This study aimed to estimate the optimal body size, limb segment length, and girth or breadth ratios of 100-m breaststroke performance in youth swimmers. In total, 59 swimmers [male: n = 39, age = 11.5 (1.3) y; female: n = 20, age = 12.0 (1.0) y] participated in this study. To identify size/shape characteristics associated with 100-m breaststroke swimming performance, we computed a multiplicative allometric log-linear regression model, which was refined using backward elimination. Results showed that the 100-m breaststroke performance revealed a significant negative association with fat mass and a significant positive association with the segment length ratio (arm ratio = hand length/forearm length) and limb girth ratio (girth ratio = forearm girth/wrist girth). In addition, leg length, biacromial breadth, and biiliocristal breadth revealed significant positive associations with the 100-m breaststroke performance. However, height and body mass did not contribute to the model, suggesting that the advantage of longer levers was limb-specific rather than a general whole-body advantage. In fact, it is only by adopting multiplicative allometric models that the previously mentioned ratios could have been derived. These results highlighted the importance of considering anthropometric characteristics of youth breaststroke swimmers for talent identification and/or athlete monitoring purposes. In addition, these findings may assist orienting swimmers to the appropriate stroke based on their anthropometric characteristics.
Senda Sammoud, Alan Michael Nevill, Yassine Negra, Raja Bouguezzi, Helmi Chaabene and Younés Hachana
Helmi Chaabene, Yassine Negra, Jason Moran, Olaf Prieske, Senda Sammoud, Rodrigo Ramirez-Campillo and Urs Granacher
This study examined the effects of an 8-week Nordic-hamstring exercise (NHE) training on components of physical performance in young female handball players.
Participants were allocated to an experimental (EG; n=10; age: 15.9 ± 0.2 years) and a control group (CG; n=9; age: 15.9 ± 0.3 years). The EG performed NHE (2-3 sessions/week) in replacement of some handball-specific drills whereas the CG followed regular handball training. Pre- and post-training, tests were carried-out for the assessment of sprint speed (5 m, 10 m, 20 m), jump performance (countermovement jump [CMJ] height), change-of-direction (CoD [T-test]), and repeated-sprint-ability (RSA total-time [RSAtotal], RSA best-time [RSAbest], RSA fatigue-index [RSAFI]). Data were analyzed using magnitude-based inferences.
Within-group analyses for the EG showed moderate performance improvements for 5 m, 10 m, 20 m (effect-size [ES] = 0.68-0.82), T-test (ES=0.74), and CMJ (ES=0.85). Trivial-to-small improvements were observed for RSA (ES=-0.06-0.35). For the CG, within-group outcomes showed performance decrements with moderate (T-test [ES=0.71]), small (5 m [ES=0.46], and RSAbest [ES=0.20]), and trivial magnitude (10 m [ES=0.10], 20 m [ES=0.16] and RSAtotal [ES=0.00]). Further, trivial-to-small performance improvements were found for CMJ (ES=0.10) and RSAFI (ES=0.5). Between-group analyses revealed small-to-large effects in favor of EG for 5 m (ES=1.07), 10 m (ES=0.66), 20 m (ES=0.53), T-test (ES=1.38), and RSA (ES=0.68 to 0.78). A trivial between-group difference was demonstrated for CMJ (ES=-0.01).
The NHE training intervention, in replacement of some handball-specific drills, was more effective than regular handball training in improving physical performance (i.e., linear sprint-time, jumping, CoD, and RSA) in young female handball players.
Yassine Negra, Helmi Chaabene, Senda Sammoud, Olaf Prieske, Jason Moran, Rodrigo Ramirez-Campillo, Ali Nejmaoui and Urs Granacher
Purpose: To examine the effects of loaded (LPJT) versus unloaded plyometric jump training (UPJT) programs on measures of muscle power, speed, change of direction (CoD), and kicking-distance performance in prepubertal male soccer players. Methods: Participants (N = 29) were randomly assigned to a LPJT group (n = 13; age = 13.0 [0.7] y) using weighted vests or UPJT group (n = 16; age = 13.0 [0.5] y) using body mass only. Before and after the intervention, tests for the assessment of proxies of muscle power (ie, countermovement jump, standing long jump); speed (ie, 5-, 10-, and 20-m sprint); CoD (ie, Illinois CoD test, modified 505 agility test); and kicking-distance were conducted. Data were analyzed using magnitude-based inferences. Results: Within-group analyses for the LPJT group showed large and very large improvements for 10-m sprint time (effect size [ES] = 2.00) and modified 505 CoD (ES = 2.83) tests, respectively. For the same group, moderate improvements were observed for the Illinois CoD test (ES = 0.61), 5- and 20-m sprint time test (ES = 1.00 for both the tests), countermovement jump test (ES = 1.00), and the maximal kicking-distance test (ES = 0.90). Small enhancements in the standing long jump test (ES = 0.50) were apparent. Regarding the UPJT group, small improvements were observed for all tests (ES = 0.33–0.57), except 5- and 10-m sprint time (ES = 1.00 and 0.63, respectively). Between-group analyses favored the LPJT group for the modified 505 CoD (ES = 0.61), standing long jump (ES = 0.50), and maximal kicking-distance tests (ES = 0.57), but not for the 5-m sprint time test (ES = 1.00). Only trivial between-group differences were shown for the remaining tests (ES = 0.00–0.09). Conclusion: Overall, LPJT appears to be more effective than UPJT in improving measures of muscle power, speed, CoD, and kicking-distance performance in prepubertal male soccer players.