Unilateral Hamstring Muscle Strengthening Exercises Can Improve Hamstring Asymmetry and Increase Jumping Performance in Sub-Elite Badminton Athletes

This study aimed to determine the effect of 10 weeks of unilateral training on asymmetry and jumping performance in sub-elite badminton athletes. 23 out of 41 badminton athletes who met the inclusion criteria were taken as samples in this study. Selected samples will be given unilateral exercise interventions in the form of Swiss ball hamstring curl exercises and single leg bridge for ten weeks with a frequency of exercise 3 times a week. Data were collected two times before the intervention (pretest) was given and after the intervention (posttest). The measurement uses the Norbord test to determine the condition of hamstring asymmetry and the Counter Movement Jump (CMJ) jump test to determine jump height. The results showed that there was a significant decrease in the percentage of hamstring asymmetry p ≤ 0.001 (Pretest: 20.26±10.25 % to Posttest: 9.20±3.51 %) and has a large effect size with a Cohen's d value of 1.443, and an increase in jump height p ≤ 0.001 (Pretest: 33.06±4.93 cm to Posttest: 35.17±4.54 cm) and has a medium effect size with a Cohen's d value of 0.447. The conclusion is that 30 unilateral exercises for ten weeks can improve hamstring asymmetry above 10% and increase jumping performance in badminton athletes. Keywords: Hamstring Asymmetry, Jump performance, Unilateral exercise