Voluntary Maximal Muscular Contraction

Voluntary maximal muscle contractions appear to be the most effective way to increase muscular strength (Fleck & Schott, 1985). The last repetition in a set carried to failure is a voluntary maximal contraction, even though the force it produces is not the maximal force possible during the whole set. Many resistance-training systems use sets to failure and/or repetition maximums (RMs) precisely to assure that voluntary maximal contractions — and the associated training effects — take place.

The need to perform voluntary maximal contractions is what is meant by "overloading" the muscle: the muscle must contract against a resistance it does not normally encounter. This process stimulates the physiological changes that increase the strength and size of the muscle. A later restatement in the source condenses this: the last repetition in a set to failure is a voluntary MMC; performing MMC is referred to as overloading the muscle, which stimulates the changes that increase strength and size.

• Voluntary maximal contractions = most effective stimulus for increasing strength.
• The final rep of a set to failure is a voluntary maximal contraction (though not the maximal force possible in the set).
• Sets to failure and RM loads are used to ensure maximal contractions occur.
• "Overloading" the muscle = making it contract against resistance it does not normally encounter.

• progressive-overload — this concept is the mechanism behind the overload principle.
• exhaustion-set — sets to exhaustion deliberately drive the muscle to a maximal contraction.
• forced-repetition — extends the set past failure with partner assistance.
• repetition-maximum — RM loading guarantees the set ends at a maximal effort.
• muscle-hypertrophy — the size/strength change stimulated.