|HIIT on the rowing machine is a powerful fat loss tool even w/out HMB. It's yet also pretty intense, so I'd suggest that you don't do it everyday | learn more|
Against that background it is not totally obvious to do what Krzysztof Durkalec-Michalski and Jan Jeszka did in their latest study: To assess the effect of HMB supplementation on physical capacity, body composition and levels of biochemical markers in endurance athletes, elite rowers to be precise.
The study design was simple, yet effective: 16 elite male rowers, aged 20± 2 years, with a body weight of 87.3 ± 9.8 kg and a height of 187 ± 5 cm consumed 3×1 g HMB/day or an identically looking placebo for 2×12 weeks. "2×12"? Yes, the study wasn't just randomized, placebo controlled, and double-blinded, it was also a crossover study with a 10 days washout period between the first and the second 12 week period. This makes the results more reliable - in spite of the low number of subjects.
|Figure 1: Overview of the design of this double-blind, randomized, controlled crossover trial (Durkalec-Michalsky. 2015)|
|Figure 2: While it looks like there was a sign. testosterone (T) boost in the HMB group, the p-value is 0.569. Accordingly, only the fat mass changes showed sign. inter-group differences (Durkalec-Michalsky. 2015).|
- the ventilatory threshold, the threshold load, and the heart rat, which are the time-point, wattage, and heart rate at which further increases in respiration will no longer lead to increases in VO2 intake, were postponed by +1.2 min, +0.42 W, and +9bpm, respectively,
- with -0.9 kg the subjects in the HMB group lost body fat, while the subjects in the PLA groups gained 0.8 kg (p = 0.03), and lastly
- the refusal time to continue (a proxy of short term recovery) in the progressive test was extended (p = 0.04), maximum load (p = 0.04) and anaerobic peak power (p = 0.02) increased.
What is interesting is that all these benefits occurred in the absence of changes in anaerobic adaptation or blood marker levels. This is cool, but it's also a problem, because as long as we don't know the mechanisms, it's hard to predict (a) who would benefit (most), (b) which supplements would act as synergists and (c) which supplements work via the same pathways so that taking them would make the use of HMB obsolete.References:
- Durkalec-Michalski, Krzysztof, and Jan Jeszka. "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." Journal of the International Society of Sports Nutrition 12.1 (2015): 1-11.
- Wilson, Gabriel J., et al. "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." European Journal of Applied Physiology (2014)