Effect of lower-limb fatigue on kinematic variables during an unanticipated block among adolescent female volleyball players.

backgroundPrevious studies investigating the effects of muscle fatigue on lower limb kinematics in adolescent volleyball players have reported contradictory findings. Thus, the present study aimed to assess the effect of lower-limb fatigue on the kinematic variables during an unanticipated block among adolescent female volleyball players.

methodsGiven the inclusion criteria, 20 adolescent female volleyball players were selected through a convenience sampling method. In the pre-test stage, each subject performed an unanticipated single-leg jump-landing maneuver, the data of which were recorded by using a motion analyzer. Then, the intervention of a volleyball-specific lower-limb fatigue protocol was applied and the players were re-evaluated.

resultsThe results represented a significant decrease in knee and hip joint flexion, as well as a significant increase in ankle inversion at the initial contact after applying the fatigue protocol(P ≤ 0.05). However, no significant difference was observed in terms of the other kinematic variables of the knee, ankle, and hip joints at the initial contact and landing peak(P ≥ 0.05).

conclusionsReduced hip and knee flexion, along with increased ankle inversion, were identified as high risk movement strategies observed at initial contact. These findings suggest that fatigue may influence the proper kinematic pattern of lower-limb, leading to changes in movement control during landing and consequently increasing the risk of knee injuries in athletes. TRIAL REGISTRATION NUMBER: Considering that our research is semi-experimental, it does not need a clinical trial number.