Gender differences in three-dimensional pelvic behavior during maximal sprint running.

Background: Previous studies on joint kinetics in female during maximal sprinting have been limited to lower-limb kinetics; however, we hypothesized that female's sprinters have greater lumbosacral free leg side lateral flexion torque and lower lumbosacral free leg side torsional torque than male's sprinters. The present study aimed to examine the stiffness parameters, three-dimensional pelvic behavior, and kinetics in female's sprinters compared with male's sprinters.

Methods: The three-dimensional (3D) kinematics and force data during regular 60-m sprints starting from a crouching start position in eight female's and male's sprinters were captured using a motion capture system and force platform. Stiffness parameters, three-dimensional pelvic behavior, and kinetics were calculated.

Results: Female's sprinters had significantly lower vertical stiffness compared to male's sprinters. Additionally, female's sprinters had significantly the greater lateral flexion of the pelvis toward the free leg side angle and integrated contributory component of the free leg side lateral flexion angular impulse during the stance phase compared to male's sprinters. Furthermore, female's sprinters had significantly lower step frequency and an integrated contributory component of the free leg side rotation angular impulse during the stance phase and in total compared to male's sprinters.

Conclusions: The lateral flexion of the pelvis toward the free leg side observed in female's sprinters during stance leg toe-off may contribute to the upward movement center of mass. The lower lumbosacral torsional torque towards the free leg side in female's sprinters may lead to delayed leg recovery motion after stance leg toe-off, resulting in a lower step frequency.