TY - JOUR A1 - Sammoud, Senda A1 - Nevill, Alan Michael A1 - Negra, Yassine A1 - Bouguezzi, Raja A1 - Chaabene, Helmi A1 - Hachana, Younes T1 - 100-m Breaststroke Swimming Performance in Youth Swimmers BT - the predictive value of anthropometrics JF - Pediatric exercise science N2 - 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. KW - allometric model KW - maturity KW - limb lengths KW - girths and breadths Y1 - 2018 U6 - https://doi.org/10.1123/pes.2017-0220 SN - 0899-8493 SN - 1543-2920 VL - 30 IS - 3 SP - 393 EP - 401 PB - Human Kinetics Publ. CY - Champaign ER - TY - JOUR A1 - Chaabene, Helmi A1 - Negra, Yassine A1 - Capranica, Laura A1 - Prieske, Olaf A1 - Granacher, Urs T1 - A Needs Analysis of Karate Kumite With Recommendations for Performance Testing and Training JF - Strength and conditioning journal N2 - An effective training program needs to be customized to the specific demands of the redpective sport. Therefore, it is important to conduct a needs analysis to gain information on the unique characteristics of the sport. The objectives of thes review were (A) to conduct a systematic needs analysis of karate kumite and (B) to provide practical recommendations for sport-specific performance testing and training of karate kumite athletes. KW - sport profile KW - striking combat sports KW - strength KW - power KW - energetic systems KW - injury KW - assessment Y1 - 2019 U6 - https://doi.org/10.1519/SSC.0000000000000445 SN - 1524-1602 SN - 1533-4295 VL - 41 IS - 3 SP - 35 EP - 46 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - GEN A1 - Hammami, Raouf A1 - Chaabene, Helmi A1 - Kharrat, Fatma A1 - Werfelli, Hanen A1 - Duncan, Michael A1 - Rebai, Haithem A1 - Granacher, Urs T1 - Acute effects of different balance exercise types on selected measures of physical fitness in youth female volleyball players T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Background Earlier studies have shown that balance training (BT) has the potential to induce performance enhancements in selected components of physical fitness (i.e., balance, muscle strength, power, speed). While there is ample evidence on the long-term effects of BT on components of physical fitness in youth, less is known on the short-term or acute effects of single BT sessions on selected measures of physical fitness. Objective To examine the acute effects of different balance exercise types on balance, change-of-direction (CoD) speed, and jump performance in youth female volleyball players. Methods Eleven female players aged 14 years participated in this study. Three types of balance exercises (i.e., anterior, posterolateral, rotational type) were conducted in randomized order. For each exercise, 3 sets including 5 repetitions were performed. Before and after the performance of the balance exercises, participants were tested for their static balance (center of pressure surface area [CoP SA] and velocity [CoP V]) on foam and firm surfaces, CoD speed (T-Half test), and vertical jump height (countermovement jump [CMJ] height). A 3 (condition: anterior, mediolateral, rotational balance exercise type) × 2 (time: pre, post) analysis of variance was computed with repeated measures on time. Results Findings showed no significant condition × time interactions for all outcome measures (p > 0.05). However, there were small main effects of time for CoP SA on firm and foam surfaces (both d = 0.38; all p < 0.05) with no effect for CoP V on both surface conditions (p > 0.05). For CoD speed, findings showed a large main effect of time (d = 0.91; p < 0.001). However, for CMJ height, no main effect of time was observed (p > 0.05). Conclusions Overall, our results indicated small-to-large changes in balance and CoD speed performances but not in CMJ height in youth female volleyball players, regardless of the balance exercise type. Accordingly, it is recommended to regularly integrate balance exercises before the performance of sport-specific training to optimize performance development in youth female volleyball players. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 713 KW - Postural stability KW - Conditioning activity KW - Short‐term effect KW - Team sports KW - Youth Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-517477 SN - 1866-8364 IS - 713 ER - TY - JOUR A1 - Hammami, Raouf A1 - Chaabene, Helmi A1 - Kharrat, Fatma A1 - Werfelli, Hanen A1 - Duncan, Michael A1 - Rebai, Haithem A1 - Granacher, Urs T1 - Acute effects of different balance exercise types on selected measures of physical fitness in youth female volleyball players JF - BMC Sports Science, Medicine and Rehabilitation N2 - Background Earlier studies have shown that balance training (BT) has the potential to induce performance enhancements in selected components of physical fitness (i.e., balance, muscle strength, power, speed). While there is ample evidence on the long-term effects of BT on components of physical fitness in youth, less is known on the short-term or acute effects of single BT sessions on selected measures of physical fitness. Objective To examine the acute effects of different balance exercise types on balance, change-of-direction (CoD) speed, and jump performance in youth female volleyball players. Methods Eleven female players aged 14 years participated in this study. Three types of balance exercises (i.e., anterior, posterolateral, rotational type) were conducted in randomized order. For each exercise, 3 sets including 5 repetitions were performed. Before and after the performance of the balance exercises, participants were tested for their static balance (center of pressure surface area [CoP SA] and velocity [CoP V]) on foam and firm surfaces, CoD speed (T-Half test), and vertical jump height (countermovement jump [CMJ] height). A 3 (condition: anterior, mediolateral, rotational balance exercise type) × 2 (time: pre, post) analysis of variance was computed with repeated measures on time. Results Findings showed no significant condition × time interactions for all outcome measures (p > 0.05). However, there were small main effects of time for CoP SA on firm and foam surfaces (both d = 0.38; all p < 0.05) with no effect for CoP V on both surface conditions (p > 0.05). For CoD speed, findings showed a large main effect of time (d = 0.91; p < 0.001). However, for CMJ height, no main effect of time was observed (p > 0.05). Conclusions Overall, our results indicated small-to-large changes in balance and CoD speed performances but not in CMJ height in youth female volleyball players, regardless of the balance exercise type. Accordingly, it is recommended to regularly integrate balance exercises before the performance of sport-specific training to optimize performance development in youth female volleyball players. KW - Postural stability KW - Conditioning activity KW - Short‐term effect KW - Team sports KW - Youth Y1 - 2021 U6 - https://doi.org/10.1186/s13102-021-00249-5 SN - 1758-2555 VL - 13 PB - BioMed Central CY - London ER - TY - GEN A1 - Chaabene, Helmi A1 - Behm, David George A1 - Negra, Yassine A1 - Granacher, Urs T1 - Acute Effects of Static Stretching on Muscle Strength and Power BT - An Attempt to Clarify Previous Caveats T2 - Postprints der Universität Potsdam Humanwissenschaftliche Reihe N2 - The effects of static stretching (StS) on subsequent strength and power activities has been one of the most debated topics in sport science literature over the past decades. The aim of this review is (1) to summarize previous and current findings on the acute effects of StS on muscle strength and power performances; (2) to update readers’ knowledge related to previous caveats; and (3) to discuss the underlying physiological mechanisms of short-duration StS when performed as single-mode treatment or when integrated into a full warm-up routine. Over the last two decades, StS has been considered harmful to subsequent strength and power performances. Accordingly, it has been recommended not to apply StS before strength- and power-related activities. More recent evidence suggests that when performed as a single-mode treatment or when integrated within a full warm-up routine including aerobic activity, dynamic-stretching, and sport-specific activities, short-duration StS (≤60 s per muscle group) trivially impairs subsequent strength and power activities (∆1–2%). Yet, longer StS durations (>60 s per muscle group) appear to induce substantial and practically relevant declines in strength and power performances (∆4.0–7.5%). Moreover, recent evidence suggests that when included in a full warm-up routine, short-duration StS may even contribute to lower the risk of sustaining musculotendinous injuries especially with high-intensity activities (e.g., sprint running and change of direction speed). It seems that during short-duration StS, neuromuscular activation and musculotendinous stiffness appear not to be affected compared with long-duration StS. Among other factors, this could be due to an elevated muscle temperature induced by a dynamic warm-up program. More specifically, elevated muscle temperature leads to increased muscle fiber conduction-velocity and improved binding of contractile proteins (actin, myosin). Therefore, our previous understanding of harmful StS effects on subsequent strength and power activities has to be updated. In fact, short-duration StS should be included as an important warm-up component before the uptake of recreational sports activities due to its potential positive effect on flexibility and musculotendinous injury prevention. However, in high-performance athletes, short-duration StS has to be applied with caution due to its negligible but still prevalent negative effects on subsequent strength and power performances, which could have an impact on performance during competition. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 585 KW - passive stretching KW - physical fitness KW - physiology KW - range of motion KW - injury Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-440036 SN - 1866-8364 IS - 585 ER - TY - JOUR A1 - Chaabene, Helmi A1 - Behm, David George A1 - Negra, Yassine A1 - Granacher, Urs T1 - Acute Effects of Static Stretching on Muscle Strength and Power BT - An Attempt to Clarify Previous Caveats JF - Frontiers in Physiology N2 - The effects of static stretching (StS) on subsequent strength and power activities has been one of the most debated topics in sport science literature over the past decades. The aim of this review is (1) to summarize previous and current findings on the acute effects of StS on muscle strength and power performances; (2) to update readers’ knowledge related to previous caveats; and (3) to discuss the underlying physiological mechanisms of short-duration StS when performed as single-mode treatment or when integrated into a full warm-up routine. Over the last two decades, StS has been considered harmful to subsequent strength and power performances. Accordingly, it has been recommended not to apply StS before strength- and power-related activities. More recent evidence suggests that when performed as a single-mode treatment or when integrated within a full warm-up routine including aerobic activity, dynamic-stretching, and sport-specific activities, short-duration StS (≤60 s per muscle group) trivially impairs subsequent strength and power activities (∆1–2%). Yet, longer StS durations (>60 s per muscle group) appear to induce substantial and practically relevant declines in strength and power performances (∆4.0–7.5%). Moreover, recent evidence suggests that when included in a full warm-up routine, short-duration StS may even contribute to lower the risk of sustaining musculotendinous injuries especially with high-intensity activities (e.g., sprint running and change of direction speed). It seems that during short-duration StS, neuromuscular activation and musculotendinous stiffness appear not to be affected compared with long-duration StS. Among other factors, this could be due to an elevated muscle temperature induced by a dynamic warm-up program. More specifically, elevated muscle temperature leads to increased muscle fiber conduction-velocity and improved binding of contractile proteins (actin, myosin). Therefore, our previous understanding of harmful StS effects on subsequent strength and power activities has to be updated. In fact, short-duration StS should be included as an important warm-up component before the uptake of recreational sports activities due to its potential positive effect on flexibility and musculotendinous injury prevention. However, in high-performance athletes, short-duration StS has to be applied with caution due to its negligible but still prevalent negative effects on subsequent strength and power performances, which could have an impact on performance during competition. KW - passive stretching KW - physical fitness KW - physiology KW - range of motion KW - injury Y1 - 2019 U6 - https://doi.org/10.3389/fphys.2019.01468 SN - 1664-042X VL - 10 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Prieske, Olaf A1 - Chaabene, Helmi A1 - Moran, Jason A1 - Saeterbakken, Atle Hole T1 - Adaptations to Advanced Resistance Training Strategies in Youth and Adult Athletes JF - Frontiers in physiology / Frontiers Research Foundation KW - strength training KW - sportsmen KW - mechanisms KW - chronic effects KW - acute effects KW - applied physiology Y1 - 2022 U6 - https://doi.org/10.3389/fphys.2022.888118 SN - 1664-042X VL - 13 PB - Frontiers Media CY - Lausanne ER - TY - GEN A1 - Nevill, Alan M. A1 - Negra, Yassine A1 - Myers, Tony D. A1 - Duncan, Michael J. A1 - Chaabene, Helmi A1 - Granacher, Urs T1 - Are Early or Late Maturers Likely to Be Fitter in the General Population? T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - The present study aims to identify the optimal body-size/shape and maturity characteristics associated with superior fitness test performances having controlled for body-size, sex, and chronological-age differences. The sample consisted of 597 Tunisian children (396 boys and 201 girls) aged 8 to 15 years. Three sprint speeds recorded at 10, 20 and 30 m; two vertical and two horizontal jump tests; a change-of-direction and a handgrip-strength tests, were assessed during physical-education classes. Allometric modelling was used to identify the benefit of being an early or late maturer. Findings showed that being tall and light is the ideal shape to be successful at most physical fitness tests, but the height-to-weight “shape” ratio seems to be test-dependent. Having controlled for body-size/shape, sex, and chronological age, the model identified maturity-offset as an additional predictor. Boys who go earlier/younger through peak-height-velocity (PHV) outperform those who go at a later/older age. However, most of the girls’ physical-fitness tests peaked at the age at PHV and decline thereafter. Girls whose age at PHV was near the middle of the age range would appear to have an advantage compared to early or late maturers. These findings have important implications for talent scouts and coaches wishing to recruit children into their sports/athletic clubs. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 695 KW - youth KW - fitness tests KW - allometry KW - body shape KW - biological age Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-489928 SN - 1866-8364 IS - 695 ER - TY - JOUR A1 - Nevill, Alan M. A1 - Negra, Yassine A1 - Myers, Tony D. A1 - Duncan, Michael J. A1 - Chaabene, Helmi A1 - Granacher, Urs T1 - Are Early or Late Maturers Likely to Be Fitter in the General Population? JF - International Journal of Environmental Research and Public Health N2 - The present study aims to identify the optimal body-size/shape and maturity characteristics associated with superior fitness test performances having controlled for body-size, sex, and chronological-age differences. The sample consisted of 597 Tunisian children (396 boys and 201 girls) aged 8 to 15 years. Three sprint speeds recorded at 10, 20 and 30 m; two vertical and two horizontal jump tests; a change-of-direction and a handgrip-strength tests, were assessed during physical-education classes. Allometric modelling was used to identify the benefit of being an early or late maturer. Findings showed that being tall and light is the ideal shape to be successful at most physical fitness tests, but the height-to-weight “shape” ratio seems to be test-dependent. Having controlled for body-size/shape, sex, and chronological age, the model identified maturity-offset as an additional predictor. Boys who go earlier/younger through peak-height-velocity (PHV) outperform those who go at a later/older age. However, most of the girls’ physical-fitness tests peaked at the age at PHV and decline thereafter. Girls whose age at PHV was near the middle of the age range would appear to have an advantage compared to early or late maturers. These findings have important implications for talent scouts and coaches wishing to recruit children into their sports/athletic clubs. KW - youth KW - fitness tests KW - allometry KW - body shape KW - biological age Y1 - 2021 U6 - https://doi.org/10.3390/ijerph18020497 SN - 1660-4601 VL - 18 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - El-Ashker, Said A1 - Chaabene, Helmi A1 - Negra, Yassine A1 - Prieske, Olaf A1 - Granacher, Urs T1 - Cardio-Respiratory Endurance Responses Following a Simulated 3 x 3 Minutes Amateur Boxing Contest in Elite Level Boxers JF - Sports N2 - This study aimed at examining physiological responses (i.e., oxygen uptake [VO2] and heart rate [HR]) to a semi-contact 3 x 3-min format, amateur boxing combat simulation in elite level male boxers. Eleven boxers aged 21.4 +/- 2.1 years (body height 173.4 +/- 3.7, body mass 74.9 +/- 8.6 kg, body fat 12.1 +/- 1.9, training experience 5.7 +/- 1.3 years) volunteered to participate in this study. They performed a maximal graded aerobic test on a motor-driven treadmill to determine maximum oxygen uptake (VO2max), oxygen uptake (VO2AT) and heart rate (HRAT) at the anaerobic threshold, and maximal heart rate (HRmax). Additionally, VO2 and peak HR (HRpeak) were recorded following each boxing round. Results showed no significant differences between VO2max values derived from the treadmill running test and VO2 outcomes of the simulated boxing contest (p > 0.05, d = 0.02 to 0.39). However, HRmax and HRpeak recorded from the treadmill running test and the simulated amateur boxing contest, respectively, displayed significant differences regardless of the boxing round (p < 0.01, d = 1.60 to 3.00). In terms of VO2 outcomes during the simulated contest, no significant between-round differences were observed (p = 0.19, d = 0.17 to 0.73). Irrespective of the boxing round, the recorded VO2 was >90% of the VO2max. Likewise, HRpeak observed across the three boxing rounds were >= 90% of the HRmax. In summary, the simulated 3 x 3-min amateur boxing contest is highly demanding from a physiological standpoint. Thus, coaches are advised to systematically monitor internal training load for instance through rating of perceived exertion to optimize training-related adaptations and to prevent boxers from overreaching and/or overtraining. KW - aerobic metabolism KW - physiological strain KW - striking combat sports KW - elite athletes Y1 - 2018 U6 - https://doi.org/10.3390/sports6040119 SN - 2075-4663 VL - 6 IS - 4 PB - MDPI CY - Basel ER -