Background Energy drinks are often consumed by the general population, as well as by active individuals seeking to enhance exercise performance and augment training adaptations. However, limited information is available regarding the efficacy of these products. Thus, the purpose of this study was to determine the effects of a commercially available caffeine- and protein-containing energy drink on metabolism and muscular performance. Methods Sixteen resistance-trained males ( n = 8; mean ± SD; age: 22.4 ± 4.9 years; body mass: 78.8 ± 14.0 kg; body fat: 15.3 ± 6.4%) and females ( n = 8; age: 24.5 ± 4.8 years; body mass: 67.5 ± 11.9 kg; body fat: 26.6 ± 7.1%) participated in this randomized, double-blind, placebo-controlled, crossover study. Following a familiarization visit, participants completed two identical visits to the laboratory separated by 5–10 days, each of which consisted of indirect calorimetry energy expenditure (EE) assessments before and after consumption of the beverage (Bang® Keto Coffee; 130 kcal, 300 mg caffeine, 20 g protein) or placebo (30 kcal, 11 mg caffeine, 1 g protein) as well as after exercise testing. In addition, participants’ subjective feelings of energy, fatigue, and focus as well as muscular performance (leg press one-repetition maximum and repetitions to fatigue, maximal isometric and isokinetic squat testing) were assessed. Multiple repeated measures ANOVAs with Tukey post-hoc tests were used to analyze data. Estimates of effect size were quantified via partial eta squared (η P 2 ) and Hedge’s g. Results A significant interaction effect was identified for EE ( p < 0.001, η P 2 = 0.52) but not respiratory exchange ratio ( p = 0.17, η P 2 = 0.11). Following consumption of the beverage, EE was 0.77 kcal·min − 1 greater than placebo at the post-beverage time point ( p < 0.001) and 0.37 kcal·min − 1 greater than placebo at the post-exercise time point ( p = 0.011). However, no between-condition differences were detected for any subjective or muscular performance outcomes. Conclusions The results of this study suggest that consumption of the energy drink had minimal effects on lower-body muscular performance and subjective factors in the context of a laboratory setting. However, the beverage was found to significantly increase energy expenditure compared to placebo immediately following ingestion as well as during the recovery period after an exercise bout, suggesting that active individuals may improve acute metabolic outcomes via consumption of a caffeine- and protein-containing energy drink. Trial registration This trial was prospectively registered at ClinicalTrials.gov (Identifier: NCT04180787 ; Registered 29 November 2019).

中文翻译：

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Bang® Keto 咖啡能量饮料对接受阻力训练的成年人代谢和运动表现的影响：一项随机、双盲、安慰剂对照、交叉研究


背景技术 能量饮料通常由普通人群以及寻求提高运动表现和增强训练适应性的活跃个体饮用。然而，有关这些产品功效的信息有限。因此，本研究的目的是确定市售的含咖啡因和蛋白质的能量饮料对新陈代谢和肌肉性能的影响。方法 16 名接受阻力训练的男性（n = 8；平均值±SD；年龄：22.4 ± 4.9 岁；体重：78.8 ± 14.0 kg；体脂：15.3 ± 6.4%）和女性（n = 8；年龄：24.5 ± 4.8）年；体重：67.5 ± 11.9 kg；体脂：26.6 ± 7.1%）参加了这项随机、双盲、安慰剂对照的交叉研究。在熟悉访问后，参与者完成了两次相隔 5-10 天的相同实验室访问，每次访问都包括饮用饮料（Bang® Keto 咖啡；130 kcal，300 kcal）之前和之后的间接热量消耗 (EE) 评估。毫克咖啡因，20克蛋白质）或安慰剂（30大卡，11毫克咖啡因，1克蛋白质）以及运动测试后。此外，还评估了参与者对能量、疲劳和注意力的主观感受以及肌肉表现（腿举一次重复最大次数和疲劳重复次数、最大等长和等速深蹲测试）。使用多个重复测量方差分析和 Tukey 事后检验来分析数据。效应大小的估计通过部分 eta 平方 (η P 2 ) 和 Hedge 的 g 进行量化。结果 EE 存在显着的交互作用（p < 0.001，η P 2 = 0.52），但呼吸交换比则没有显着的交互作用（p = 0.17，η P 2 = 0.11）。饮用该饮料后，EE 为 0。在饮料后时间点比安慰剂多 77 kcal·min − 1 (p < 0.001)，在运动后时间点比安慰剂多 0.37 kcal·min − 1 (p = 0.011)。然而，没有检测到任何主观或肌肉表现结果的条件差异。结论 这项研究的结果表明，在实验室环境下，饮用能量饮料对下半身肌肉表现和主观因素的影响极小。然而，与安慰剂相比，该饮料被发现在摄入后以及运动后的恢复期间显着增加能量消耗，这表明活跃的个体可以通过饮用含有咖啡因和蛋白质的能量饮料来改善急性代谢结果。试验注册 该试验在 ClinicalTrials.gov 上前瞻性注册（标识符：NCT04180787；注册于 2019 年 11 月 29 日）。