Answer:Muscle growth or “skeletal muscle hypertrophy,” as it's called at science parties) is the result of a complex process that adds more myosin “filaments” to each muscle fiber. This makes the “engine” of the cell bigger and stronger over time. ... This process is called muscle protein synthesis, or MPS. Skeletal muscle is composed of thread-like myofibrils and sarcomeres that form a muscle fiber and are the basic units of contraction. The 650 skeletal muscles in the human body contract when they receive signals from motor neurons, which are triggered from a part of the cell called the sarcoplasmic reticulum.