LONGITUDINAL-STUDY OF SKELETAL-MUSCLE ADAPTATIONS DURING IMMOBILIZATION AND REHABILITATION

This study describes the metabolic, morphologic, neurologic, and funct ional adaptations observed in the plantar flexors during 8 weeks of lo wer leg immobilization and 10 weeks of physical therapy following ankl e surgery. A combination of magnetic resonance imaging and spectroscop y, isokinetic and isometric muscle testing, and simple functional test s revealed many adaptive changes due to immobilization, including atro phy, loss of muscle strength, reduced central activation, increase in fatigue resistance, and an increase in inorganic phosphate content. Af ter 10 weeks of physical therapy all alterations were reversed, with t he exception of a remaining 5.5% deficit in total muscle cross-section al area. (C) 1998 John Wiley & Sons, Inc.