To The Editor:
We have recently become aware of the article by Lowery et al. in J Strength Cond Res 30(7): 1843–1854, 2016 entitled “Interaction of Beta-Hydroxy-Beta-Methylbutyrate Free Acid and Adenosine Triphosphate on Muscle Mass, Strength, and Power in Resistance-Trained Individuals.” We have some thoughts regarding the Methods and Results sections of the article for the readership of JSCR to consider.
- Minimal difference values were not provided for body composition variables determined by DXA. Could the authors provide ICC's, along with the SD values for lean body mass (LBM) and fat mass (FM) so that minimal difference can be determined?
- The authors fail to provide any citation for location of ultrasonography for assessment of skeletal muscle hypertrophy.
- Were records kept for total training volume completed during the intervention for each group? Was volume and load equated across groups?
- We realize that one earlier study demonstrated similar findings as that of this study; however, the Kraemer et al. (1) study used less-trained subjects, as well as a multiingredient supplement containing HMB-Ca. This study also found significant elevations in postexercise testosterone levels, whereas this study did not. Could the authors expand on the potential mechanisms responsible for muscle growth (highlighting the form and dose of HMB used in this study compared with previous studies)?
- We are curious about the increase in LBM (8.5 kg) and significant decrease in FM observed in the resistance-trained population used. The increase in LBM is somewhat shocking, especially when compared with previous literature using HMB in athletic populations (2–4). Further explanation as to how or why these robust changes occurred would certainly benefit the reader. If no sound explanation can be made, could there have been possible errors with the DXA machine or how the data were analyzed/reported? This might help to explain why—for the most part—these authors are the only ones who have found such significant improvements in body composition after HMB and ATP supplementation (5,6).
Owing to inconsistencies in findings between this study and that of data previously published from other laboratories, we strongly encourage researchers to replicate this study in an attempt to discover comparable findings. Furthermore, the authors mention an increase in blood flow and/or an increase in training volume as possible mechanisms for muscle growth, but blood flow was not measured and training volume was not reported. We suggest future research aim to measure or track these variables to provide possible explanations for improvements in strength and body composition after HMB + ATP supplementation. In addition, we recommend measuring growth hormone and insulin-like growth factor to determine possible underlying mechanisms for the significant increases in LBM.
1. Kraemer WJ, Hatfield DL, Volek JS, Fragala MS, Vingren JL, Anderson JM, Spiering BA, Thomas GA, Ho JY, Quann EE, Izquierdo M, Hakkinen K, Maresh CM. Effects of amino acids supplement on physiological adaptations to resistance training. Med Sci Sports Exerc 41: 1111–1121, 2009.
2. Kreider RB, Ferreira M, Wilson M, Almada AL. Effects of calcium beta-hydroxy-beta-methylbutyrate (HMB) supplementation during resistance-training on markers of catabolism, body composition and strength. Int J Sports Med 20: 503–509, 1999.
3. Nissen S, Sharp R, Ray M, Rathmacher JA, Rice D, Fuller JC Jr, Connelly AS, Abumrad N. Effect of leucine metabolite beta-hydroxy-beta-methylbutyrate on muscle metabolism during resistance-exercise training. J Appl Physiol 81: 2095–2104, 1996.
4. Portal S, Zadik Z, Rabinowitz J, Pilz-Burstein R, Adler-Portal D, Meckel Y, Cooper DM, Eliakim A, Nemet D. The effect of HMB supplementation on body composition, fitness, hormonal and inflammatory mediators in elite adolescent volleyball players: A prospective randomized, double-blind, placebo-controlled study. Eur J Appl Physiol 111: 2261–2269, 2011.
5. Wilson JM, Joy JM, Lowery RP, Roberts MD, Lockwood CM, Manninen AH, Fuller JC, De Souza EO, Baier SM, Wilson SM, Rathmacher JA. Effects of oral adenosine-5'-triphosphate supplementation on athletic performance, skeletal muscle hypertrophy and recovery in resistance-trained men. Nutr Metab (Lond) 10: 57, 2013.
6. Wilson JM, Lowery RP, Joy JM, Andersen JC, Wilson SM, Stout JR, Duncan N, Fuller JC, Baier SM, Naimo MA, Rathmacher J. The effects of 12 weeks of beta-hydroxy-beta-methylbutyrate free acid supplementation on muscle mass, strength, and power in resistance-trained individuals: A randomized, double-blind, placebo-controlled study. Eur J Appl Physiol 114: 1217–1227, 2014.