Abstract
A number of work and leisure activities that involve voluntarily pushing are performed while standing asymmetrically. The goal of the study was to investigate anticipatory (APAs) and compensatory (CPAs) postural control during pushing performed while standing in the symmetrical and asymmetrical stance. Ten healthy volunteers stood with feet parallel and in staggered stance with right foot forward or backward and were instructed to use both the hands to push the handle of the attached to the ceiling pendulum Bilateral EMG activity of the trunk and leg muscles and the center of pressure (COP) displacements in the anterior-posterior and medial-lateral directions were recorded and analyzed during the APAs and CPAs. There were differences in the EMG activity and the COP displacement between the parallel and the staggered stance. In particular, the COP displacements in the medial-lateral direction were significantly larger in the staggered stance than in the parallel stance. Moreover, in the staggered stance, the APAs in the thigh muscles of the backward leg were significantly larger and the CPAs were smaller than in the forward leg. Moreover, generation of substantial APAs was always resulted in smaller CPAs regardless of the type of the stance. There was no difference in the EMG activity of the trunk and shank muscles between the stance conditions during both, APAs and CPAs. The study outcome suggests the importance of stance characteristics in control of posture during pushing.