The Efficacy Of Protein Supplementation On Attenuating Muscle Atrophy Following Disuse

Abstract

PURPOSE: The purpose of this study was to determine the effects of protein supplementation during muscular disuse in maintaining muscle cross-sectional area, lean mass, strength, and jump force in the collegiate population. METHODS: Two groups of healthy collegiate participants (n=14) underwent two weeks of unilateral lower limb suspension (ULLS), during which the control group consumed a normal diet (CON) and the treatment group (PRO) received an additional 75g/day of supplemental protein. Outcome measures included lean mass (LM) measured using DXA, muscle area (MA) of the lower leg using pQCT, isokinetic torque measurements using a Biodex ergometer, and force production during jumping using a portable force platform. Differences in the change of these outcome measurements from baseline to follow-up were compared between the treatment and control groups (group ∗ time interaction, controlling for baseline measurement). RESULTS: Daily protein intake for the treatment group (2.6±1.0 g/kg/d) was greater than the control group (1.5±1.1 g/kg/d). Daily caloric intake was not different between groups (3015±1098 kcal/day; Treatment 2772±432 kcal/day). MA decreased in both groups following ULLS with no differences between groups measured. However, there was a moderate difference in change between groups with the PRO maintaining their total LM (group∗time interaction, p=0.08) and leg LM (group∗time interaction, p=0.1) when compared to the CON. CONCLUSION: This study demonstrates a universal loss in lower leg muscle area muscle during a relatively short period of disuse. Additionally, there was evidence of a trend toward a positive effect of protein supplementation on lean mass maintenance during disuse. The results of this study serve as an important first step of identifying nutritional interventions to augment rehabilitation.