Effects of target distance on select biomechanical parameters in taekwondo roundhouse kick

The aim of this study was to investigate the effects of target distance on temporal and impact force parameters that are important performance factors in taekwondo kicks. Forty-nine taekwondo athletes (age=24.5 +/- 5.9 years; mass=79.9 +/- 10.8kg) were recruited: 13 male experts, 21 male novices, 8 female experts, and 6 female novices. Impact force, reaction time, and execution time were computed. Three-way repeated measure ANOVAs revealed significant distance' effect on impact force, reaction time, and execution time (p=0.001). Comparisons between distance conditions revealed that taekwondo athletes kicked with higher impact force from short distance (17.6 +/- 7.5N/kg) than from long distance (13.1 +/- 5.7N/kg) (p<0.001), had lower reaction time from short distance (498 +/- 90ms) and normal distance (521 +/- 111ms) than from long distance (602 +/- 121ms) (p<0.001), and had lower execution time from short distance (261 +/- 69ms/m) than from normal distance (306 +/- 105ms/m) or from long distance (350 +/- 106ms/m) (p=0.003 and p<0.001, respectively). In conclusion, target distance affected the kick performance; as distance increases, impact force decreased and reaction time increased. Therefore, when reaction to a simple visual stimulus is needed, kicking from a long distance is not recommended, as longer time is required to respond.