Nautilus North

By Dr. Ellington Darden
Director, Athletic Center of Atlanta, Atlanta, Georgia

Muscle and fat are two important essentials of the human body, yet they are two of the most misunderstood components, particularly when the subject of exercise is discussed.

The body contains three types of muscles: the voluntary or skeletal muscles, the involuntary muscles such as those of the digestive tract, and the heart muscle. In exercise we are primarily concerned with skeletal muscles, because when these muscles contract, the body moves. Movement potential is brought into action by over 434 skeletal muscles. They are composed of 250 million smaller units, the muscle fibers, and make up 40 per cent of the body weight of the typical male.

On the other hand, at least 20 percent of the average man’s body weight is in the form of fat, or adipose tissue. The major function of fat is the long-term storage of energy. Additional functions are to provide heat insulation and protection for the body and the inner organs. Fat, however, does not contribute to muscular contraction. In fact, fat between muscle fibers acts as a friction brake and can actually impede the normal, relatively frictionless movement of lean muscle fibers during exercise. Therefore, in the performance of most sports, muscles literally contribute everything, while fat contributes nothing. As a result, millions of dollars are spent each year by coaches and athletes on muscle-building and fat-reducing programs, most of which are worthless. And even if a program has merit, a large amount of the possible results are usually neglected or lost due to gross misconceptions about training.

Let us examine some of the questions asked most frequently by coaches and athletes concerning muscle and fat. Hopefully the answers to these questions will help eliminate some misconceptions and thus improve training programs.

Muscle growth consists of two parts. One, there must be growth stimulation within the body itself at the basic cellular level. After puberty, this is best accomplished by high-intensity exercise. Two, the proper nutrients must be available for the stimulated cells. Providing large amounts of nutrients, in excess of what the body requires, will not do anything to promote the growth of muscle fibers. The growth machinery within the cell must be turned on. Muscle stimulation must always precede nutrition. If a trainee has stimulated muscular growth by high-intensity exercise, then his muscles will grow on almost any reasonable diet. Actually, the chemical reactions inside a growing muscle are much more complicated than just exercising and eating. High-intensity muscular contraction results in the formation of a chemical called creatine. The creatine stimulates the muscle to form more myosin, one of the contraction proteins within the muscle fiber. Thus, contraction of the muscle fiber produces creatine, which in turn causes the muscle to form more myosin, which enables it to undergo stronger contractions. This in turn causes the production of more creating, and around we go again. Creatine has been identified as the messenger substance that turns on the RNA (ribonucleic acid) processing line to produce muscle growth. The RNA fibers within a specialized compartment of the cell literally act as an assembly line and hook together various combinations of amino acids, sometimes in combination with complex sugars and fats, to form different compounds that result in the increased size of certain muscle cells. Remember, a trainee must stimulate growth through high-intensity exercise, and then provide the proper nutrients.

2. What exactly is meant by
high-intensity exercise?

For our purposes, high-intensity exercise means the repetitive performance of a resistance movement that is carried to the point of momentary muscular failure. Generally, this means that one set of each exercise should be performed in strict style for approximately 10 repetitions. At least 8 repetitions should be performed and not more than 12. If a trainee cannot do 8 then the resistance is too heavy, and if he can perform more than 12 it is too light. The real key to this technique is pushing oneself, or being pushed by someone else, always to perform as many strict repetitions as possible. A set is considered finished when it is momentarily impossible to perform another full repetition. When a trainee can perform 12 repetitions, add a small amount of resistance (usually 5 or 10 pounds) and reduce the repetitions to 8. Try to add an additional repetition each training day. Always add weight when 12 or more repetitions can be executed in good form.

3. What is considered good form?

Good form requires that all the repetitions be executed in a slow, smooth style. No throwing or jerking movements should be used. And special attention should be given to lowering the resistance (eccentric contraction). Research shows that for building muscular size and strength, lowering the resistance is far more important than raising the resistance. As an example, if it takes 2 to 3 seconds to raise a weight, then it should take 4 to 5 seconds to lower that same weight. All in all, it should take a trainee at least one minute to complete a set of 10 repetitions in good form.

4. I recently read several articles concerning the pre-stretching of a muscle during exercise. Where does it fit into proper form?

Pre-stretching is involved when a muscle is pulled into a position of increased tension prior to the start of a contraction. When a muscle is pre-stretched, a neurological signal is sent to the brain that results in a higher percentage of that muscle being contracted. All athletes consciously and unconsciously use pre-stretching in some fashion to their advantage. Take the baseball hitter who back swings before hitting the ball, or the boxer who draws back his fist before a punch, or the shot-putter who gets that little dip right before he throws. Pre-stretching can also be used effectively in strength-training sessions. Practiced properly, a trainee will be able to handle heavier weights and thus bring into action a greater percentage of his muscle mass during each repetition. There is a thin line, however, between: 1) pre-stretching a muscle in the starting position of an exercise and following through with the repetition in the proper manner, and 2) pre-stretching a muscle in the starting position and throwing the resistance. The key points to remember are: pre-stretch -- move quickly -- and then slow down. In other words, the weight should be lowered from the contracted position in a controlled manner until the bar or resistance arm is about one inch from the position of full extension. At that point, there should be a very quick twitch or thrust. After the quick twitch, the movement should be slowed down in a controlled manner. The only time the bar or resistance arm should be moved quickly is during the first one-quarter to one-half of the raising (positive) part of the repetition. The last half of each repetition should always be performed smoothly.