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Strength loss after eccentric contractions is unaffected by creatine supplementation
G L Warren1, J M Fennessy, M L Millard-Stafford
1Department of Physical Therapy, Georgia State University, Atlanta 30303, USA. phtglw@langate.gsu.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|August 5, 2000
Summary
Dietary creatine supplementation did not prevent strength loss in mouse muscles after eccentric contractions. Increased muscle creatine levels did not alter torque reduction following exercise-induced muscle injury.
Area of Science:
- Exercise Physiology
- Muscle Biochemistry
Background:
- Eccentric contractions can cause significant muscle damage and strength loss.
- Creatine supplementation is known to increase muscle creatine stores.
Purpose of the Study:
- To investigate if dietary creatine supplementation affects in vivo strength loss in mouse muscles after eccentric contractions.
- To determine the impact of elevated muscle creatine concentration on muscle's resistance to exercise-induced injury.
Main Methods:
- Mice received diets with varying creatine levels (0, 0.5, 1%) for 14 days.
- Muscle strength (torque) was measured via electrically stimulated contractions before and after a bout of 150 eccentric contractions.
- Tibialis anterior muscle creatine concentration was analyzed.
Main Results:
- Creatine supplementation increased muscle creatine concentration by up to 12%.
- No significant difference in torque loss was observed between creatine-supplemented and control groups after eccentric contractions.
- Strength loss ranged from 46-58% for isometric and eccentric contractions, and up to 88% for high-velocity concentric contractions.
Conclusions:
- Dietary creatine supplementation does not protect against strength loss induced by eccentric contractions in mice.
- Elevated muscle creatine levels do not mitigate exercise-induced muscle damage or subsequent strength deficits.