Leg Dominance May Not Be a Predictor of Asymmetry in Peak Joint Moments and Ground Reaction Forces During Sit-to-Stand Movements

Sit-to-stand transfer is a common prerequisite for many daily tasks. Literature often assumes symmetric behavior across the left and right side. Although this assumption of bilateral symmetry is prominent, few studies have validated this supposition. This pilot study uniquely quantifies peak joint moments and ground reaction forces (GRFs), using a Euclidian norm approach, to evaluate bilateral symmetry and its relation to lower limb motor-dominance during sit to stand in ten healthy males. Peak joint moments and GRFs were determined using a motion capture system and inverse dynamics. This analysis included joint moment contributions from all three body planes (sagittal, coronal, and axial) as well as vertical and shearing GRFs. A paired, one-tailed t test was used, suggesting asymmetrical joint moment development in all three lower extremity joints as well as GRFs (P < .05). Furthermore, using an unpaired two-tailed t test, asymmetry developed during these movements does not appear to be predictable by participants' lower limb motor-dominance (P < .025). Consequently, when evaluating sit-to-stand it is suggested the effects of asymmetry be considered in the interpretation of data. The absence of a relationship between dominance and asymmetry prevents the suggestion that one side can be tested to infer behavior of the contralateral.