Effects of short-term hand immobilization on motor functions across domains in adults.

Abstract

Short-term limb immobilization is known to impair muscle strength; however, its effects across distinct domains of motor function remain incompletely characterized. In this study, we assessed the effects of 72-h of hand immobilization on motor functions in healthy adults. Twenty-eight participants were randomized to an immobilization or control group and completed a motor test battery before and after the intervention. The battery assessed maximal and explosive strength, quantified as maximal voluntary contraction (MVC) force and rate of force development (RFD), fatigability during sustained maximal contractions, force steadiness during submaximal contractions, and manual dexterity. Immobilization induced domain-specific impairments in motor performance. MVC force and RFD declined significantly following immobilization, indicating susceptibility of maximal and explosive strength to short-term disuse. In contrast, no significant changes were observed in the selected parameters of fatigability during sustained maximal contractions, including the fatigue time constant and plateau force. Force steadiness showed a selective increase in relative force variability, whereas absolute force variability remained unchanged. Manual dexterity was not reduced from baseline, but immobilization attenuated the test-retest performance improvements observed in the control group and contralateral non-immobilized hand. These findings demonstrate that hand immobilization induces task- and domain-specific alterations in motor performance rather than a uniform decline, preferentially affecting motor domains that require high force production.