Abstract

The effects of 6-week programs of isotonic and isometric exercises were observed in 49 male subjects. The 24 subjects who performed isotonic exercises showed greater gains in strength and hypertrophy than did the 25 subjects who exercised isometrically. Tests of strength were performed both in a position similar to that in which subjects were exercised and also in an unfamiliar position. In addition, tests were used which employed the musculature in a familiar and in an unfamiliar manner. Whereas subjects showed strength gains in the tests when muscles were employed in a familiar way, little or no gain in strength was observed when unfamiliar procedures were employed. The findings suggest that the higher scores in strength tests resulting from the exercise programs reflected largely the acquisition of skill.

Submitted on September 7, 1956