Skeletal muscle hypertrophy – physiological mechanisms

Abstract

The development of muscular mass was always a challenge for athletes and sport experts, especially when sport is based on muscle strength. Increasing of cross-sectional area of certain skeletal muscle is of outmost importance for athlete because the intensity of maximal muscle contraction is in direct relationship to transversal dimension of the muscle. The aim of this paper is to make a review of physiological mechanisms which are suggested as explanation for muscle hypertrophy. The good understanding of physiological mechanisms is needed to planning the successful strength training. It is well documented that muscle hypertrophy could occur only when external load is prevailed. The proposed physiological mechanisms which lead to muscle hypertrophy are divided into three groups: 1) mechanically induce tension 2) metabolic stress and 3) muscle damage. Depending on the part of the muscle cell which dominantly contributes to the increasing of the muscle volume hypertrophy could be sarcoplasmic or miofibrilar. Cellular mechanisms which explain the hypertrophy involve the myogenic satellite cells, several signal transducing pathways (Akt/ Mammalian Targetof rapamycin pathway; Mitogen-Activated protein kinase pathway; Calcium depending pathway); hormones and citokins (IgF, GH, testosteron). Scientific based knowledge of muscle hypertrophy is necessary for athletes and sport experts to design oprimal training volume (load, intensity, duration, frekquency, ect.) to achieve maximal increase in muscle volume and muscle strength for better sport performance.