Cardiorespiratory/Metabolic Laboratory, The University of Memphis, Memphis, Tennessee, USA.
J Strength Cond Res. 2012 Jun;26(6):1680-7. doi: 10.1519/JSC.0b013e318236d081.
Nitric oxide dietary supplements are popular within the sport community. Our recent work involving the oral intake of 2-nitrooxy ethyl 2-amino 3-methylbutanoate demonstrated an approximately 6.7% increase in circulating nitrate/nitrite. However, no measures of exercise performance were obtained. The present study used a topical form of this molecule to determine the impact on exercise performance and blood nitrate/nitrite. Fourteen resistance trained men (24 ± 1 years old) reported to the laboratory on 2 occasions to undergo exercise testing, which consisted of arm curl isometric force and muscular endurance (3 sets to fatigue using 80, 65, and 50% of 1 repetition maximum [1RM]: total of 9 sets). The gel (2-nitrooxy ethyl 2-amino 3-methylbutanoate; mixed in tea tree oil) or placebo (tea tree oil) was applied topically by the subjects for 7 days before each test day, with 7-10 days separating the randomly ordered conditions. Blood samples, arm circumference, and perceived "muscle pump" were taken before and immediately after exercise on both test days. The heart rate and perceived exertion were measured after each set. No statistically significant differences were noted between conditions for performance variables (p > 0.05). However, when using a load of 50% of 1RM, 6.2% more repetitions were performed when using the gel as compared with when using the placebo; 19.9% more repetitions were performed by 8 subjects noted to be "responders" to gel treatment. Blood lactate and muscle pump significantly increased with exercise (p < 0.0001) but were not different between conditions (p > 0.05). Minimal change was noted in nitrate/nitrite, and the heart rate and perceived exertion were nearly identical between conditions (p > 0.05). These findings indicate that 2-nitrooxy ethyl 2-amino 3-methylbutanoate gel has a modest (6.2%), nonstatistically significant effect on exercise performance, in particular when using a load of 50% 1RM-with greater benefit noted in selected individuals. Studies inclusive of a larger sample size are needed to extend these initial findings.
一氧化氮膳食补充剂在运动界很受欢迎。我们最近的研究涉及口服 2-硝基氧基乙基 2-氨基 3-甲基丁酸酯，结果表明循环硝酸盐/亚硝酸盐增加了约 6.7%。然而，没有获得运动表现的测量结果。本研究使用这种分子的局部形式来确定其对运动表现和血液硝酸盐/亚硝酸盐的影响。14 名受过抗阻训练的男性（24±1 岁）在 2 次就诊时报告至实验室进行运动测试，运动测试包括手臂卷曲等长力量和肌肉耐力（使用 80%、65%和 50%的 1 次重复最大值[1RM]进行 3 组至疲劳：共 9 组）。凝胶（2-硝基氧基乙基 2-氨基 3-甲基丁酸酯；混合茶树油）或安慰剂（茶树油）在每次测试前 7 天由受试者局部应用，随机顺序条件之间间隔 7-10 天。在两次测试日的运动前后，分别在运动前后采集血液样本、手臂周长和感知的“肌肉泵”。每次运动后测量心率和感知的用力程度。在性能变量方面，条件之间没有统计学上的显著差异（p＞0.05）。然而，当使用 50%的 1RM 负荷时，与使用安慰剂相比，使用凝胶时多完成了 6.2%的重复次数；19.9%的重复次数是由 8 名被认为对凝胶治疗有“反应”的受试者完成的。血液乳酸和肌肉泵随着运动显著增加（p＜0.0001），但条件之间没有差异（p＞0.05）。硝酸盐/亚硝酸盐的变化很小，条件之间的心率和感知用力程度几乎相同（p＞0.05）。这些发现表明，2-硝基氧基乙基 2-氨基 3-甲基丁酸酯凝胶对运动表现有适度（6.2%）、非统计学显著的影响，特别是在使用 50%1RM 负荷时——在某些个体中观察到更大的益处。需要进行包括更大样本量的研究来扩展这些初步发现。
