The main aim of the project is the assessment of the effects of 3 weeks supplementation with two doses of betaine (2.5 g∙d-1 and 5 g∙d-1) on anaerobic capacity, CrossFit performance, body composition, and betaine metabolism in a group of male speed-strength trained athletes.~The study is designed as a double-blind, randomized, placebo-controlled crossover trial. 80 male participants will be divided randomly into two parallel groups: one receiving 2.5 g·d-1 betaine and the second receiving 5 g·d-1 betaine. In both experimental groups participants will receive both betaine supplement or placebo in a random order. The supplementation periods (betaine and placebo) will last for three weeks each and will be separated by a 3-week washout. The participants will attend four study meetings at the Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences, Poland. Food intake before and during the intervention will be assessed with the use of food diary and intakes of macro- and micronutrients will be calculated with the use of Dieta 5.0 software. On each visit Wingate ergocycling test will be performed, body composition will be measured and blood samples will be taken. The same day in the afternoon/evening hours the Fight Gone Bad (FGB) test will be performed. Body composition will be assessed based on air displacement plethysmography technology using the Bod Pod®. Moreover, total body water content will be analyzed by bioelectric impedance with the use of a BIA 101S analyzer. Anaerobic capacity will be assessed using the classical Wingate test on a cycloergometer. In order to assess CrossFit performance the FGB test will be performed. In blood samples the investigators plan to analyze concentrations of: lipoproteins and triglycerides (biochemical analyzer), betaine (LC-MS method), amino acid profile (LC-MS method), and testosterone (ELISA). MTHFR genotype will be analyzed with using a PCR-RFLP method. Data will be analyzed using the STATISTICA 12 software program.
The study is aimed at assessing the influence of two betaine doses (2.5 g∙d-1 and 5 g∙d-1) supplemented for three weeks in a group of speed-strength trained athletes on anaerobic capacity in Wingate test, performance in CrossFit-like exercise test - Fight Gone Bad, alterations in body compositions and total body water.