Effects of Whey Protein and Collagen Supplementation on Muscle Mass and Function During Training in Young Adults

The purpose of this study will be to investigate the effects of whey protein vs. leucine-matched collagen supplementation on muscle mass and function after a 10-wk resistance training program. Initially, all participants will be submitted for a 2-wk familiarization period, and then randomized into two groups (N = 11 / group): whey protein group and leucine-matched collagen group. The following variables will be assessed from pre-to post-training: anthropometric, muscle thickness from vastus lateralis and biceps brachii muscles using ultrasound, training load, mean power and peak torque for unilateral arm flexion exercise using a isokinetic dynamometer, countermovement vertical jump, nutritional intake, and testosterone-to-cortisol ratio . Shapiro-Wilk and Levine tests will be used to test the normality and homogeneity of the measurements, respectively. Two-way ANOVA (group x time) tests for repeated measures will be performed to assess changes over time and between groups for all dependent variables. Violation of sphericity will adjust using Greenhouse- Geyser correction. The Bonferroni post-hoc test will detect specific differences between groups. When appropriate, the percentage of change (∆%) will be reported according to the following equation: ∆% = [(pre-average post average) / pre-average mean] × 100. Values will be express as mean ± standard deviation. O significance level α will be 0.05.