Effect of antioxidant vitamin supplementation on muscle function after eccentric exercise

Area of Science:

• Exercise Physiology
• Nutritional Biochemistry
• Muscle Biology

Background:

• Eccentric exercise can induce muscle damage, leading to impaired muscle contractile function.
• Antioxidant vitamins are hypothesized to mitigate exercise-induced muscle damage.
• Previous research on antioxidant supplementation and muscle recovery remains inconclusive.

Purpose of the Study:

• To investigate the effects of antioxidant vitamin E and vitamin C supplementation on muscle contractile function after eccentric exercise.
• To determine if vitamin C or vitamin E supplementation can accelerate recovery of muscle function post-exercise.

Main Methods:

• A double-blind study involving 24 physically active subjects.
• Supplementation with placebo, vitamin E (400 mg), or vitamin C (400 mg) daily for 21 days prior to and 7 days after eccentric exercise (box-stepping).
• Assessment of triceps surae muscle contractile function via maximal voluntary contraction (MVC) and 20/50 Hz tetanic stimulation ratio before, immediately after, and during 7 days of recovery.

Main Results:

• Eccentric exercise significantly reduced MVC and the 20/50 Hz tetanic tension ratio.
• Vitamin C supplementation resulted in greater MVC recovery within 24 hours post-exercise compared to placebo.
• Vitamin C supplementation significantly attenuated the decrease in the 20/50 Hz tetanic tension ratio post-exercise and during early recovery, unlike vitamin E.

Conclusions:

• Prior vitamin C supplementation may offer a protective effect against eccentric exercise-induced muscle damage.
• Vitamin C appears more effective than vitamin E in enhancing muscle function recovery following strenuous eccentric exercise.
• These findings suggest a potential role for vitamin C in sports nutrition strategies aimed at reducing exercise-induced muscle injury.