Muscular immobilization leads to a range of morphological as well as functional alterations. Changes occurring in individual representative muscle fiber types and muscular atrophy are among the most interesting morphological changes that can occur.
Immobilization of muscles results in a relative decrease in the number of slow acting muscle fibers and a relative increase in the volume of fast acting muscle fibers. In addition, reversible increases in non-synaptic acetylcholine receptors occur at the membrane of muscle fibers.
The present paper addresses the control the central nervous system has upon skeletal muscle contractions and the effect that muscular hypokinesia has on electrophysiological characteristics of muscle fibers as well as the recruitment of motor units.