Biomechanics of Vertical Posture and Control with Referent Joint Configurations.

Our study compared the results of two methods of analysis of postural sway during human quiet standing, the rambling-trembling (-) decomposition and the analysis of the point of intersection of the ground reaction forces ( analysis). Young, healthy subjects were required to stand naturally and with an increased level of leg/trunk muscle co-activation under visual feedback on the magnitude of a combined index of muscle activation (muscle mode). The main findings included the shift of toward higher frequencies and strong correlations between and when the subjects stood with increased muscle co-activation. We interpret the results within the idea of whole-body control with a set of primitives associated with referent coordinates in the joint configuration space.