Muggeridge David J, Sculthorpe Nicholas, James Philip E, Easton Chris
Institute for Clinical Exercise and Health Science, University of the West of Scotland, UK.
Wales Heart Research Institute, Cardiff University Medical School, UK.
J Sci Med Sport. 2017 Jan;20(1):92-97. doi: 10.1016/j.jsams.2016.04.014. Epub 2016 May 21.
Dietary nitrate can improve repeated high-intensity and supramaximal exercise performance, although the effect on adaptations to training has received limited attention. The purpose of this study was to investigate the effects of dietary nitrate on the response to 3-weeks of sprint interval training (SIT).
Randomized control trial.
Twenty-seven untrained males (Age: 28±7 y, V⋅O: 42±7mlkgmin) completed an incremental exercise test at the beginning and end of the study. Participants were matched for V⋅O and randomly assigned to a control group (CON; n=8), SIT+placebo group (PLA; n=10), or SIT+nitrate group (NIT; n=9). The SIT comprised 4-6 repeated 15 s all out sprints on a cycle ergometer, interspersed with 4min active recovery, 3-times per week. Approximately 2.5h prior to exercise, participants consumed gels containing ∼0.1mmol (PLA) or ∼8mmol nitrate (NIT).
Following SIT, V⋅O (PLA: 5%, p=0.057, d=0.34; NIT: 6.3%, p=0.041, d=0.34) and ventilatory threshold (VT) increased to a similar extent in both SIT groups. Maximum work rate tended to increase to a greater extent in NIT (8.7%, d=0.55) compared to PLA (4.7%, d=0.31, p=0.073). Fatigue index, calculated by the change in mean power from the first to the last sprint, tended to be reduced following SIT in NIT compared to PLA (PLA: 7.3±7.4%, NIT: 0.5±7.1%, p=0.058).
While dietary nitrate supplementation does not augment improvements to V⋅O and VT following SIT, it may improve WR and indices of repeated high-intensity exercise.
膳食硝酸盐可改善重复高强度和超最大强度运动表现，尽管其对训练适应性的影响受到的关注有限。本研究的目的是调查膳食硝酸盐对3周冲刺间歇训练（SIT）反应的影响。
随机对照试验。
27名未经训练的男性（年龄：28±7岁，摄氧量：42±7ml·kg⁻¹·min⁻¹）在研究开始和结束时完成递增运动试验。参与者根据摄氧量进行匹配，并随机分配到对照组（CON；n = 8）、SIT+安慰剂组（PLA；n = 10）或SIT+硝酸盐组（NIT；n = 9）。SIT包括在自行车测力计上进行4 - 6次重复的15秒全力冲刺，中间穿插4分钟的主动恢复，每周3次。在运动前约2.5小时，参与者食用含有约0.1mmol（PLA）或约8mmol硝酸盐（NIT）的凝胶。
SIT后，两个SIT组的摄氧量（PLA：5%，p = 0.057，d = 0.34；NIT：6.3%，p = 0.041，d = 0.34）和通气阈值（VT）增加程度相似。与PLA（4.7%，d = 0.31，p = 0.073）相比，NIT组的最大工作率增加幅度更大（8.7%，d = 0.55）。与PLA组相比，NIT组SIT后疲劳指数（通过第一次到最后一次冲刺的平均功率变化计算）有降低趋势（PLA：7.3±7.4%，NIT：0.5±7.1%，p = 0.058）。
虽然补充膳食硝酸盐不会增强SIT后摄氧量和通气阈值的改善，但可能改善最大工作率和重复高强度运动指标。
