Sled towing: the optimal overload for peak power production

Purpose: The effects of different loads on kinematic and kinetic variables during sled towing were investigated with the aim to identify the optimal overload for this specific sprint training. Methods: Thirteen male sprinters (100-m personal best: 10.91 ± 0.14 s) performed 5 maximal trials over a 20-m distance in the following conditions: unloaded and with loads from 15% to 40% of the athlete’s body mass (BM). In these calculations the sled mass and friction were taken into account. Contact and flight times, stride length, horizontal hip velocity (vh), and relative angles of hip, knee, and ankle (at touchdown and takeoff) were measured step by step. In addition, the horizontal force (Fh) and power (Ph) and maximal force (Fh0) and power (Ph0) were calculated. Results: vh, flight time, and step length decreased while contact time increased with increasing load (P 30%BM joint angles tended to decrease. Conclusion: The 20%BM condition represents the optimal overload for peak power production at this load sprinters reach their highest power without significant changes in their running technique (eg, joint angles)