Purpose: The purpose of this study was to investigate the effects of specialized Kyokushin karate exercises on the activity of leg muscles and the height of the medial longitudinal arch in adolescent girls with foot pronation.
Methods: This study recruited twenty-four adolescent girls with foot pronation who voluntarily agreed to participate and were randomly assigned to either a training group (n=12) or control group (n=12). The training program consisted of eight weeks of specialized Kyokushin karate exercises. The fibularis longus, tibialis anterior, and lateral gastrocnemius muscles activity was measured during single-leg landing using surface electromyography. The medial longitudinal arch height was measured using the navicular drop test. All statistical analyses, including independent and paired t-tests, were conducted using SPSS software, version 26 at a significance level of 0.05. 
Results: The results showed that following eight weeks of specialized Kyokushin karate exercises, there was a significant increase in the activity levels of the tibialis anterior (P=0.005) and lateral gastrocnemius (P=0.04) muscles in the training group compared to the control group. However, there was no significant change in the activity of the fibularis longus muscle in the training group compared to the control group (P>0.05). Within the training group, there was a significant increase in the activity of all three measured muscles (fibularis longus, P=0.009; tibialis anterior, P=0.008; and lateral gastrocnemius, P=0.008) from post-test to pre-test (P<0.05). Additionally, the study found that the amount of navicular drop in the training group was significantly reduced compared to the control group (P=0.04) after eight weeks of training
Conclusion: This study demonstrated that eight weeks of specialized Kyokushin karate exercises resulted in a significant increase in the activity levels of the tibialis anterior and lateral gastrocnemius muscles in adolescent girls with foot pronation. These exercises also improved the height of the medial longitudinal arch, indicating a potential solution for correcting flat feet. Therefore, we recommend Kyokushin karate exercises to improve muscle activity and arch height in adolescent girls with foot pronation.