This investigation evaluated the effects of oral β-Hydroxy-β-Methylbutyrate (HMB) supplementation on training responses in resistance-trained male athletes who were randomly administered HMB in standard encapsulation (SH), HMB in time release capsule (TRH), or placebo (P) in a double-blind fashion. Subjects ingested 3 g · day−1 of HMB or placebo for 6 weeks. Tests were conducted pre-supplementation and following 3 and 6 weeks of supplementation. The testing battery assessed body mass, body composition (using dual energy x-ray absorptiometry), and 3-repetition maximum isoinertial strength, plus biochemical parameters, including markers of muscle damage and muscle protein turnover. While the training and dietary intervention of the investigation resulted in significant strength gains (p < .001) and an increase in total lean mass (p = .01), HMB administration had no influence on these variables. Likewise, biochemical markers of muscle protein turnover and muscle damage were also unaffected by HMB supplementation. The data indicate that 6 weeks of HMB supplementation in either SH or TRH form does not influence changes in strength and body composition in response to resistance training in strength-trained athletes.
Gary Slater, David Jenkins, Peter Logan, Hamilton Lee, Matthew Vukovich, John A. Rathmacher and Allan G. Hahn
Cédric R.H. Lamboley, Donald Royer and Isabelle J. Dionne
The aim of this study was to determine the effects of oral β-hydroxy-β-methylbutyrate (HMB) supplementation (3 g/d) on selected components of aerobic performance and body composition of active college students. Subjects were randomly assigned to either an HMB (n = 8) or a placebo (PLA) group (n = 8) for a 5-wk supplementation period during which they underwent interval training 3 times a week on a treadmill. Aerobic-performance components were measured using a respiratory-gas analyzer. Body composition was determined using dual-energy X-ray absorptiometry. After the intervention, there were significant differences (P < 0.05) between the 2 groups in gains in maximal oxygen consumption (+8.4% for PLA and +15.5% for HMB) and in respiratory-compensation point (+8.6% for PLA and +13.4% for HMB). Regarding body composition, there were no significant differences. The authors concluded that HMB supplementation positively affects selected components of aerobic performance in active college students.
Douglas Paddon-Jones, Andrew Keech and David Jenkins
We examined the effects of short-term β-hydroxy-β-methylbutyrate (HMB) supplementation on symptoms of muscle damage following an acute bout of eccentric exercise.
Non-resistance trained subjects were randomly assigned to a HMB supplement group (HMB, 40mg/kg body weight/day, n = 8) or placebo group (CON, n = 9). Supplementation commenced 6 days prior to a bout of 24 maximal isokinetic eccentric contractions of the elbow flexors and continued throughout post-testing. Muscle soreness, upper arm girth, and torque measures were assessed pre-exercise, 15 min post-exercise, and 1,2,3, 4,7, and 10 days post-exercise.
No pre-test differences between HMB and CON groups were identified, and both performed a similar amount of eccentric work during the main eccentric exercise bout (p > .05). HMB supplementation had no effect on swelling, muscle soreness, or torque following the damaging eccentric exercise bout (p > .05).
Compared to a placebo condition, short-term supplementation with 40mg/kg body weight/day of HMB had no beneficial effect on a range of symptoms associated with eccentric muscle damage. If HMB can produce an ergogenic response, a longer pre-exercise supplementation period may be necessary.
Aline C. Tritto, Salomão Bueno, Rosa M.P. Rodrigues, Bruno Gualano, Hamilton Roschel and Guilherme G. Artioli
β-Hydroxy-β-methylbutyrate (HMB) exhibits anabolic and anticatabolic actions in skeletal muscle ( Wilkinson et al., 2013 ). However, studies examining HMB supplementation and resistance training have reported mixed results ( Jówko et al., 2001 ; Kreider et al., 1999 ; O’Connor & Crowe, 2007
Amy J. Hector and Stuart M. Phillips
-active young men, 3.42 g/day of free acid HMB ingestion was shown to stimulate MPS, although to a lesser extent than 3.42 g/day of leucine ingestion, and attenuated MPB ( Wilkinson et al., 2013 ). Another study found improvements in LBM gains and fat mass loss following 12 weeks of HMB supplementation in
Eric S. Rawson, Mary P. Miles and D. Enette Larson-Meyer
protein breakdown. The effects of HMB supplementation on markers of muscle damage and resistance training adaptations in lean mass and strength have been well reviewed ( Fitschen, Wilson, Wilson, & Wilund, 2013 ; Molfino, Gioia, Rossi Fanelli, & Muscaritoli, 2013 ; Zanchi et al., 2011 ). While early
Ronald J. Maughan, Louise M. Burke, Jiri Dvorak, D. Enette Larson-Meyer, Peter Peeling, Stuart M. Phillips, Eric S. Rawson, Neil P. Walsh, Ina Garthe, Hans Geyer, Romain Meeusen, Luc van Loon, Susan M. Shirreffs, Lawrence L. Spriet, Mark Stuart, Alan Vernec, Kevin Currell, Vidya M. Ali, Richard G.M. Budgett, Arne Ljungqvist, Margo Mountjoy, Yannis Pitsiladis, Torbjørn Soligard, Uğur Erdener and Lars Engebretsen
described in older adults following 10 days of bed rest ( Deutz et al., 2013 ). Benefits of HMB supplementation could most likely be obtained from normal dietary protein or whole protein supplements ( Wilkinson et al., 2013 ), so HMB supplements may not be more effective than adhering to the current protein