Effect of light stimuli on squat jump performance

We aimed to compare the effects of intentional jump conditions (IJC) and reactive jump conditions (RJC) using light stimuli on SJ performance, focusing on differences between track and field sports and football. Twenty-five university track and field athletes (TF group) and 25 male football players (F group) performed four SJs, receiving intentional or reactive jump verbal instructions. Reaction time (RT), jump height (JH), peak force (PF), peak rate of force development (PRFD), and average rate of force development (ARFD) during the SJ were recorded. Unpaired t-tests were used to evaluate differences in each variable between IJC and RJC, while two-way analysis of variance was used to assess differences between conditions and between sports. For all participants, JH and PF were significantly higher during IJC, whereas PRFD and ARFD were higher during RJC (p < .05). The TF group showed significantly higher JH and PF and significantly lower RT than the F group. In the F group, PRFD and ARFD increased significantly under RJC (p < .05), while PF did not decrease across conditions. These findings suggest that light stimulation affects SJ performance differently by sport. Notably, football players may enhance force development velocity under reactive conditions while maintaining force output.