Influence of Hamstring Tightness on Postural Control Strategies during Single Leg Stance

Purpose: To compare postural control strategies during single-leg stance between individuals with hamstring tightness and those with normal hamstring extensibility.Methods: Twenty healthy male adults in their 20s with right-leg dominance participated and were assigned to a hamstring tightness group (HT) or a control group based on the passive straight-leg raise (PSLR) performance.Postural control was assessed during single-leg stance (30 seconds, three trials, eyes open) using the LEGSys system (Biosensics, Cambridge, MA, USA).The outcome variables included mediolateral (ML) range, anteroposterior (AP) range, sway area, and sway velocity for center of mass (COM), hip angle, and ankle angle.Results: Compared to the control group, the HT group showed a significantly greater COM sway area and greater AP range and sway area of hip angle during single-leg stance (p< 0.05).No significant between-group differences were observed for the remaining COM and hip variables (p> 0.05).For ankle angle, no significant differences were observed in the ML range, AP range, sway area, or sway velocity (all p> 0.05).Conclusion: The hamstring tightness was associated with selective alterations in postural control during single-leg stance, characterized by an increased COM sway area and greater hip kinematic excursions in the AP direction, while ankle kinematics remained comparable between groups.These findings suggest that the hamstring tightness may influence postural control strategies during the static singleleg stance by altering COM regulation and hip joint control rather than ankle-level adjustments.