Urbanski, R. L., Foy, S. F., Vincent, W. J., & Yaspelkis, B. B. (1999). Creatine supplementation differentially affects maximal isometric strength and time to fatigue in large and small muscle groups. International Journal of Sport Nutrition, 9(2), 136-145.

Active, but untrained, college males (N = 10) ingested creatine monohydrate (5 gm Cr + 3 gm dextrose) or a placebo of dextrose (7 gm) four times a day for five days. Performance assessments consisted of maximal and three repeated submaximal bouts of isometric knee extension and handgrip exercises.

Cr ingestion significantly increased maximal isometric strength but not handgrip strength. Time to fatigue was increased in both sites under the Cr condition.

These results suggest that Cr ingestion works more effectively with large muscle groups, in that it improves both strength and time to fatigue, than in small muscle groups, such as the hand. This could be influenced by the hand muscles being closer to ceiling strength than the knee extensors and therefore have less room for improvement.

Implication. Creatine supplementation is less likely to affect strength when muscles are near maximal strength but resistance to fatigue can be improved in muscles that are not substantially trained before testing.

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