The Evolution of Skeletal Muscle Plasticity in Response to Physical Activity and Inactivity

Abstract The goal of this chapter is to trace the evolution of scientific inquiry on skeletal muscle plasticity during the past century along three central, integrated topics: (1) identifying the fundamental properties of skeletal muscle centered on the structural and functional features of the motor unit, which provides the gradation in movement and force generation capacity of living organisms; (2) examining the differential properties of fast versus slow skeletal muscle motor units and their adaptive capacity in response to acute and chronic endurance exercise; and (3) addressing the evolution of studies concerning alterations in loading state in the regulation of muscle mass, and establishing the features of both the contractile and metabolic phenotype in contributing to the plasticity of skeletal muscle.