Fatigue Affects Body Acceleration During Vertical Jump And Agility Performance In Elite Young Badminton Players

Abstract

PURPOSE: Ability of change of direction and explosive power of lower extremity during jumping are important competency for badminton players. Declines in physical fitness during games could easily influence sports performance. Therefore, the purpose of this study was to investigate the influence of fatigue on body accelerations during vertical jump and agility drill in elite young badminton players. METHODS: A total of 38 elite badminton players were recruited from a high-school team. For obtaining the changes of the whole-body acceleration, a nine-axes inertial measurement unit (MTw Awinda System, Xsens, Netherlands) was secured on the level of L4-L5. Participants were requested to perform three best vertical jumps and agility-T test before and after a fatigue protocol. Mean (root mean square), peak, and rate of acceleration change were calculated for time-domain analysis, and median frequency was identified after Fast Fourier Transform for frequency-domain analysis. In addition, height of vertical jumping and total finish duration and duration of each direction of the agility-T test were also recorded. RESULTS: The jumping height significantly decreased (p < 0.001), and duration of left side-shuffle running significantly increased (p = 0.021) after fatigue. For the vertical jump test, both mean and rate of change in downward acceleration during squatting subphase significantly increased after fatigue (p = 0.006 and p = 0.026, respectively). Both mean and peak in upward acceleration during jumping subphase significantly increased after fatigue (p = 0.018 and p = 0.010, respectively). No changes were observed in frequency-domain analysis. For the agility-T test, peak, range of change and mean of mediolateral acceleration significantly increased during the leftward shuffle running (p = 0.039, p = 0.038 and p = 0.002, respectively). Median frequency also significantly increased in this direction (p = 0.042). CONCLUSIONS: Fatigue could affect body accelerations in both vertical and horizontal directions during vertical jump and agility-T tests as well as sports performance for badminton players. Current findings imply declined neuromuscular control of the lower extremity might be occurred after fatigue which provides a rationale for specific training programs in badminton players.