Gender differences in the control of the upper body accelerations during level walking.

Despite the common knowledge about an evident tendency of females to walk with more style and poise than males, gender differences in walking mechanics have received little attention. Upper body oscillations during level walking are person specific and in able bodied individuals are characterised by an attenuation of the linear acceleration progressing from pelvis level up to head level. The manner of controlling head accelerations in the anatomical planes has recently been covered in the literature, but gender differences have been rarely investigated. This study aims to asses the existence of these differences. Two groups of young healthy volunteers (20 males, 23+/-2 y.o., and 20 females, 23+/-3 y.o.) were asked to walk along a linear pathway and upper body accelerations were directly measured using wearable inertial sensors located along the cranio-caudal axis at pelvis, shoulder, and head levels. Both groups managed to attenuate the antero-posterior accelerations, although the females exhibited a more effective shoulder to head attenuation. Group differences were found in the medio-lateral direction: not only were the males unable to attenuate the accelerations progressing from pelvis to shoulder levels to the same extent as the females, but head accelerations were even larger than those at the shoulder level. The females' ability to implement a more effective attenuation, possibly indicating a better control strategy, allowed them to reach head accelerations equivalent to those of the males despite higher pelvis accelerations. Although an explanation for these gender differences calls for further investigations, they should always be considered when upper body kinematics is used for clinical assessment.