An additional confounding variable in this study was that skeletal muscle hypertrophy (FFM) was estimated from bioelectrical impedance, which has been demonstrated to Lumacaftor have high variability [49]. Finally, the outcome strength measures were single joint movements (e.g., biceps curl and leg extension). If HMB increases overall lean mass, it may have been more appropriate to select multi-joint, structural exercises

such as the squat and/or bench press. However, even with these limitations nine weeks of HMB-Ca supplementation resulted in small, but statistically significant decreases in FM, and increases in FFM and strength. To date, few studies have examined monitored resistance training in trained athletes [7, 18, 20, 42]. Of these, only one exceeded six weeks in duration. The first was conducted by Kreider et al. [18] who examined the effects of four weeks of HMB supplementation during a supervised offseason strength MG-132 research buy and conditioning program in college football players and observed no changes in lean mass or strength. However,

Panton et al. [20], examined the effects of four weeks of HMB supplementation during resistance training in 36 women and 39 men (20–40 yrs) with varying levels of training experience. Their training protocol consisted of very high intensity loads (>80 % 1-RM) which were consistently adjusted as subject tolerance for a given weight increased. Due O-methylated flavonoid to the high intensity nature of the protocol, the HMB-Ca group showed greater decreases in body fat compared with placebo supplementation (−1.1 % vs. -0.5%, respectively); increases in bench press strength (7.5 kg vs. 5.2 kg, respectively); and LBM (1.4 kg vs.0.9 kg, respectively). These changes were independent of training experience. Moreover, Nissen et al. [7] conducted a seven week high intensity (>80% 1-RM) training study in individuals who could bench press ≥ 135 kg and squat greater than 1.5 times their bodyweight and found that

subjects supplemented with HMB-Ca gained an average of 4.5 kg more on their bench press and 3.2 kg more on their squat when compared to the placebo supplemented subjects. Collectively the findings presented in Table 2 lead us to the following conclusions: 1) in untrained individuals, HMB can enhance muscle hypertrophy and dynamic strength in as little as three weeks; however, 2) for trained individuals it is important to realize that adaptations occur at a slower rate than in untrained individuals [46]. For this reason, HMB will likely be most beneficial over longer training durations (> 6 weeks) in trained individuals. HMB supplementation has been demonstrated to result in modest increases in strength during unsupervised, resistance training programs greater than six weeks in duration.