Effects of Hamstring Asymmetry on Agility and Leg Power in Badminton Players

Purpose: This study aims to examine the impact of hamstring muscle asymmetry on badminton athletes' leg agility and power, considering that these two physical aspects are essential for the performance of dynamic and complex movements in badminton. Method: This study was conducted with an ex post facto design on 41 active male badminton athletes in Surabaya, aged 16–20 years, with a normal BMI and a minimum of 5 years of training experience. Subjects were divided into two groups based on the level of hamstring asymmetry: the AH group (hamstring asymmetry; n = 23) with asymmetry of more than 10% and the NAH group (non-hamstring asymmetry; n = 18) with asymmetry of less than 10%. Data was collected through the Illinois Agility test, Norbord test for hamstring asymmetry, and a force plate to measure leg power. Findings: The AH group exhibited significantly slower agility times (11.83 ± 1.21 s) compared to the NAH group (10.81 ± 0.89 s; p = 0.006, Cohen’s d = 0.96). Additionally, leg power was markedly lower in the AH group (2600.61 ± 643.23 W) than in the NAH group (3221.17 ± 618.49 W; p = 0.003, Cohen’s d = 0.98), indicating large effect sizes. These findings suggest that hamstring asymmetry exceeding 10% adversely impacts agility and power, which are critical for badminton performance. Conclusion: Hamstring asymmetry significantly affects athletes' agility and leg power abilities, which impacts their performance in badminton matches that require changes in direction and explosive movements.