Limiting Factor

Muscle size is limited to the number of muscle cells a person is born with, and the percentage of fast twitch fibers of those muscle cells. Fast twitch fibers are fueled by the glycogenic factors, while slow twitch fibers are fueled by oxidative factors. The more slow twitch fibers a person has the lesser the chance of the muscles becoming big and dense, whereas, a person with a higher percentage of fast twitch can build huge muscles. Muscle fiber type distribution is the deciding factor to how much muscle a person can pack on.

Also, muscle fiber types are distributed differently through the body. This explains why some folks have bigger legs and hips and a smaller upper body. They have a higher concentration of fast twitch fibers in the legs and hips and a higher concentration of slow twitch in the upper body.

Folks that have a high overall concentration of fast twitch muscle fibers are more prone to store large amounts of fat onto their frame. Because remember fast twitch fibers operate without oxygen and utilize sugar to contract, while slow twitch fibers use oxygen and fat to contract.

NOT KNOWING how to train according to your body makeup can cause adverse effects on your body composition.