Introduction: Hamstring strain is one of the most common lower-limb injuries in athletes and is often accompanied by persistent neuromuscular impairments that may affect knee stability and increase the risk of re-injury. This study examined the effects of two landing patterns (trunk-extended vs. trunk-flexed) on the EMG median frequency of lower-limb muscles in male volleyball players with a history of hamstring strain compared with healthy peers.

Methods: This cross-sectional comparative study included 16 healthy male volleyball players and 16 male volleyball players with hamstring strain, recruited purposively and assigned to control and case groups. Surface EMG of selected muscles was recorded during a drop-landing task from a 30-cm box. Data were analyzed using repeated-measures ANOVA at a significance level of 0.05.

Results: A significant main effect of group was found for the median frequency of the rectus femoris (p=0.022) and biceps femoris (p=0.035). For the biceps femoris, both the main effect of task (p=0.016) and the group*task interaction (p=0.044) were significant. For the vastus medialis, the main effect of task (p=0.017) and the group*task interaction (p=0.029) were also significant.

Conclusion: Athletes with hamstring strain exhibit trunk-dependent differences in neuromuscular activation, and trunk-flexed landing may facilitate a more favorable distribution of mechanical load. Rehabilitation emphasizing trunk-flexed landing drills and quadriceps–hamstring coordination may reduce recurrence risk and support a safer return to sport.

Keywords: Hamstring Muscles; Landing; Frequency spectrum; Electrical activity