Impact of protein supplementation on muscle recovery after exercise-induced muscle soreness
We investigated whether protein (PRO [0.4g/kg]) vs. carbohydrate (CHO [0.4g/kg]) vs. placebo nutrition supplements would alleviate muscle soreness when consumed immediately after eccentric exercise in 21 untrained men aged 18-30 years. During this double-blind randomized block study design, each subject completed three, 3-day trials (separated by ≥2 weeks), identical except for treatment, with each serving as his own control. Trials began with a bout of right leg eccentric exercise (Biodex), followed directly by treatment. At 0 (baseline), 24, and 48 hours, data were collected: creatine phosphokinase (CPK) from pre-exercise blood samples, subjective muscle soreness questions, and strength tests (power, torque, work). ANOVA indicated that exercise caused mild muscle damage, evidenced by an overall day effect (p≤0.0001) for muscle soreness, with the lowest median values (0 to 10 scale) on day 1 (0.7), increasing (p≤0.0001) on day 2 (3.2), and remaining elevated on day 3 (3.4). We also noted an overall day effect (p≤0.0001) for CPK, with lowest median values (U/L) on day 1 (136), increasing (p≤0.0001) on day 2 (235), and remaining elevated on day 3 (189). ANOVA revealed no significant treatment effect on indicators of soreness or damage during recovery. Our results indicated that a PRO or CHO supplement after exercise causing mild muscle damage did not facilitate muscle recovery in adequately nourished, healthy young men.