Sylvain Dorel’s research while affiliated with Nantes Université and other places

This study aimed to compare the force (F) - velocity (v) - power (P) - time (t) relationships of female and male world-class sprinters. A total of one hundred distance-time curves (50 women and 50 men), were computed from international 100-m finals, to determine the acceleration and deceleration phases of each race: 1) mechanical variables describing the velocity, force and power output; and 2) F-P-v relationships and associated maximal power output, theoretical force and velocity produced by each athlete (Pmax, F0 and V0). The results showed that the maximal sprint velocity (Vmax) and mean power output (W.kg-1) developed over the entire 100-m strongly influenced 100-m performance (r > -0.80; p ≤ 0.001). With the exception of mean force (N.kg-1) developed during the acceleration phase or during the entire 100-m, all of the mechanicals variables observed over the race were greater in men. Shorter acceleration and longer deceleration in women may explain both their lower Vmax and their greater decrease in velocity, and in turn their lower performance level, which can be explained by their higher V0 and its correlation to performance. This highlights the importance of the capability to keep applying horizontal force to the ground at high velocities.

The aim of this study was to propose and validate a simple field method to determine individual force, velocity and power output properties of sprint running. On the basis of 5 split times, this method models the horizontal force an athlete develops over sprint acceleration using a macroscopic inverse dynamic approach. Low differences in comparison to force plate data support the validity of this simple method to determine force-velocity relationship and maximal power output, which constitutes interesting tools for sprint training and performance optimization. INTRODUCTION Sprint running is a key factor of performance in many sport activities, such as track and field events or team sports. This ability implies large forward acceleration, which has been related to the capacity to develop high amounts of horizontal power output onto the ground, i.e. high amounts of horizontal external force at various speeds over sprint acceleration [2, 4]. The overall mechanical capability to produce horizontal external force during sprint running is well described by the linear force-velocity (F-v) relationship [2, 5]. This relationship characterizes the mechanical limits of the entire neuromuscular system during sprint propulsion and is well summarized through the maximal force (F 0) and velocity (v 0) this system can develop [5] and the associated maximal power output (P max). Moreover, the slope of the F-v relationship determines the individual F-v mechanical profile, i.e. the ratio between force and velocity qualities, which has recently been shown to determine explosive performances, independently from the influence of P max [6]. These parameters are a complex integration of numerous individual muscle mechanical properties, morphological and neural factors affecting the total external force developed by lower limbs, but also of the technical ability to apply the external force effectively onto the ground. Recently, Morin and colleagues showed that sprint performances (6s-sprints, 100m-events or repeated sprints) are as much (or even more) related to the technical ability to applied force onto the ground as to the total force developed by lower limbs [3, 4].