Factors Contributing to the Success of Counterattacks Examined Through Reaction Time

<b>Background:</b> Reaction time (RT) and movement time (MT) are key indicators of cognitive-motor processing. However, in interpersonal sports such as kendo, responders sometimes win against leaders who initiate movement first, suggesting complex temporal dynamics underlying reactive performance. <b>Purpose:</b> This study aimed to experimentally demonstrate the phenomenon of a responder winning against a leader who moves first and to investigate the reasons for such victories through MT and RT. <b>Research Design:</b> Two experiments were conducted. In the first, we recreated a situation in which counterattacks typically occur in kendo matches, confirming that responders won in approximately half the trials. Although responders had significantly shorter MTs than leaders, this alone could not explain their victories. The second experiment involved participants reacting to the sudden illumination of a light-emitting diode (LED) to perform a kendo men strike, thus measuring their simple RT. <b>Study Sample:</b> The experiments involved skilled university kendo athletes with over 12 years of experience who trained regularly. <b>Data Collection and/or Analysis:</b> The winner was identified based on high-speed camera recordings, while MT was calculated using both ground reaction force data and video analysis. RT was determined from the ground reaction force data. <b>Results:</b> Responders could shorten their RTs by detecting subtle changes in their opponents' movements early and reacting quickly. <b>Conclusions:</b> In interpersonal contexts, responding to gradual changes in an opponent's actions rather than to sudden stimuli may lead to shorter RTs, potentially contributing to a responder's win.