Comparison of the effects of fatigue on kinematics and muscle activation between men and women after anterior cruciate ligament reconstruction.

OBJECTIVES

Studies comparing the effects of fatigue between men and women after anterior cruciate ligament (ACL) reconstruction are lacking. The purpose of this study was to compare the effects of muscle fatigue on trunk, pelvis and lower limb kinematics and on lower limb muscle activation between male and female athletes who underwent ACL reconstruction.

DESIGN

Cross-sectional study.

SETTING

Laboratory setting.

PARTICIPANTS

Fourteen recreational athletes (7 males and 7 females) with unilateral ACL reconstruction participated of this study.

MAIN OUTCOME MEASURES: Trunk, pelvis and lower limb kinematics and muscle activation of the vastus lateralis, gluteus medius and gluteus maximus were evaluated during a single-leg drop vertical jump landing before and after a fatigue protocol.

RESULTS

Females had greater peak knee abduction after fatigue in relation to before fatigue (P = 0.008), and in relation to men after fatigue (P = 0.011). Also, in females, peak knee abduction was greater in the reconstructed limb in relation to the non-reconstructed limb after fatigue (P = 0.029). Males showed a greater mean amplitude of activation of the vastus lateralis muscle after fatigue in relation to before fatigue (P < 0.001).

CONCLUSIONS

Muscle fatigue produced kinematic alterations that have been shown to increase the risk for a second ACL injury in female athletes.