the effects of neuromuscular and mental fatigue on knee kinematics and anterior cruciate ligament injury risk in male soccer players

Background: the majority of anterior cruciate ligament (acl) injuries are non-contact, occurring most frequently during landing or changing directions in sports activities. various factors, such as biomechanical and neuromuscular variables, have been implicated in these injuries. recent research highlights that both physical and mental fatigue might influence the risk factors for acl injuries by altering movement patterns during high-risk maneuvers. this study aimed to investigate the effects of neuromuscular and mental fatigue on knee kinematics and potential risk factors for acl injuries in male soccer players during landing and crossover-cutting maneuvers. methods: thirty professional male soccer players were randomly divided into three groups: physical fatigue (n=10), mental fatigue (n=10), and control (n=10). experimental groups performed landing and crossover-cutting maneuvers during pre- and post-fatigue states, with kinematic data collected using a seven-camera system and cortex software. the control group underwent identical maneuvers without fatigue protocols to ensure comparability of conditions across groups. the control group underwent the same tests without implementing fatigue protocols. statistical analysis was conducted using repeated measures anova to evaluate differences across groups and conditions.results: physical fatigue caused a significant decrease in knee flexion at initial contact (p = 0.002), while mental fatigue showed no significant effects on kinematics. group-by-time interaction effects were observed for knee flexion (p = 0.05), with pairwise comparisons revealing significant differences only in the physical fatigue group.conclusion: neuromuscular fatigue alters knee kinematics, increasing acl injury risk. coaches should prioritize training programs that enhance fatigue resistance and proper movement mechanics.