Antioxidants and muscle growth in elderly : the effect of supplementation with vitamin C and E on muscle growth and maximal strength during 12 weeks of resistance exercise in eldery men
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INTRODUCTION: Supplementation with antioxidants could either facilitate or hamper adaptations to resistance exercise due to redox-sensitive signaling pathways that regulate protein synthesis. Thus, the aim of the present study was to investigate the effect supplementation with vitamin C and E on muscle growth and maximal strength during 12 weeks of resistance exercise in elderly men. METHODS: Thirty-four elderly males (60 – 81 years) were randomized to either an antioxidant group (N=17; 1000 mg of vitamin C and 235 mg of vitamin E per day) or a placebo group (N=17). Muscle growth was assessed as changes in lean mass with dual-energy X-ray absorptiometry and local muscle thickness with ultrasound imaging. Maximal strength was measured as one-repetition maximum (1RM). All participants following a supervised undulating periodized program 3 times/week. RESULTS: Total lean mass increased by 3.9% (95% confidence intervals 3.0-5.2) and 1.2% (0-3.6) in the placebo and antioxidant group, respectively; revealing larger gains in the placebo group (p=0.03). Similarly, results from the thickness of rectus femoris increased more in the placebo group (16.2% [12.8-24.1]) than in the antioxidant group (10.9% [9.8-13.5]; p=0.01). Changes in lean mass of trunk and arms, as well as muscle thickness of elbow flexors and vastus lateralis, did not differ significantly between groups. With no group differences, 1RM improved in the range of 15-21% in both groups (p<0.001). CONCLUSION: Supplementation with vitamin C and E had no positive effects on the adaptation to resistance exercise in elderly men, but seemed on the contrary to hinder muscle growth.
Masteroppgave i idrettsvitenskap - Universitetet i Agder 2013