The influence of different shoe models and the trial number on sprinting performance in soccer shoe testing. A pilot study.

The purpose of this study was to identify influence of the shoe model, test order and their interaction in soccer shoe testing. Twenty-five amateur soccer players completed four straight-line 30-meter sprints followed by four change-of-direction (COD) sprints and after each sprint the shoe model was changed in a quasi-randomized test order. For straight-line sprinting, mechanical properties (theoretical maximal sprinting velocity (V0), theoretical maximal horizontal force (F0rel), maximal horizontal sprinting power (Pmaxrel), 10-meter, 20-meter, and 30-meter sprint time were computed from continuous velocity data captured from a laser device and in the COD-test, sprint time was measured. There were no main effects of shoe model or test order. But there was an interaction effect from shoe model to test order for V0, 20-meter, and 30-meter time. This shows that there was an influence in which sprint trial the respective shoe model was used. Moreover, these results suggest that the occurring fatigue while sprint testing affects the ability to generate horizontal force more at higher sprinting velocities than at low sprinting velocities. Consequently, this information is important to optimize shoe testing by minimizing unsystematic variance and thus shoe models can be better compared.