Sex differences in anticipatory postural adjustments during rapid single leg lift
The aim of this study was to assess the influence of sex on the kinetic, kinematic and neuromuscular correlates of anticipatory postural adjustments (APAs) during a single leg lift task performed by healthy participants. Fifty healthy age and body mass index matched participants (25 women and 25 men) performed 20 single leg lift task (hip flexion to 90 ° as quickly as possible) with their dominant and their non-dominant lower limbs. A force plate was used to determine the medial-lateral displacement of the center of pressure (COPML), and the initiation of weight shift (T0); kinematics was used to determine leg lift (T1); and electromyography was used to determine onset times from eight muscles: bilateral external oblique, internal oblique and lumbar multifidus, and unilateral (stance limb) gluteus maximus and biceps femoris. Movement control limb dominance was included in the analysis. Statistically significant interactions between sex and limb dominance (p < .001) were observed for T1, COPML, and muscle onsets. Also, statistically significant main effect of sex on T0 was observed. Women showed increased APA time (T1) and magnitude (COPML) in their dominant limbs compared to men. Such differences between sexes did not occur in the non-dominant limb. Women recruited proximal muscles later than their man counterparts. Overall, women appear to have a stronger effect of limb dominance on their anticipatory postural control strategy which requires further investigation. The findings of the current study indicate that women and men differ in their anticipatory postural control strategy for rapid single leg lift.