Formation of skeletal muscle is called myogenesis. Precursor cells called myoblasts originate in the somitic mesoderm. Limb and abdominal muscles develop from myoblasts migrating out of somites, whereas back muscles develop from nonmigrating myoblasts. Multinucleated skeletal muscle cells are formed from fusion of mononu-cleated myoblasts into myotubes. Subsequent synthesis of contractile myofibrils and organization into sarcomeres within myotubes result in maturation into myofibers. Myogenesis occurs in a primary wave during embryonic development followed by a secondary wave during early fetal developments. Primary and secondary fibers are predisposed to form slow and fast contraction fibers, respectively. Innervation occurs concurrently with maturation of muscle fibers and subsequently plays an important role in survival and determination of myofiber type. Groups of myofibers separate into individual muscles surrounded by connective tissue as development continues. Myofiber number becomes fixed near birth, although additional myonuclei are added as the fibers enlarge. Nuclei are added to existing fibers by fusion of additional myoblasts called satellite cells. Myofibers grow in diameter by adding new circumferential contractile filaments and grow in length by adding new sarcomeres to the end of existing filaments. Postnatal development of contractile and metabolic properties involves sequential replacement of many fiber-type specific proteins within existing myofibers.

Guaranteed – Six Pack Abs in Six Weeks

Guaranteed – Six Pack Abs in Six Weeks

Before we start working on how to get six pack abs in six weeks, there should be clarity in our mind about the need for six abs. Ones' personality is the key to his interaction with others. How we look, increases our confidence and boost up our self esteem. It's just not a person’s own confidence that goes up, but the other people around him also have more confidence in a fit and a healthy person.

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