Effects of Whey Protein Supplementation with Hydrolyzed Collagen Associated with 12 Weeks of Resistance Training on Body Composition, Blood Biomarkers and Muscle Strength in Elderly Women

his two-arm randomized, double-blind, placebo-controlled design was carried out over a period of 17 weeks. At the beginning of the experiment, two weeks and at the end three weeks were allocated for evaluations consisting of anthropometric (weeks 2 and 16), body composition (weeks 2 and 16), one repetition maximum tests (weeks 1 and 15), functional capacity tests (weeks 1 and 15), blood samples (weeks 2 and 16), magnetic ressonance imaging (weeks 2 and 17) and dietary intake measurements (weeks 1 and 15). The anthropometric, body composition, blood samples and dietary intake measurements were carried out in a temperature-controlled room (22-24 °C), and the RT sessions were conducted at the university training facility.

Recruitment was carried out through newspapers, radio advertising, and home delivery of leaflets in the central area and residential neighborhoods. All participants completed health history and physical activity questionnaires and were included in the study if they met the following inclusion criteria: 60 years old or more, physically independent, free from cardiac or orthopedic dysfunction that would prevent them from performing the prescribed exercise or exercise testing associated with the study, not receiving hormonal replacement therapy, and completed a previous 8-week RT programParticipants underwent a diagnostic graded exercise stress test with a 12-lead electrocardiogram reviewed by a cardiologist and were released with no restrictions for participation in this investigation.

A blinded researcher was responsible for generating random numbers for participant allocation. Both groups were submitted to the same RT program and all participants completed the experiment. Written informed consent was obtained from all participants after a detailed description of investigation procedures was provided. This investigation was conducted according to the Declaration of Helsinki and was approved by the local University Ethics Committee The Shapiro Wilk test will be used to test data distribution. Data will be presented as means, standard deviation, and z-score. The student's independent t-test and chi-square test were will be used to compare groups regarding the general characteristics and clinical/medical history (categorical variables). Two-way analysis of variance (ANOVA) for repeated measures will be used to assess between group comparisons. The effect size (ES) will be calculated to verify the magnitude of the differences by Cohen's d, where an ES of 0.20-0.49 will be considered as small, 0.50-0.79 as moderate, and ≥ 0.80 as large(41). The Z-score of the percentage changes (from pre- to post-training) of the raw data for each parameter will be calculated, as well as a total Z-score, derived from all the components. To verify the differences between groups in total Z-scores, an independent T test will be also applied. For all statistical analyses, significance was accepted at P < 0.05. The data will be analyzed using SPSS software version 20.0 (SPSS, Inc., Chicago, IL, USA).