Amino Acid Leucine No Aid to Muscle Recovery

NORMAN, Okla.—Adding leucine to a pre- and post-exercise carbohydrate beverage does not provide benefit on muscle recovery after resistance exercise, according to a new study (J Strength Cond Res. 2010;24(8):2211-19. DOI: 10.1519/JSC.0b013e3181dc3a10). Leucine is an essential amino acid that plays a role in muscle protein synthesis. Researchers in the Department of Health and Exercise Science at the University of Oklahoma, Norman, recruited resistance-trained men (n=17) and women (n=3) for their study looking at the impact of supplemental leucine on selected markers of muscle damage, delayed-onset muscle soreness (DOMS) and squat performance after lower-body resistance training (six sets of squats to fatigue). Subjects consumed a carbohydrate beverage with or without 22.5 mg/kg-1 of leucine 30 minutes before and immediately after squat exercise, in a randomized, double blind fashion. The subjects repeated the exercise at 72 hours to test recovery.

There were no differences between groups for squat performance either initially or after 72 hours. Further, the added leucine did not significantly decrease serum creatine kinase (CK) or lactate dehydrogenase (LDH) activity—markers of skeletal muscle damage—nor did it affect muscle soreness.