Muscle Training Program, Part 2

Our muscle training program begins with a little background on how our muscles work.

The muscles of our bodies allow us to move freely. Using electrochemical energy generated by the amazing intracellular power plants called mitochondrea, muscle fibers possess the unique ability to contract. The muscular contractions exert a force and the force creates movement. Whether it is the tiny movements of our eyelids or the massive action of an Olympic weight lifter, our active life as humans depends upon our muscles.

Skeletal, sometimes called voluntary, muscle makes up about 40 percent of our body weight. The cardiac muscle of the heart and the smooth muscle of the abdomen makes up another 10 percent. There are 430 defferent skeletal muscles in the human body, ranging in size from the tiny muscles that control the tension of the ear drums to the vast muscles of the thigh and back.

At the microscopic level, muscles contain bundles of specific contractile proteins organized into larger groupings called fibers. When the muscle fibers are stimulated by the nerves that control them, a series of electrical and chemical changes occur in the muscle fibers causing them to shorten and exert a force. This force is transmitted to the bones of the skeleton through the tendons. These muscles contract, exerting a force on the tendons which then moves the skeletal bones.

All movement occurs around the joints. For example, when the biceps muscle group of the upper arm contracts, it causes the arm to bend at the elbow. To straighten the arm, the biceps relax and the muscles of the outer arm, the triceps, contract. The alternating contraction and relaxation of opposing muscle groups around the joints creates the complex movement of life.

Skeletal muscle can be further subdivided into Type I, slow-twitch, and Type II, fast-twitch, fibers. Slow-twitch fibers, as the name implies, contract more slowly and for a more sustained period of time compared to their fast-twitch counterparts. They are important for maintaining muscle tone, body posture and account for the endurance aspects of movement. The fast-twitch fibers exert their force briefly before fatiguing and are important for generating forceful and powerful muscle activity. When we engage in endurance sports like running or swimming, slow-twitch fibers predominate. Sports involving strength and speed, like martial arts or the shot put, depend more on fast-twitch muscles. Short distance track events, like sprints, involve both types of fibers.

All skeletal muscle fibers have the ability to adapt to the workload placed upon them. Slow-twitch fibers adapt by increasing their ability to generate energy and sustain movement, while fast-twitch fibers adapt by increasing their size so they can develop more force and power. Bodybuilders use this characteristic adaptation of fast-twitch fibers, called hypertrophy, to produce the seemingly amazing muscle development results seen in popular fitness magazines.

Although the professional stars of bodybuilding, as in most sports, are genetically gifted individuals deeply committed to their training and their sport, virtually anyone can improve muscularity by following the basic principles discussed in this series and by training in a consistent and dedicated way.

Moment by moment the muscles of the body are in a dynamic process of remodeling. The body tears them down and builds them up again. The process of tearing down is called catabolism. The process of building up is called anabolism. For your muscle mass to increase, your body's anabolic processes must outweigh the catabolic processes. Reducing catabolism by getting adequate rest and nutrition, controlling stress and eliminating bad habits like excessive alcohol and tobacco use, is essential to optimizing muscle growth. Overtraining also increases catabolic stress and impedes growth. Overtraining is one of the most common training mistakes and is discussed at length later in the series.

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