The purpose of this study was to investigate the effects of supplementation of whey protein (WP) versus leucine-matched collagen peptides (CP) on muscle thickness MT and performance after a resistance training (RT) program in young adults. Twenty-two healthy untrained participants were randomly assigned to either a WP (n = 11) or leucine-matched CP (n = 11) group and then submitted to a supervised 10-week RT program (3 days/week). The groups were supplemented with an equivalent amount of WP (35 g, containing 3.0 g of leucine) and CP (35 g, containing 1.0 g of leucine and 2.0 g of free leucine) during the intervention period (after each workout and in the evening on nontraining days). MT of the vastus lateralis and biceps brachii, isokinetic peak torque and mean power output of the elbow flexors, and peak power output of the lower body were assessed before and after the RT program. The WP group experienced a greater (interaction, p < .05) increase in the vastus lateralis (effect size, WP = 0.68 vs. CP = 0.38; % Δ, WP = 8.4 ± 2.5 vs. CP = 5.6 ± 2.6%) and biceps brachii muscle thickness (effect size, WP = 0.61 vs. CP = 0.35; % , WP = 10.1 ± 3.8 vs. CP = 6.0 ± 3.2%), with a similar increase in muscle performance (peak torque, mean power output, and peak power output) between groups (time p < .05). Supplementation with WP was superior to leucine content-matched CP supplementation in increasing muscle size, but not strength and power, after a 10-week RT program in young adults.

本研究的目的是研究补充乳清蛋白 (WP) 与亮氨酸匹配的胶原蛋白肽 (CP) 对肌肉厚度 MT 和年轻人阻力训练 (RT) 计划后表现的影响。22名未经训练的健康参与者被随机分配到 WP（n  = 11）或亮氨酸匹配的 CP（n = 11) 组，然后提交到有监督的 10 周 RT 计划（3 天/周）。在干预期间（每次锻炼后和晚上），各组补充等量的 WP（35 g，含 3.0 g 亮氨酸）和 CP（35 g，含 1.0 g 亮氨酸和 2.0 g 游离亮氨酸）在非训练日）。在 RT 程序之前和之后评估股外侧肌和肱二头肌的 MT、肘屈肌的等速峰值扭矩和平均功率输出以及下半身的峰值功率输出。WP 组经历了更大的（互动，p < .05) 增加股外侧肌（效应大小，WP = 0.68 vs. CP = 0.38；% Δ，WP = 8.4 ± 2.5 vs. CP = 5.6 ± 2.6%）和肱二头肌厚度（效应大小，WP = 0.61 vs. CP = 0.35；% , WP = 10.1 ± 3.8 vs. CP = 6.0 ± 3.2%），组间肌肉性能（峰值扭矩、平均功率输出和峰值功率输出）增加相似（时间p  < .05)。在年轻人中进行了 10 周的 RT 计划后，补充 WP 在增加肌肉大小方面优于补充亮氨酸含量匹配的 CP，但不是力量和力量。