Lactalbumin, Not Collagen, Augments Muscle Protein Synthesis with Aerobic Exercise

Introduction Protein ingestion and the ensuing hyperaminoacidemia stimulates skeletal muscle protein synthesis in the postexercise period. This response facilitates muscle remodeling, which is important during intensified training. The aim of this study was to determine whether supplementation with α-lactalbumin (LA), with high leucine and tryptophan contents, would improve responses to short periods of intensified aerobic training compared with supplementation with an isonitrogenous quantity of collagen peptides (CP). Methods Endurance-trained participants (5 male, 6 female, 24 ± 4 yr, V˙O2 = 53.2 ± 9.1 mL·kg−1·min−1, peak power output = 320 ± 48 W; means ± SD) consumed a controlled diet (1.0 g·kg−1·d−1 protein) and refrained from habitual training for 11 d while taking part in this double-blind randomized, crossover trial. The two intervention phases, which consisted of brief intensified training (4 × 4-min cycling intervals at 70% of peak power output on 3 consecutive days) combined with the ingestion of LA or CP supplements after exercise (20 g) and before sleep (40 g), were separated by 4 d of washout without protein supplementation (i.e., the control phase). In response to each phase, myofibrillar (MyoPS), sarcoplasmic protein synthesis (SarcPS) rates (via 2H2O ingestion) and parameters of sleep quality were measured. Results LA ingestion increased plasma leucine (P
Source: Medicine and Science in Sports and Exercise - Category: Sports Medicine Tags: APPLIED SCIENCES Source Type: research