Effect Of Exercise on Myosin Heavy Chain (MHC)

Skeletal muscle is a heterogeneous tissue composed of fast and slow fibers. One of the features of skeletal muscle is the highly organized structure that provides variety of functional capabilities ofthis tissue. Muscle fibers are also able to regulate their phenotypic properties in response to different functional needs. Types of muscle fibers can be identified by differences in their structural and functional properties. The main difference between muscle fibers is related to the contractile fibers of actin and myosin. Actin is involved in important cellular processes, including muscle contraction. Myosin is a molecular engine that converts the chemical energy released by ATP into mechanical energy. Energy production in myosin occurs through a number of ATPase in the myosin heavy chain. The myosin heavy chain isoform determines the maximum velocity and shortening force with respect to the cross-sectional area of each muscle fiber. Differences in energy costs and ATP phosphorylation potentials in different types of fast and slow fibers can be effective in the exchange of MHC isoforms. It seems that exercise can change the MHC isoforms through various mechanisms and consequently change the muscle fiber phenotype. In this review, we persent the potential effect of exercise on MHC isoforms.