INTRODUCTION: The ability to generate high force levels in limited time (i.e., rate of torque development, RTD) is key factor of performance in sprint running. As an example, a world-class athlete generates horizontal force over 10 N/kg in less than 400ms during sprint start (1). While neural drive has been reported as the key determinant of early RTD (2), muscle-tendon interactions of the medial gastrocnemius (MG) seem to contribute to later phases of RTD (3). However, very little is known about RTD determinants regarding elite athletes. The aim of this study was to investigate elite athletes` ability to rapidly generate high force levels in relation to the contractile characteristics of plantar flexors. METHODS: 57 French elite athletes (32 track athletes, 22 rugby players, 3 bobsledders; 54% female; 1.75 ± 0.08 m; 70.5 ± 11.3 kg; including Olympic, World and European medallists) were tested. All participants completed 2-3 explosive force production trials "as fast and hard as possible" (3). Rate of torque development (RTD) was calculated over sequential windows (RTD 0-50ms, RTD 50-100ms, RTD 100-150ms and RTD 0-200ms). MG fascicle dynamics was assessed during the first 200ms using an ultrafast ultrasound scanner (sampling rate = 1000 Hz). MG fascicle shortening amplitude as well as mean and maximal fascicle shortening velocity were calculated. RESULTS: Rate of torque development at each sequential window was 437 ± 159 N.m/s [0-50ms], 1000 ± 323 N.m/s [50-100ms], 682 ± 223 N.m/s [100-150ms], 620 ± 165 N.m/s [0-200ms] (group mean ± SD). MG fascicles shortened throughout the first 200ms of contraction by 1.1 ± 0.4 cm, and maximal shortening velocity was -10.8 ± 3.7 cm/s and peaked at 50ms on average. CONCLUSION: This study brings novel insights about elite athletes` explosive force ability with exceptionally high rate of torque development, two-fold greater than those reported in healthy individuals using the same method (3). We also found that MG fascicle shortening velocity peaked on average around 50ms in elite athletes in comparison to around 100ms in healthy individuals. This clearly demonstrates the high explosiveness ability of elite athletes. Specifically, not only neural but also mechanical factors determine early RTD and thus sprint propulsion in elite athletes.
© Copyright 2022 27th Annual Congress of the European College of Sport Science (ECSS), Sevilla, 30. Aug - 2. Sep 2022. Veröffentlicht von Faculty of Sport Science - Universidad Pablo de Olavide. Alle Rechte vorbehalten.