The effect of L-Arginine supplementation on Delayed Onset Muscle Soreness (DOMS) after eccentric heavy exercise

Introduction: L-Arginine supplementation improves antioxidant defenses through LArginine/ nitric oxide pathways. This investigation assesses the influences of acuteLArginine supplementation on selected markers of delayed onset muscle soreness (DOMS) after one by one heavy eccentric exercise in healthy young females. Methods: Twelve healthy young females students of the University of Mohaghegh-Ardabili voluntarily participated in a double-blind randomized-controlled crossover trial to estimate the effects of 3g L-Arginine oral supplementation versus placebo (3g glucose) following an unaccustomed heavy eccentric exercise. L-Arginine (ARG) or placebo (PLC) was taken immediately after squat exercise, separated by 10day washout. Measurements were conducted at baseline, 24, and 48h after exercise comprising: (a) TAC (b) CK (c) LDH (d) Visual Analogue Scale (VAS) (e) Range of Motion (ROM) of both knees (f) Edema of both thighs. For data analysis software SPSS version 20 was used. To analysis the data, analysis of variance with repeated measure was used. Results: TAC significantly increased 48h after exercise compared with the pre-exercise just in ARG group (P 0.05). CK and LDH significantly enhanced 24, and 48h after exercise only in the PLC group (P 0.05). VAS and edema increased 24, and 48h after exercise compared with the pre-exercise in both groups (P 0.05). Moreover, ROM decreased in both groups 24, and 48h after exercise compared with the pre-exercise (P 0.05). There were no between-group differences in any time series (P 0.05). Conclusion: The findings of this study suggest that acute supplementation of ARG after heavy eccentric exercise may alleviate muscle damage through promoting the antioxidant capacity, protein synthesis, or decrease of lactate accumulation.