Muscle fibers need to increase in size for muscle building to be evident. This is done through the process called “hypertrophy” which could be done by increasing the volume of the sarcoplasm, increasing the amount of actin and myosin in the myofibrils and increasing the level of the satellite cells that are incorporated into the muscle fibers.

These satellite cells get their signal to fuse themselves into the existing muscle fibers when hormones for muscle growth leak out of a muscle fiber. They leak out through holes from the muscle fibers. These holes are created through intense training in the gym when you flex your muscles. So, flexing your muscles mean more “satellite cells” are incorporated into your existing muscles and that make you stronger and bigger.

Aside from exercise, your body won’t have the capability to build up your muscle building existing muscles without the availability of amino acids. While exercise enables the creation of more actin and myosin, the absence of amino acids will not make this creation of these two proteins possible.