Acute and chronic neuromuscular electrical stimulation and postural balance: a review

Electro-induced (EI) muscle actions are largely used in healthy subjects to improve motor performance, in frail/older subjects to limit sarcopenia and mobility loss, and in pathological subjects to restore functional abilities after injury and/or surgical operation. Their effects on motor output (e.g., muscle strength and power, and motor performance) are relatively well known, but their effects on postural balance are not. However, postural balance turns out to be a determining factor for motor skills in terms of motor performance and prevention of falls (especially in older/frail and pathological subjects). Hence, this review addresses the acute and chronic effects of EI muscle actions on postural balance, comparing them to the effects of voluntary (VOL) muscle actions.

Narrative review.

In acute, fatigue-generating application, EI muscle actions impair postural balance but less than VOL muscle actions. In chronic application, EI muscle actions induce beneficial effects on postural balance in pathological and aged (or frail) subjects. However, they have no or very little impact on healthy and young subjects. In aged (and probably pathological) subjects, EI muscle actions alone or superimposed onto voluntary contractions (EI + VOL) are less efficient than VOL muscle actions in improving postural balance.

In practice, as part of populations too frail/fragile or unable (sarcopenic or pathological persons) to regularly undertake VOL motor tasks required to efficiently struggle against the loss of mobility and the risk of fall, the EI muscle actions turn out to be particularly relevant to implement.