Training of the sprint start technique with biomechanical feedback.

The purpose of this study was to improve the individual starting technique of eight top junior sprinters using biomechanical feedback training. Three technical parameters (blocks spacing to the start line, knee angle of the front leg and proportion of body mass falling on the hands) were varied. The horizontal velocity at take-off and the time to 10 m were the criteria used to evaluate the effect of the technical changes. All of the parameters were measured simultaneously and the athletes were provided with feedback immediately after each attempt. Seven of eight sprinters showed a statistically significant improvement in starting performance after modifying the position of their blocks. The improvement in 10-m time and horizontal velocity at take-off did not correlate significantly. The power exerted during the starting action correlated significantly with the time to 10 m. Therefore, it was concluded that effective biomechanical feedback during the training of the sprint start should use power exerted as the principal criterion because horizontal velocity shows an intra-individual optimal trend in improvement.