The effect of exercise intensity on the consumption of macromolecules

Valid Khaled gharb¹ dr. SEIFI-ASGSHAHR,FARNAZ²

1) Master s student in sports physiology (Department of Sports Physiology, Faculty of Educational Sciences and Psychology, Mohaghegh Ardabili University, Ardabil) (responsible)
2) Associate Professor of Sports Physiology Department (Sports Physiology Department, Faculty of Educational Sciences and Psychology, Mohaghegh Ardabili University, Ardabil)

IOI Code : XKZE-KKHGC
Publication : Second International Exercise Physiology Conference(sportuma2023.ir)
Abstract :
    Summary Skeletal muscle is a heterogeneous tissue consisting of fast and slow fibers. One of the characteristics of skeletal muscles is the organized structure of its fibers, which brings various functional capabilities to this tissue. Also, muscle fibers are able to regulate their phenotypic properties in response to different functional needs. Types of muscle fibers can be identified according to the difference in their structural and functional properties. The difference between muscle fibers is related to actin and myosin contractile membranes. Actin participates in many cellular processes, including muscle contraction. Myosin is a type of molecular motor and converts the chemical energy released from ATP into mechanical energy. This energy production occurs through the ATP hydrolyzing enzyme present in the myosin heavy chain. The myosin heavy chain isoform determines the maximum speed and force of shortening. The difference in energy required for force production and the difference in ATP phosphorylation potential in different types of fast and slow fibers can be effective in changing MHC isoforms. It seems that sports activity can cause a change in MHC isoforms and then a change in the phenotype of the muscle fiber through some mechanisms. In this study, we investigate the effect of exercise on MHC isoforms. Introduction The muscular system works to control the movement of our body and internal organs. Muscle tissue contains muscle fibers. Myofibrils are composed of myofilaments called actin and myosin filaments, which are repeated in units called sarcomeres and are the main functional units for muscle contraction. In general, there are two types of muscle fibers: type I, which is slow, and type II, which is fast. Type II is also divided into two parts: type IIA (oxidative) and type IIX (glycolytic), which make up three main types of fibers. These fibers have relatively distinctive metabolic, contractile and motor unit properties. Actins form one of the three main components of the cell skeleton and play an essential role in cell shape and motility, intracellular transport, muscle contraction and organelle dynamics, among other things. The main role of this protein is in the mechanical power generation systems of muscles and other cells. Myosins are also a superfamily of movement proteins that are mostly known for their role in muscle contraction and in a wide range of other movement processes in eukaryotes. Energy production in myosin occurs through a number of ATP hydrolyzing enzymes (ATPase) present in the heavy chain of myosin (in the head region). The myosin heavy chain isoform determines the maximum shortening speed and force according to the cross-sectional area of each muscle fiber. It seems that muscle fibers have a limited ability to change from one type to another, and in the phase of change, the fibers express a higher proportion of myosin heavy chain isoform. The question that has been investigated in some researches is whether or not sports activity can cause changes in myosin heavy isoforms, followed by a change in the size of muscle fibers (Geeves, 2016).

Keywords : exercise intensity consumption macromolecules