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Calcif Tissue Int (2015) 96:183195
DOI 10.1007/s00223-014-9915-y
REVIEW
Skeletal Muscle: A Brief Review of Structure and Function
Walter R. Frontera Julien Ochala
Received: 9 July 2014 / Accepted: 16 September 2014 / Published online: 8 October 2014 Springer Science+Business Media New York 2014
Abstract Skeletal muscle is one of the most dynamic and plastic tissues of the human body. In humans, skeletal muscle comprises approximately 40 % of total body weight and contains 5075 % of all body proteins. In general, muscle mass depends on the balance between protein synthesis and degradation and both processes are sensitive to factors such as nutritional status, hormonal balance, physical activity/exercise, and injury or disease, among others. In this review, we discuss the various domains of muscle structure and function including its cytoskeletal architecture, excitation-contraction coupling, energy metabolism, and force and power generation. We will limit the discussion to human skeletal muscle and emphasize recent scientic literature on single muscle bers.
Keywords Muscle actions Metabolism Force
generation Exercise Sarcopenia Dystrophy
Introduction
Skeletal muscle is one of the most dynamic and plastic tissues of the human body. In humans, skeletal muscle comprises
approximately 40 % of total body weight, contains 5075 % of all body proteins, and accounts for 3050 % of whole-body protein turnover. Muscle is mainly composed of water (75 %), protein (20 %), and other substances including inorganic salts, minerals, fat, and carbohydrates (5 %). In general, muscle mass depends on the balance between protein synthesis and degradation and both processes are sensitive to factors such as nutritional status, hormonal balance, physical activity/exercise, and injury or disease, among others. The various protein compartments (structural, contractile, and regulatory) have received signicant scientic attention because of their important contribution to mobility, exercise capacity, functioning, and health.
Skeletal muscle contributes signicantly to multiple bodily functions. From a mechanical point of view, the main function of skeletal muscle is to convert chemical energy into mechanical energy to generate force and power, maintain posture, and produce movement that inuences activity, allows for participation in social and occupational settings, maintains or enhances health, and contributes to functional independence. From a metabolic perspective, the roles of skeletal muscle include a contribution to basal energy metabolism, serving as storage for important substrates such as amino...