Human Performance Research Laboratory, Department of Kinesiology and Health Promotion, California State Polytechnic University, Pomona, Pomona, California.
Research and Development, Shaklee Corporation, Pleasanton, California.
J Strength Cond Res. 2019 Jan;33(1):217-224. doi: 10.1519/JSC.0000000000001958.
Jo, E, Fischer, M, Auslander, AT, Beigarten, A, Daggy, B, Hansen, K, Kessler, L, Osmond, A, Wang, H, and Wes, R. The effects of multiday vs. single pre-exercise nitrate supplement dosing on simulated cycling time trial performance and skeletal muscle oxygenation. J Strength Cond Res 33(1): 217-224, 2019-A transient augmentation in the metabolic efficiency of skeletal muscle is the purported basis for dietary nitrate supplementation amongst competitive and recreational athletes alike. Previous studies support the ergogenic effects of nitrate supplementation, as findings indicated improved microvascular blood flow, exercise economy, and performance with relatively short-term supplementation. As with most ergogenic aids, the optimum duration of supplementation before performance or competition, i.e., loading phase, is a critical determinant for efficacy. Therefore, the purpose of this study was to investigate the effects of long-term vs. single dosing nitrate supplementation on skeletal muscle oxygenation and cycling performance. In a randomized, placebo controlled, double blind, parallel design study, healthy, recreationally active men (n = 15) and women (n = 14) subjects (age = 18-29 years) completed an 8 km (5 mi) simulated cycling time trial before and after a 14-day supplementation period with either a nitrate supplement (Multi-Day Dosing Group) (n = 14) or placebo (Single Pre-Exercise Dosing Group; SD) (n = 15). Both groups consumed a single dose of the nitrate supplement 2 hours before the post-treatment time trial. In addition, skeletal muscle oxygenation was measured via near-infrared spectroscopy during each time trial. Multiday nitrate supplementation significantly decreased time to completion (p = 0.01) and increased average power (p = 0.04) and speed (p = 0.02) from pre-to post-treatment, while a single dosing produced no significant changes to these measures. There were no significant differences over time and across treatments for any other measures including muscle oxygenation variables. Overall, long-term nitrate supplementation appears to have an advantage over a single pre-exercise dosing on cycling performance and metabolic efficiency as indicated by an increase in power output with no change in oxygenation.
乔、E、菲舍尔、M、奥斯拉德、AT、贝加滕、A、达吉、B、汉森、K、凯斯勒、L、奥斯蒙德、A、王、H 和韦斯、R. 多日与单次运动前硝酸盐补充对模拟自行车计时赛表现和骨骼肌氧合的影响。J 力量与调节研究 33(1):217-224,2019-骨骼肌代谢效率的短暂增强是运动营养学家普遍认为饮食硝酸盐补充对竞技和娱乐运动员都有益的基础。先前的研究支持硝酸盐补充的运动表现作用，因为发现表明，在相对短期的补充后，微血管血流、运动经济性和表现得到改善。与大多数运动表现辅助剂一样，在性能或比赛前补充的最佳持续时间，即加载阶段，是功效的关键决定因素。因此，本研究的目的是调查长期与单次剂量硝酸盐补充对骨骼肌氧合和自行车表现的影响。在一项随机、安慰剂对照、双盲、平行设计的研究中，健康的、有规律运动的男性（n = 15）和女性（n = 14）受试者（年龄 = 18-29 岁）在 14 天的补充期后进行了 8 公里（5 英里）模拟自行车计时赛（n = 14）或安慰剂（单预运动剂量组；SD）（n = 15）。两组都在治疗后时间试验前 2 小时内服用单剂量硝酸盐补充剂。此外，在每次时间试验期间，通过近红外光谱测量骨骼肌氧合。多日硝酸盐补充显著降低完成时间（p = 0.01），并增加平均功率（p = 0.04）和速度（p = 0.02）从治疗前到治疗后，而单次剂量没有对这些测量产生显著变化。在时间和治疗方面，没有其他任何措施包括肌肉氧合变量的显著差异。总的来说，长期硝酸盐补充似乎在自行车表现和代谢效率方面优于单次运动前给药，因为功率输出增加而氧合不变。
