Age-related changes in human posture control: motor coordination tests.

Postural responses to support surface displacements were measured in 214 normal human subjects ranging in age from 7 to 81 y. Motor tests measured leg muscle electromyographic (EMG) latencies, body sway, and the amplitude and timing of changes in center of pressure displacements in response to sudden forward and backward horizontal translations of the support surface upon which the subjects stood. There were small increases in both EMG latencies and the time to reach the peak amplitude of center of pressure responses with increasing age. The amplitude of center of pressure responses showed no change with age if the amplitude measures were normalized by a factor related to subject height. In general, postural responses to sudden translations showed minimal changes with age, and all age-related trends that were identified were small relative to the variability within the population.