The effect of TRX exercises on swimming performance and selected physical fitness in swimmers

YAĞMUR YILDIZ1, HÜSEYIN ÜNLÜ2

1Department of Sports and Health; 2Faculty of Sport Sciences - Aksaray University, Aksaray, Türkiye.

Summary. This study aimed to investigate the effects of 8 weeks of TRX exercises on balance, strength and swimming performances in swimmers. Twenty-eight prepubescent boy swimmers (age: 11.25 ± 1.37 years; height: 148 ± 0.34 cm; weight: 40.82 ± 8.3 kg) were randomly divided into two groups (TRX, n=14 and Control group CON, n=14). TRX group performed the TRX exercise program 3 days a week for 30-45 minutes in addition to swimming training, while the control group continued their swimming training. Plank, flamingo balance, vertical jump, medicine ball throwing performance, 50m and 100m freestyle swimming performances were measured before and after the exercise program. Data are presented as mean and standard deviation with 95% confidence interval and the significance level was adopted as p<0.05. TRX group significantly increased plank (ES:0.74), vertical jump (ES:1.05), medicine ball throwing (ES:1.34) and 50 m (ES:0.59) and 100 m (ES:1.10) swimming performances (p<0.05), while this change was not significant in the control group (p>0.05). Our results found that TRX exercise positively affected the athletic performance parameters of swimmers. Therefore, incorporating TRX exercises into the training programs of swimmers of this age group can improve their physical performance.

Key words. Swimming, TRX exercise, balance, strength, athletic performance.

L’effetto degli esercizi TRX sulle prestazioni natatorie e sulla forma fisica selezionata nei nuotatori

Riassunto. Questo studio ha avuto l’obiettivo di analizzare gli effetti di 8 settimane di esercizi TRX sull’equilibrio, la forza e la performance natatoria in nuotatori. Ventotto nuotatori prepuberi di sesso maschile (età: 11,25 ± 1,37 anni; altezza: 148 ± 0,34 cm; peso: 40,82 ± 8,3 kg) sono stati suddivisi casualmente in due gruppi: gruppo TRX (n = 14) e gruppo di controllo CON (n = 14). Il gruppo TRX ha svolto un programma di esercizi TRX per 30–45 minuti, 3 giorni a settimana, in aggiunta all’allenamento di nuoto; il gruppo di controllo ha proseguito solo l’allenamento natatorio. Prima e dopo il programma di esercizi sono stati misurati i seguenti parametri: plank, equilibrio su una gamba (test del fenicottero), salto verticale, lancio della palla medica, e le prestazioni nei 50 m e 100 m stile libero. I dati sono presentati come media e deviazione standard con intervallo di confidenza al 95%, e il livello di significatività è stato fissato a p < 0,05. Il gruppo TRX ha mostrato miglioramenti significativi nel test plank (ES: 0,74), salto verticale (ES: 1,05), lancio della palla medica (ES: 1,34) e nelle prestazioni sui 50 m (ES: 0,59) e 100 m (ES: 1,10) stile libero (p < 0,05), mentre il gruppo di controllo non ha mostrato cambiamenti significativi (p > 0,05). I nostri risultati indicano che l’esercizio TRX ha avuto un impatto positivo sui parametri di performance atletica dei giovani nuotatori. Pertanto, l’inclusione di esercizi TRX nei programmi di allenamento per nuotatori di questa fascia d’età può contribuire a migliorare la loro prestazione fisica.

Parole chiave. Nuoto, esercizio TRX, equilibrio, forza, performance atletica.

Introduction

In swimming, various conditioning training methods are employed to enhance the athletic performance of swimmers¹. The effectiveness of these training programs depends on the intensity and characteristics of the training sessions. When training methods are analyzed, two primary strategies emerge: in-water training and dryland training².
During dryland training, swimmers commonly engage in resistance training (RT), which includes a variety of modalities and equipment³. One such modality is TRX (Total Resistance eXercise), a contemporary form of RT that utilizes body weight and gravity to perform both single- and multi-joint exercises⁴. TRX exercises, performed using suspension straps, are considered a modern variant of resistance training. In younger age groups, suspension-based exercises appear to be more appropriate and safer⁵. TRX training has been shown to enhance various aspects of physical performance, including muscular strength and endurance⁶, as well as core stability encompassing the abdominal, trunk, back, and hip muscles. Furthermore, TRX exercises conducted under unstable conditions may be more effective than those performed under stable conditions⁷,⁸.

Body weight resistance exercises are considered to be a valuable exercise method in children because TRX exercise provides an opportunity to activate the main muscle groups without using any weight equipment. Therefore, TRX exercise offers the opportunity to exercise with body weight without using any additional weight to activate the main muscle groups⁹. TRX exercises can improve muscular strength and endurance and increase trunk stability. This not only affects performance improvement in swimmers but also helps to complete their turns and postural control. It also affects the maintenance of body flow and balance during the gliding phase¹⁰. Again, the suspended position realized by means of TRX equipment provides conditions similar to the suspended position in water¹¹. Therefore, it is thought that TRX exercise programs have an important place in swimming. However, it has been observed that there are significant gaps in the prescription and effectiveness of resistance exercise programs in improving swimming performance1,12,13. This study aimed to investigate the effects of TRX exercises on swimming performance and selected physical fitness parameters in swimmers. We hypothesized that swimmers who performed TRX exercises along with their swimming training can improve their athletic performance.

Methods

Participants

Twenty-eight prepubescent (age: 11.25 ± 1.37 years; height: 1.48 ± 0.34 cm; weight: 40.82 ± 8.3 kg, tanner stage of 2 and 3) swimmers voluntarily participated in the study. All participants (TRX, n=14 and Control, n=14) were male swimmers. The minimum number of participants needed was determined by G-Power analysis version 3.1.9.6 (Dusseldorf, Germany)14,15. According to the 2-way repeated measures ANOVA test for the measurements of 2 independent groups (Control and TRX) to be taken at 2 times (Pre-test - Post-test), the minimum number of participants (sample) was found to be 26 in total for 80% power, 0.05 error level two-sided hypothesis test (Effect size: 0.50)14. Before starting the research, the participants’ consent form was obtained by the children’s parents. This study was performed in accordance with the principles of the Declaration of Helsinki. The Ethics Committee of the University (Registration number: blinded for peer review) approved it.

Study Design

In this study, a pre-test and post-test experimental design model was used. Subjects were randomly divided into two groups (TRX, n=14 and Control, n=14) using a 2-block randomization method (Random Allocation Software). All participants followed the same swimming training program. The only difference between the groups was the inclusion of the TRX suspension training, which was added to the TRX group’s dry-land training session. The athletes performed plank, flamingo balance test, vertical jump test, medicine ball throwing tests and 50m/100m freestyle swimming tests in the pre and post-tests. Except for the exercise protocol applied throughout the study and the 50m and 100m freestyle swimming performances, all tests were performed in a room with a temperature of 20-24°C. The 50m and 100m freestyle swimming performances were conducted in the Olympic indoor swimming pool. The athletes were not provided with any ergogenic supplements throughout the study and were asked to follow their normal nutrition programs and not to disturb their normal sleep patterns. At least 2 hours before the start of the training, the athletes were asked to stop their food intake except water. At the same time, a 10-minute standardized warm-up (self-selected easy jogging, dynamic stretching) protocol was performed before the exercise program.

All training sessions throughout the study were performed on the same day of the week (Wednesday-Friday / 12.00-13.30) and at the same time (±1 hour). Before starting the exercise program, the experimental group underwent a familiarization session. The athletes participated in a total of 24 exercise sessions 3 times a week for 8 weeks. Progressive overload was achieved by increasing exercise intensity (TRX stability, vectorial and pendulum principles), sets, and reps. The number of repetitions was increased after the 2nd week and the number of sets after the 4th week, reaching a volume of 12 repetitions and 3 sets in the 7th and 8th weeks. In addition, the number of exercises was increased every 2 weeks. Pre-tests and post-tests were completed 48 hours before and after the exercise program. No side effects or injuries/injuries were observed during the training.

A total of 10 exercises, including TRX upper body, lower body, and core exercises were performed. Athletes were given 45 seconds of rest between sets and 2 minutes rest between each exercise. The training period lasted 30-45 minutes in total. The tempo of the exercise was monitored with the iOS-compatible Pro Metronome (Xanin Technology, Berlin, Germany) mobile application and the tempo of the exercise was completed in a total of 2 s, 1 s concentric and 1 s eccentric. The upper extremity exercises included the Biceps Curl, Chest Press, TRX Inverted Row, and Chest Fly, while the lower extremity exercises included the Hamstring Curl, TRX Squat Jump, Calf Rise, and Lateral Skater with Stick. Core exercises consisted of Knee Tuck, Bicycle Crunch exercises.

Procedures

Flamingo balance

The athletes were asked to balance on a 50 cm long, 5 cm high and 3 cm wide beam while standing on one leg, bending the free leg at the knee, keeping the foot close to the hip and balancing with the hands on the waist. The athletes were asked to stand in the specified position for 1 minute and the time was recorded with a Casio brand stopwatch. The stopwatch was stopped when the athlete lost his/her balance, when the unbalanced foot touched the ground and when any part of his/her body touched the ground, and the stopwatch was restarted after taking the starting position. The test continued for 1 minute and the number of moves made to stay balanced for 1 minute was recorded as the test result16.

Vertical jump

A Fitjump (vertical jump performance test device; Sporsis, Afyonkarahisar, Türkiye) was used to assess Vertical jump height17. Participants completed two vertical jump trials after performing the warm-up. They were encouraged to jump as high as possible for each jump18. Participants were instructed to move quickly and continuously in one constant movement from a standing posture (without arm swings) to a self-selected depth while performing the downward phase of the vertical jump. Each participant completed two trials (with a one-minute rest between trials), and the maximum CMJ height (cm) was recorded for analysis17.

Plank

The athletes were asked to lie prone, with their forearms and elbows bilaterally shoulder-width apart and positioned on their toes. In this position, the athletes were asked to lift the pelvis slightly so that the neck, shoulders, back, hips and legs form a straight line parallel to the ground and to maintain a stable posture. In case the athletes got tired and quit and/or changed their posture, the chronemeter was stopped and the elapsed time was recorded in seconds for analysis19.

Medicine ball throwing

The medicine ball throwing test was used to measure the upper extremity strength of the athletes. For this test, athletes were given 2 trials with a 2-minute rest break. The best throwing degree was recorded by measuring the distance between the point where the medicine ball fell and the starting point in meters as a result of the athletes throwing the 2-kilogram medicine ball forward with two arms from behind the head while sitting on their knees20.

50m/100m freestyle swimming test

The swimming test was conducted in the 50 m long olympic indoor swimming Pool. The athletes were asked to swim 50 m and 100 m freestyle at maximum effort. The test was performed from inside the pool with the command “Ready! Get out!” command from inside the pool and the test was started from the moment the athlete pushed the wall of the pool with his/her feet and ended when the athlete completed the 50 m/100 m distance and touched the wall with his/her hands. The test time was determined with a Casio handheld stopwatch and the results were recorded in seconds. The tests were performed with a minimum interval of 48 hours21.

Statistical analyses

All data were presented as mean ± standard deviation with 95% confidence intervals. Two-way repeated measures ANOVA (2x2) model was used to test the group, time and group-time interaction terms. The significance of pre-test-post-test changes in pairwise comparisons was also tested using COMPARE (Time) ADJ (Bonferroni) SPSS syntax. In the Partial square (pη2) value expressing the effect size, 0.01-0.06 was considered as low effect size, 0.06-0.14 as medium effect size and 0.14 and above as high effect size. Cohens’ d effect size was used to express the change between pretest and posttest. Effect size was interpreted as insignificant if it was less than 0.2, small between 0.2-0.5, medium between 0.5-0.8 and large more than 0.8. The pre-test-post-test percentage change calculations of the groups were calculated with the formula [(post-test - pre-test) / pre-test] x 100 [18, 19]. The level of significance was set at p < 0.05. Statistical tests were performed using SPSS v 29.0.

Results

Descriptive statistics of the swimmers are presented in table 1.




There were no differences between the control and the TRX groups (p>0.05).

There was a notable difference in plank performance between groups [F (1, 26) = 11.085, p = 0.003, pη2=0.299], favoring the TRX group. The TRX group significantly improved their plank performance from pre- to post-training (p<0.01; ES:1.17 large effect size), while this change was not significant in the control group (p=0.848). Additionally, the TRX group showed an increase in their plank performance from pre- to post-training (Δ 3.5%), whereas the control group experienced a decline in performance (Δ 2.5%).

There was a significant difference in flamingo balance test performance between groups [F (1, 26) = 9.405, p = 0.005, pη2=0.266] in favor of the TRX group. TRX group significantly increased their flamingo balance test performance (p=0.015; ES:0.74 large effect size), while this change was not significant in the control group (p=0.057). In addition, TRX group increased their flamingo balance test performance pre- to post-training (Δ 36.6%), whereas the control group increased their performance (Δ 24.5%) (figure 1, table 2).







There were no significant differences in vertical jump performance between the groups [F (1, 26) = 1.890, p = 0.181, pη2=0.068]. The TRX group significantly increased their vertical jump performance from pre- to post-training (p<0.01; ES=1.05, large effect size), while the control group showed a decrease in jump performance (p=0.451). Additionally, the TRX group improved their plank performance from pre- to post-training (Δ 9.20%), whereas the control group experienced a decrease in performance (Δ 4.91%).

There was a significant difference in medicine ball throwing performance between groups [F (1, 26) = 24.813, p = <0.01, pη2=0.488] in favor of the TRX group. TRX group significantly increased their flamingo balance test performance (p<0.01; ES=1.34 large effect size), while this change was not significant in the control group (p=0.078). In addition, TRX group increased their medicine ball throwing performance pre- to post-training (Δ 13.56%), whereas the control group increased their performance (Δ 4.25%) (figure 2, table 3).







There was a significant difference in 50 m freestyle performance between the groups [F (1, 26) = 5.234, p = 0.031, pη2=0.168], favoring the TRX group. The TRX group significantly improved their 50m freestyle performance from pre- to post-training (p<0.05; ES:0.59, large effect size), while this change was not significant for the control group (p>0.05). Additionally, the TRX group increased their plank performance from pre- to post-training (Δ 3.5%), whereas the control group saw a decrease in performance (Δ 0.2%).

There was a significant difference in 100 m freestyle performance between groups [F (1, 26) = 5.769, p = 0.024, pη2=0.182] in favor of the TRX group. TRX group significantly improved their 100m freestyle performance pre- to post-training (p<0.05; ES:1.10 large effect size), while this change was not significant in the control group (p>0.05). In addition, TRX group increased their plank performance pre- to post-training (Δ 3.8%), whereas the control group decreased their performance (Δ 0.8%) (figure 3, table 4).







Discussion

This study aimed to investigate the effects of 8 weeks of TRX exercises on balance, strength and swimming performances in prepubescent boy swimmers. The main findings of this research are that TRX exercise can improve prepubescent boys’ swimmers’ strength balance and 50 m and 100 m freestyle swimming performances. It is known that TRX exercises have a positive effect on the muscles of the core region, which includes the abdominal, trunk, waist, hip muscles and provides body stability7. It was concluded that the plank performance of the group performing TRX exercises had better performance scores compared to the control group. Similar to our findings, Tinto et al. concluded that integrating TRX exercise into dry land training supports core strength and core stability16. In another study, it was shown that TRX exercises performed for 8 weeks provided core muscle activation and consequently supported strength in sedentary youth17. According to these results, it can be inferred that TRX exercises can be effective in different groups such as athletes and sedentary individuals.

Moreover, Byrne et al. examined the effects of TRX exercises on muscle activation and found a significant increase in the activation of rectus abdominis, external oblique, rectus femoris and serratus anterior muscles18. In another study conducted on police college students, the authors investigated the effects of TRX exercises and resistance exercises for 12 weeks on abdominal muscle strength and isometric abdominal muscle endurance. The authors found that the group performing TRX exercise significantly improved their abdominal muscle strength and longissimus muscle strength in the erector spinae muscle group19. It is also known that TRX exercises increase upper body20, core and lower extremity muscle activation21. In our study, it was observed that plank performance improved by 3.5% in the TRX group, while it decreased by 2.5% in the control group. It is thought that the application of exercises (knee tuck, bicycle crunch) in TRX training program to strengthen the muscles of the core muscles may be effective in the development of plank performance.

When the Flamingo balance test results were analyzed, the increase in the TRX group was found to be significant (p=0.015; EB:0.74), while the change in the control group was not significant (p=0.057). In a study conducted to evaluate the effect of TRX system on female students and their static balance, the participants performed traditional resistance exercises and TRX exercises for 45/60 minutes 2 days a week for 10 weeks. As a result, it was determined that the TRX exercise group experienced improvement in left and right leg static balance scores22. Curiţianu and Cătănescu found that 6-week TRX exercises performed 3 times a week resulted in a significant increase in endurance, stability and balance in upper and lower extremities in female skiers23. In our study, while the performance of the TRX group improved by 36.6% in flamingo balance performance, 24.5% improvement was found in the flamingo balance performance of the control group. Based on these data, it can be said that TRX exercises can be more effective on performance parameters in different sports branches such as swimming and skiing.

Unlike the findings of our study, Boros-Balınt et al. examined whether a 3-week TRX exercise program was sufficient to improve static balance in young basketball players. As a result, it was determined that the 3-week TRX exercise program was insufficient for changes in the static balance of young basketball players24. In parallel with this study, Blasco et al. examined the effects of a 9-session TRX exercise program on dynamic and static balance, stability and functional performance, but the authors concluded that a 9-session TRX exercise program did not significantly affect the ability to maintain static position. As a result, it can be said that TRX exercises are insufficient to provide physical and physiological adaptations in short periods such as 3 weeks. Based on this, it can be concluded that TRX exercises improve balance performance in swimmers25. However, it can be deduced that especially training duration and frequency have a critical importance on balance perameters.

In our study, the pre-test-post-test change in the vertical jump performance of swimmers in the TRX group was significant (p<0.01; EB=1.05), while this change was not significant in the control group (p=0.451). Vertical jump performance increased by 9.20% in the TRX group and decreased by 4.91% in the control group. In parallel with our findings, as a result of land exercises with TRX exercise band for 8 weeks in swimmers, it was determined that lower extremity strength improved more in percentage and statistically compared to the group performing resistance exercise with body weights and the control group26. Therefore, it can be concluded that incorporating of TRX exercises in the land training programs in swimmers may be effective on lower extremity strength.

It has been shown that TRX exercises performed for 6 to 8 weeks positively affect jump performance in different sports. For example, Demirar et al. found that basketball training combined with an 8-week TRX training program significantly increased vertical jump performance in basketball players27. Moreover, research showed that TRX exercises were effective on jump performance in different populations such as university students who do not do regular sports28, young sedentary individuals17, police college students19.

It was reported that 8-week TRX exercises performed with 21 male swimmers aged 13 years had a better effect on the strengthening of the core and upper extremity compared to the control group and the groups performing their own body weight + swimming training26. The findings of this study are similar to the results of our study. In parallel with our findings, Laurent et al. examined the effectiveness of TRX exercise program applied twice a week for 6 weeks on muscle and skill-related fitness and functional movement. In a study with 28 children (9.3 ± 1.5 years), they found a 43.6% improvement in upper body muscular endurance (Modified Pull-Up performance) in the experimental group with TRX exercises29. As a result, when the literature was examined, it was seen that TRX exercises for upper extremity strength development applied for 6-8 weeks were effective in upper extremity strength parameters in athletes30,31, adolescents and pre-adolescent children5.

In our study, it was determined that the 50 m and 100 m freestyle swimming performances of the group performing TRX exercises were positively affected. Similarly, Eskiyecek et al. concluded in their study that upper extremity TRX exercises applied for 8 weeks in swimmers aged 10-12 years positively affected 50 m stroke count, 25 m and 50 m freestyle swimming degrees12. Şenol and Gülmez reported that resistance exercises using a TRX exercise band improved 50m freestyle swimming performance in male swimmers26. Yapıcı et al. examined the effect of 6-week resistance and land exercises on lower extremity isokinetic strength performance and found that there were significant differences in the 50 m, 75 m and 100 m free swimming degrees of 13-16 age group swimmers, which supported our findings32. Similarly, Grant and Kavaliauskas examined the effect of resistance exercises applied on land for 7 weeks on swimming performance, physiological variables and anthropometric variables in elite swimmers, and as a result, they found that there was a 1.12% increase in 100m freestyle swimming performance of swimmers33. It can be concluded that exercises performed under unstable conditions have a positive effect on strength34 and other physical parameters.35 This study had some limitations like other studies. For instance, the duration of the training program was short due to training schedule restrictions; moreover, the dietary intake and nutrition status of the subjects were not tracked. Lastly, swimming performance was not recorded by the electronic time system. Future studies can be conducted on different age groups and athletes.

Conclusions

To the best of our knowledge, no previous study has simultaneously examined the effects of TRX exercises on balance, strength, and 50 m/100 m freestyle swimming performance in male swimmers aged 9-13 years. This comprehensive evaluation highlights the study’s originality, as it is the first to implement such a program within this specific age and gender group. The findings provide evidence supporting the integration of TRX suspension training into dryland exercise programs to enhance performance in male swimmers. It can be concluded that TRX exercises may serve as an applicable method for improving the swimming performance levels of youth athletes. Furthermore, based on our findings, future research may focus on investigating the performance effects of TRX exercise programs in different swimming strokes (Butterfly, Breaststroke, Backstroke). It is important to note that this study included only male swimmers. Therefore, implementing TRX exercises in female swimmers and evaluating their performance responses could contribute to the existing body of literature. Additionally, TRX exercises may be applied across different sports disciplines, age groups, durations, and frequencies to assess their outcomes. Lastly, the TRX exercise program in this study was applied exclusively to healthy athletes. Hence, applying TRX training to individuals with sports-related injuries could offer insights into its potential rehabilitative effects.

Conflicts of interest. The authors declare that there is no conflict of interest.

Acknowledgments. This study is derived from the first author’s PhD dissertation and supported by the Scientific Research Project Coordinatorship/BAP of Aksaray University (Project number: 2023-012).

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