Acceleration capability in elite sprinters and ground impulse: Push more, brake less?

Abstract Overground sprint studies have shown the importance of net horizontal ground reaction force impulse ( IMPH ) for acceleration performance, but only investigated one or two steps over the acceleration phase, and not in elite sprinters. The main aim of this study was to distinguish between propulsive ( IMPH +) and braking ( IMPH − ) components of the IMPH and seek whether, for an expected higher IMPH , faster elite sprinters produce greater IMPH +, smaller IMPH − , or both. Nine high-level sprinters (100-m best times range: 9.95–10.60 s) performed 7 sprints (2×10 m, 2×15 m, 20 m, 30 m and 40 m) during which ground reaction force was measured by a 6.60 m force platform system. By placing the starting-blocks further from the force plates at each trial, and pooling the data, we could assess the mechanics of an entire “virtual” 40-m acceleration. IMPH and IMPH + were significantly correlated with 40-m mean speed ( r =0.868 and 0.802, respectively; P