Resistance training & beta-hydroxy-beta-methylbutyrate supplementation on hormones

Abstract

RESUMOIntroduction: In recent years, there was an increased interest on the effects of beta-hydroxy-beta-methylbutyrate (HMB) supplementation on skeletal muscle due to its anti-catabolic effects. Objectives: To investigate the effect of HMB supplementation on body composition, muscular strength and anabolic-catabolic hormones after resistance training. Methods: Twenty amateur male athletes were randomly assigned to supplement and control groups in a double-blind crossover design and participated in four weeks resistance training. Before and after the test period fasting blood samples were obtained to determine anabolic (the growth hormone and testosterone) and catabolic (cortisol) hormones, and fat mass, lean body mass (LBM) and muscular strength were measured. Dependent and independent t-tests were used to analyze data. Results: After the training period, there were no significant differences between the groups with respect to fat mass, LBM and anabolic-catabolic hormones. HMB supplementation resulted in a significantly greater strength gain (p≤0.05). Conclusion: Greater increase in strength for HMB group was not accompanied by body composition and basal circulating anabolic-catabolic hormonal changes. It seems that HMB supplementation may have beneficial effects on neurological adaptations of strength gain.Keywords: resistance training, hormones, body composition, dietary supplements, HMB, muscle strength. ABSTRACT Introduçao: Nos últimos anos, houve um aumento no interesse sobre os efeitos da suplementação de beta-hidroxi--beta-metilbutirato (HMB) no

Effects of β-Hydroxy-β-methylbutyrate-free Acid Supplementation on Strength, Power and Hormonal Adaptations Following Resistance Training

“…Changes in the resting GH, IGF-1 and TEST concentrations during resistance training have been inconsistent in men. On the other hand, elevated resting GH, IGF-1 and TEST concentrations have been reported in some studies [ 4 , 7 , 31 ], whereas several studies have shown no differences [ 32 , 33 ] or reductions [ 34 ]. To our knowledge, this was the first study that examined the effects of chronic HMB-FA supplementation on hormonal adaptations after resistance training; however, in an earlier study by Townsend et al [ 10 ], enhancement of GH and IGF-1 occurred only by acute ingestion of 1 g HMB-FA prior to a session of resistance exercise.…”

“…Therefore, amino acid supplementation can promote adaptations to resistance training via several mechanisms (e.g., promoting protein synthesis, attenuating muscle damage and hormone adaptations) [ 6 ]. Because of the critical role of amino acids, recent studies have investigated the efficacy of β-Hydroxy-β-methylbutyrate (HMB) supplementation for promoting resistance exercise adaptations [ 7 , 8 ]. HMB is a metabolite of the amino acid leucine, a potent stimulus of translation initiation and protein synthesis [ 8 ], and several studies indicated that HMB could enhance muscle size and strength performance [ 7 , 9 ], elevate anabolic hormones [ 10 ] and attenuate catabolic hormones [ 11 ] following resistance exercise.…”

“…Because of the critical role of amino acids, recent studies have investigated the efficacy of β-Hydroxy-β-methylbutyrate (HMB) supplementation for promoting resistance exercise adaptations [ 7 , 8 ]. HMB is a metabolite of the amino acid leucine, a potent stimulus of translation initiation and protein synthesis [ 8 ], and several studies indicated that HMB could enhance muscle size and strength performance [ 7 , 9 ], elevate anabolic hormones [ 10 ] and attenuate catabolic hormones [ 11 ] following resistance exercise. In addition, HMB increased phosphorylation activity of the mammalian inhibitor target of rapamycin (mTOR) pathway and mTOR initiation factors in the muscle with reduction of the ubiquitin-proteasome proteolysis pathway in humans, resulting in preservation of lean body mass [ 12 , 13 ].…”

“…In addition, HMB increased phosphorylation activity of the mammalian inhibitor target of rapamycin (mTOR) pathway and mTOR initiation factors in the muscle with reduction of the ubiquitin-proteasome proteolysis pathway in humans, resulting in preservation of lean body mass [ 12 , 13 ]. In relation to chronic supplementation with HMB, several research groups in this area reported no change [ 9 , 13 ] and increases [ 7 ] in strength and power during a resistance training program.…”

“…To date, the majority of researchers utilized supplementation of commercially available calcium salt form of HMB (HMB-Ca) [ 7 , 11 , 12 , 13 ] and research studies in this area reported conflicting results when supplemented with HMB-Ca during a resistance training intervention. However, a new free form of HMB (HMB-FA) has been shown to have a more rapid and higher bioavailability compared to HMB-Ca [ 14 , 15 ].…”