Feedforward and feedback control for gait and balance

Postural control during standing and walking is an important topic when study fall related stability among elderly. Based on the literature and our own data, we suggest the main mechanism that responsible for the determination of postural control during standing among elderly, or patient population, is due to reduced functionality in the sensory system. This includes the sensory organ - tactile, proprioception, vision, vestibular system, sensory nerves conduction velocity and sensory process in the central nervous system. But the main mechanism that responsible for the deterioration of postural control during walking among elderly, or patient population, is due to impairment with in the motor system. Muscle strength, motor nerve function (motor unit recruitment and motor nerve conduction velocity), and coordination among different limbs and the trunk are the main elements that responsible for this mechanism. However, people with peripheral neuropathy have reduced foot sole cutaneous sensation and reduced nerve conduction velocity. This reduction of tactile sensation and slowed signal transmission are highly correlated with the standing balance but to a less extend with walking stability. Rehabilitation effort focused on sensory recovery is more effective than motor rehabilitation among this population. Therefore, postural stability during standing is mainly controlled by a feedback loop, where feedforward control is mainly responsible for postural stability during walking.