Journal Article

The efficacy of a β-hydroxy-β-methylbutyrate supplementation on physical capacity, body composition and biochemical markers in elite rowers: a randomised, double-blind, placebo-controlled crossover study

Jeszka, Jan, Durkalec-Michalski, Krzysztof

2015

Overview

Background β-hydroxy-β-methylbutyric acid (HMB) is an interesting supplement in sports. However, literature sources present a limited number of studies that verify the efficacy of HMB intake over a longer time period among endurance athletes. For this reason, the aim of this study was to assess the effect of HMB supplementation on physical capacity, body composition and levels of biochemical markers in rowers. Methods Sixteen elite male rowers were administered a 12-week HMB supplementation (3×1 g HMB  · day −1 ) and placebo administration (PLA) following the model of a randomised, placebo controlled, double-blind crossover study with a 10 days washout period. Over the course of the experiment, aerobic (maximal oxygen uptake, ventilatory threshold) and anaerobic (anaerobic power indices) capacity were determined, while analyses were conducted on body composition as well as levels of creatine kinase, lactate dehydrogenase, testosterone, cortisol and the T/C ratio. A normal distribution of variables was tested using the paired 2-tailed t-tests; the Mann–Whitney U -test or the Wilcoxon-signed rank test were applied for non-normally distributed variables. Results Following HMB supplementation, V ˙ O 2 max increased (+2.7 mL · min −1  · kg −1 ) significantly ( p  < 0.001) in comparison to its reduction after PLA (−1.0 mL · min −1  · kg −1 ). In turn, at the ventilatory threshold, a longer time was required to reach this point (+1.2 min HMB vs. −0.2 min PLA , p  = 0.012), while threshold load (+0.42 W · kg −1 HMB vs. −0.06 W · kg −1 PLA , p  = 0.002) and threshold heart rate (+9 bpm HMB vs. +1 bpm PLA , p  < 0.001) increased. After HMB supplementation, fat mass decreased (−0.9 kg HMB vs. +0.8 kg PLA , p  = 0.03). In relation to the initial values after HMB supplementation, the refusal time to continue in the progressive test was extended ( p  = 0.04), maximum load ( p  = 0.04) and anaerobic peak power ( p  = 0.02) increased. However, in relation to the placebo, no differences were observed in anaerobic adaptation or blood marker levels. Conclusions The results indicate that HMB intake in endurance training has an advantageous effect on the increase in aerobic capacity and the reduction of fat mass. It may also stimulate an increase in peak anaerobic power, while it seems to have no effect on other indices of anaerobic adaptation and levels of investigated markers in the blood.

• Publisher: BioMed Central,Taylor & Francis Ltd
• Subject: Adolescent / athletes / biomarkers / Biomarkers - blood / blood / body composition / Body Composition - drug effects / Body Mass Index / Clinical Nutrition / cortisol / creatine kinase / Creatine Kinase - blood / Cross-Over Studies / Dietary Supplements / Double-Blind Method / heart rate / Humans / L-Lactate Dehydrogenase - blood / lactate dehydrogenase / Male / males / Medicine / Medicine & Public Health / normal distribution / oxygen / Oxygen Consumption / Physical Endurance - drug effects / placebos / Research Article / sports / Sports Medicine / sports nutrition / t-test / testosterone / Valerates - administration & dosage / Young Adult