kinematic, ground reaction force, taekwondo, stance position.

The aims of this study were, firstly to compare mechanical variables in the roundhouse kick in taekwondo according to three stance positions (0?, 45?, 90?). And secondly, to analyze the relationship between the GRF and kinematical variables in each of the three stance positions. Two high level athletes participated in the study. Mechanical analysis was measured by two 3-D force plates and eight camera motion capture system. Data analyses were processed using Visual 3D software. From the 0? and 45? stance positions taekwondo players kicked in lower execution time and total response time than the 90? stance position (p < 0.05). Moreover, the GRF predicted a high percentage of the variance of the time to the GRF peak and the execution time.Finally, the stance position affects the mechanical performance of the kick of taekwondo athletes; that is, the 90? stance position seems less efficient performance than 0? and 45? stance positions