). Stroke rate (SR) values demonstrated decrease in certain stages and increase in others. In the 100 m test, the swimming speed (p\u0026thinsp;=\u0026thinsp;0.010), stroke length (SL) (p\u0026thinsp;=\u0026thinsp;0.028), stroke index (SI) (p\u0026thinsp;=\u0026thinsp;0.006) improved. There was a slightly decrease in SR, but not significant. This training method in adolescent swimmers can be used as a unique method for improving stroke kinematic parameters that support aerobic capacity-based swimming performance enhancement.\u003c/p\u003e","manuscriptTitle":"The Effect of Long Interval Training on Swimming Performance and Stroke Kinematics in Adolescent Swimmers","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-20 16:32:02","doi":"10.21203/rs.3.rs-6750664/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":"60841d81-c94d-4ebe-8dc7-a0778200457e","owner":[],"postedDate":"June 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":50258445,"name":"Biological sciences/Physiology"},{"id":50258446,"name":"Health sciences/Anatomy"}],"tags":[],"updatedAt":"2025-07-15T05:27:43+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-20 16:32:02","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6750664","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6750664","identity":"rs-6750664","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}