In postures such as upright stance and self-supported sitting, sensory data from the visual, auditory, proprioceptive and vestibular systems are mapped onto appropriate muscle groups in a manner that will maintain balance. This mapping can be thought of as a control system that applies muscular force in a spatially and temporally appropriate fashion. Such a control system must be able to detect self-movement and generate appropriate opposing neuromuscular actions. In turn, the outcome of these neuromuscular actions will create an updated perception of self-movement. Thus postural control can be considered as a dynamical system.

Movement during quiet standing, sway, is primarily detected by perception of correlated optic flow on the retina and proprioception of changes in joint angles. Aging can result in loss of acuity in vision as well as proprioception. Acuity in these two senses may not be lost at an equal rate with respect to their contributions to stance. Thus, aging may require postural control to readapt to the changing accuracy of information from these senses.

The Human Dynamics Lab investigates hypotheses about postural control from the standpoint of a multi-segmented, coupled dynamical system. Participants are motion tracked in situations where the information from proprioception and vision may give conflicting perceptions. Resulting data are analyzed to recover coupling parameters relating interlimb coordination to age-related changes in postural control.