The intensity factor

It has been widely observed that men who engage in highly repetitive tasks, such as common laborers, long distance runners, and swimmers show little improvement in their muscular size or strength as a result of their efforts. Such tasks, being of low intensity by nature, do little to stimulate such an adaptive response.

Over a century ago it was discovered-and it has been verified and re-verified since then- that the specific stimulus responsible for inducing muscular growth beyond normal levels in human beings is related to intensity of effort. The closer to the percentage of effort gets to 100%, the greater the growth stimulation. High-intensity muscular contractions, therefore, are an absolute requirement for stimulating rapid, large scale increases in muscular size and strength. Because of the demanding nature of such training , its impossible to perform large number of nigh intensity contractions in any given workout. This means you can train hard, or you can train long, but you cannot train hard and long.

Properly defined, intensity refers to the percentage of possible momentary muscular effort being exerted. It only on the last rep of a set carried to a point of muscular failure that an individual is forced to exert 100% of his momentary ability.

Executing that last, almost impossible rep causes the body to dip into its reserve ability.

Since it has only a small amount of this reserve to draw upon before depletion occurs, the body protects itself from future assaults on its reserves by enlarging upon its existing ability through through the compensatory buildup of more muscle mass.

Only high-intensity training can force the body to resort to its reserve ability sufficiently stimulate an adaptive response. Repeating tasks that are well within your existing capacity will do nothing to spur growth. Ending a set before failure, just because an arbitrarily chosen number of reps has been completed, will not cause you to grow.

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