Effects of Whey Protein and Collagen Supplementation

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.

Inclusion criteria

• Men and women aged 18-35 years
• To be eutrophic (not overweight or obese)

Exclusion criteria

• To present a history of musculoskeletal disorders
• Be attending a systematized weight training program for at least six months
• To make use of medicines that could affect muscle function.
• To have used ergogenic supplements and anabolic steroids for at least six months before study
• To have restrictions for exercises practice considering Physical Activity Readiness Questionnaire (PAR-Q) responses.