Research Section for Behavioral Regulation and Health, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, 1016 Blockley Hall, 423 Guardian Drive, 19104, Philadelphia, USA.
Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Berlin, 10117, Germany.
J Int Soc Sports Nutr. 2020 Mar 12;17(1):16. doi: 10.1186/s12970-020-0336-1.
The leucine metabolite β-hydroxy-β-methylbutyrate (HMB) is widely used as an ergogenic supplement to increase resistance-training induced gains in fat free mass (FFM) and strength in healthy adults. Recent studies have questioned the effectiveness of HMB, particularly when a high protein diet is habitually consumed. To investigate the additive resistance-training induced effects of HMB and protein in untrained individuals, we conducted a randomized double-blind, placebo-controlled study that compared the effects of combined protein and HMB supplementation to protein supplementation alone on FFM and muscle strength after 12-week resistance training.
Sixteen healthy men (22 ± 2 yrs) performed a periodized resistance-training program for twelve weeks (four sessions per week). The program comprised two mesocycles, characterized by a linear periodization and non-linear periodization, respectively, and separated by a 1-week tapering period. All participants received 60 g of whey protein on training days and 30 g of whey protein (WP) on non-training days. Participants were randomly assigned to additionally receive 3 g of calcium HMB (WP + HMB) or a placebo (WP + PLA). Body composition and physical fitness were tested before and after the 12-week training program. Whole-body and arm and leg fat free mass (FFM) were assessed by bioimpedance spectroscopy; upper arm and leg fat free cross sectional areas were also quantified using magnetic resonance imaging (MRI); upper and lower body strength were measured by One-repetition maximum (1-RM) bench press and leg press.
Whole-body and segmental FFM increased in both groups (P < 0.001). However, gains in leg FFM were higher in WP + HMB vs. WP + PLA (arm FFM: + 6.1% vs. + 9.2%, P = 0.2; leg FFM: + 14.2% vs. + 7.0%, P < 0.01). No change in fat mass was observed (P = 0.59). 1-RM increased in both groups (P < 0.001).
Combined protein and HMB supplementation resulted in segmental, but not whole-body increases in FFM compared to protein supplementation alone. These findings could explain some of the controversial effects of HMB reported in previous studies and have practical implications for maximizing training-induced gains in FFM and clinical conditions associated with skeletal muscle deconditioning such as aging, sedentary lifestyles, bed rest and spaceflight.
亮氨酸代谢物β-羟基-β-甲基丁酸（HMB）被广泛用作一种运动补剂，以增加健康成年人的抗阻训练引起的去脂体重（FFM）和力量的增加。最近的研究对 HMB 的有效性提出了质疑，特别是当习惯性地摄入高蛋白饮食时。为了研究 HMB 和蛋白质在未经训练的个体中的抗阻训练诱导作用的相加效应，我们进行了一项随机双盲、安慰剂对照研究，比较了 12 周抗阻训练后，同时补充蛋白质和 HMB 与单独补充蛋白质对 FFM 和肌肉力量的影响。
16 名健康男性（22±2 岁）进行了为期 12 周的周期性抗阻训练计划（每周 4 次）。该方案包括两个中周期，分别以线性和非线性分期为特征，并通过 1 周的减量期隔开。所有参与者在训练日摄入 60g 乳清蛋白，在非训练日摄入 30g 乳清蛋白（WP）。参与者被随机分配额外接受 3g 钙 HMB（WP+HMB）或安慰剂（WP+PLA）。在 12 周训练计划前后测试身体成分和身体适应能力。全身和手臂及腿部去脂体重（FFM）通过生物阻抗谱法评估；通过磁共振成像（MRI）也定量评估上臂和腿部去脂横截面积；通过 1 次重复最大（1-RM）卧推和腿推测量上下体力量。
两组全身和节段性 FFM 均增加（P<0.001）。然而，与 WP+PLA 相比，WP+HMB 组的腿部 FFM 增加更多（手臂 FFM：+6.1%对+9.2%，P=0.2；腿部 FFM：+14.2%对+7.0%，P<0.01）。脂肪量无变化（P=0.59）。1-RM 在两组均增加（P<0.001）。
与单独补充蛋白质相比，联合补充蛋白质和 HMB 导致节段性但非全身 FFM 增加。这些发现可以解释以前研究中报道的 HMB 的一些有争议的作用，并对最大限度地提高抗阻训练引起的 FFM 增加和与骨骼肌去适应相关的临床状况（如衰老、久坐生活方式、卧床休息和太空飞行）具有实际意义。
