CHANGES IN SPRINT PERFORMANCE AND KINETICS DURING THE ACCELERATION PHASE OF RUNNING OF A WORLD RECORD HOLDER

INTRODUCTION: Previously, it was reported that faster athletes tend to produce vertical ground reaction force (GRF) impulse during the acceleration phase of sprint (Hunter et al. 2005). The purpose of this study was to investigate changes in sprint performance and kinetics during the acceleration phase of running for a world record holder

Combinations of loading conditions with significant differences in spatiotemporal variables.

Combinations of loading conditions with significant differences in spatiotemporal variables.</p

Example of each measurement variable plotted against step-averaged velocity.

Data are from one subject in 6 kg loading condition. Gray circles: Measured values. Black triangles: Values at every 0.5 m/s obtained using spline interpolation technique. A few subjects showed the rapid change in some variable near the maximal step-averaged velocity in resisted sprint (arrows) into “bouncing” manner. Therefore, steps at less than 98% maximal step-averaged velocity in each trial (vertical dashed line) were used for analysis. Fap: Anteroposterior ground reaction force. Fver: Vertical ground reaction force. RF: Ratio of stance-averaged Fap to resultant ground reaction force.</p

Ground reaction force variables as a function of running velocity.

Values are means ± standard deviations. Symbols in the figure indicate significant differences between loading conditions (p Fap: Anteroposterior ground reaction force. Fver: Vertical ground reaction force. RF: Ratio of Fap to resultant ground reaction force.</p

Individual values of spatiotemporal and GRF variables.

Individual values of spatiotemporal and GRF variables.</p

Spatiotemporal variables as a function of step-averaged velocity.

Values are means ± standard deviations. Symbols in the figure indicate significant differences between loading conditions (p < .05); e.g., “0–10” denotes a significant difference between 0 kg (unresisted sprinting) and 10 kg loading condition. Horizontal lines in panel c indicate velocity range in each loading condition in which values for all subjects were obtained.</p

Combinations of loading conditions with significant differences in ground reaction force variables.

Combinations of loading conditions with significant differences in ground reaction force variables.</p