Gender differences in joint torque focused on hip internal and external rotation during a change in direction while walking.

[Purpose] To investigate lower-extremity joint torque during walking direction changes, focused on gender differences in pelvic width. [Subjects and Methods] Healthy males and females (n=10) changed direction while walking by side-stepping (SS) and crossover stepping (CS), stepping the left leg to the left or right, respectively, over the right leg. Movements were recorded using four infrared cameras, and ground reaction force of each lower extremity measured using two force platforms. Joint torque of each lower extremity was calculated, and each joint peak torque among walking, SS and CS was compared between genders. Moreover, correlation between joint torque showed a gender difference and width of pelvis normalized by width of shoulder (P/S ratio) was examined. [Results] Right external and internal rotation torques during CS were higher in males. Left- and right-ankle plantar flexion torques were also higher in males during CS, while the P/S ratio was larger in females, with a positive correlation between P/S ratio and hip external and internal rotation torques. [Conclusion] No gender differences were found in joint torque during walking and SS, but only during CS. The hip external and internal rotators are necessary for smooth CS in females in terms of P/S ratio.