Glutamine Supplementation in Recovery From Eccentric Exercise Attenuates Strength Loss and Muscle Soreness

The purpose of this study was to examine the effect of glutamine supplementation on indices of recovery following eccentric exercise. In a randomized single-blind placebo-controlled design, 15 physically active males (mean age, 21 ± 1.5 years; mean height, 1.81 ± 0.07 m; mean body mass, 78.4 ± 9.2 kg) were assigned to a control or glutamine intervention group. Each participant performed 100 drop jumps from 0.6m followed by ingestion of 0.3 g · kg−1 body mass of maltodextrin mixed with 750 mL of distilled water and lemon flavoring (Control) or with an additional 0.3 g · kg−1 L-glutamine (Glutamine) at 0, 24, 48, and 72 hours post-exercise. Knee-extensor concentric peak torque at angular velocities of 0.52 and 3.14 rad · s−1, perceived muscle soreness, and plasma creatine kinase activity were measured at 0, 1, 24, 48, 72, and 96 hours post-exercise. L-glutamine supplementation resulted in a greater preservation of peak torque over the 96-hour measurement period at both 0.52 rad · s−1 (Control, 75 ± 16%; Glutamine, 85 ± 15% of pre-exercise values, p = 0.03) and 3.14 rad · s−1 (Control, 79 ± 16%; Glutamine, 90 ± 12%, p = 0.01). Muscle soreness was significantly lower over 96 hours with L-glutamine supplementation (Control, 4.6 ± 2.5 units; Glutamine, 3.6 ± 2.5 units, p = 0.03). L-glutamine supplementation did not affect the magnitude or temporal nature of the creatine kinase response. As a therapeutic intervention, glutamine supplementation was effective in attenuating strength loss and muscle soreness following eccentric exercise-induced muscle damage.