Optimal mechanical force‐velocity profile for sprint acceleration performance

Abstract

The aim was to determine the respective influences of sprinting maximal power output ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>P</mml:mi> <mml:mi>H</mml:mi></mml:msub> <mml:mo>max</mml:mo></mml:mrow> </mml:math> ) and mechanical Force-velocity (F-v) profile (ie, ratio between horizontal force production capacities at low and high velocities) on sprint acceleration performance. A macroscopic biomechanical model using an inverse dynamics approach applied to the athlete's center of mass during running acceleration was developed to express the time to cover a given distance as a mathematical function of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>P</mml:mi> <mml:mi>H</mml:mi></mml:msub> <mml:mo>max</mml:mo></mml:mrow> </mml:math> and F-v profile. Simulations showed that sprint acceleration performance depends mainly on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>P</mml:mi> <mml:mi>H</mml:mi></mml:msub> <mml:mo>max</mml:mo></mml:mrow> </mml:math> , but also on the F-v profile, with the existence of an individual optimal F-v profile corresponding, for a given <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>P</mml:mi> <mml:mi>H</mml:mi></mml:msub> <mml:mo>max</mml:mo></mml:mrow> </mml:math> , to the best balance between force production capacities at low and high velocities. This individual optimal profile depends on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>P</mml:mi> <mml:mi>H</mml:mi></mml:msub> <mml:mo>max</mml:mo></mml:mrow> </mml:math> and sprint distance: the lower the sprint distance, the more the optimal F-v profile is oriented to force capabilities and vice versa. When applying this model to the data of 231 athletes from very different sports, differences between optimal and actual F-v profile were observed and depend more on the variability in the optimal F-v profile between sprint distances than on the interindividual variability in F-v profiles. For a given sprint distance, acceleration performance (<30 m) mainly depends on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>P</mml:mi> <mml:mi>H</mml:mi></mml:msub> <mml:mo>max</mml:mo></mml:mrow> </mml:math> and slightly on the difference between optimal and actual F-v profile, the weight of each variable changing with sprint distance. Sprint acceleration performance is determined by both maximization of the horizontal power output capabilities and the optimization of the mechanical F-v profile of sprint propulsion.