Fifty years ago, the physiology of muscle hypertrophy (growth) was a mystery. A common perception among many athletes and coaches was that training turns fat into muscle. Scientists didn’t have the tools to study muscle growth; the technology wasn’t available. That changed in the 1960s and ‘70s- the development of the electron microscope, muscle biopsy techniques and radioactive tracers allowed scientists to look inside the muscle. Now, we know that increasing muscle strength and size involves turning on special genes to manufacture new muscle tissue and training the nervous system to better coordinate and regulate muscle force.
We understand how muscles get larger and have effective techniques for gaining muscle mass with less risk of injury and over-training.How the Body Builds MuscleAbout 20 percent of muscle is protein- the rest is water. Muscles are made up of individual muscle cells connected in bundles. Muscle fibers contain sub-units called myofibrils that are further divided into myofilaments (actin and myosin) that slide across each other to cause muscle contraction. One of the goals of your weight-training program should be to increase the size of muscle fibers by increasing the number of myofibrils, a process called hypertrophy. Most studies show that weight training increases fiber size- not fiber number. Muscle size and strength are directly related- the larger the muscle, the greater its strength.