Institute of Sport Medicine, Hannover Medical School , Hannover , Germany.
Institute of Sports Science, Leibniz University Hannover , Hannover , Germany.
J Appl Physiol (1985). 2018 Dec 1;125(6):1997-2007. doi: 10.1152/japplphysiol.00176.2018. Epub 2018 Oct 25.
The aim of this study was to investigate the later effects of daily supplementation over 3 wk of training on the relationship between O uptake and power at different intensities with an incremental test (IT), a double-wingate test (WT), and an endurance capacity test at 80% W (ECT) before and after the supplementation period. Seventeen male recreational athletes participated in this double-blind placebo (PL)-controlled study. Subjects participated in a 3-wk intermittent high-intensity, high-volume training period with 45 intervals of W - 10 W and an active recovery period of 10 W in between with dietary (NaNO) or placebo supplementation (NaCl) (both 8.5 mg·kg·day) on a cycle ergometer. During a training session, plasma [ ] ( P < 0.001) and plasma [ ] ( P < 0.01) were higher in nitrate (N), whereas in pre- and posttests mean plasma [ ] and [ ] were not different between groups. In the WT [48 h after cessation of supplementation (C)], the ratio between V̇o and power decreased in N ( P < 0.01) with no changes in PL. Endurance capacity (4-5 days after C) similarly increased in both groups ( P < 0.01). However, the total oxygen consumption decreased by 5% ( P < 0.01) in N, with no change in PL. The slope of V̇o·W in IT (5-7 days after C) decreased in N ( P < 0.01), whereas no changes were found in PL. During low- and moderate-intensity workloads, no changes and differences in V̇o could be detected. We conclude that nitrate supplementation causes a sustaining reduction of the oxygen cost per watt during exercise with a large recruitment of type II muscle fibers without affecting endurance capacity. NEW & NOTEWORTHY Because most studies focused on the acute effects of supplementation on exercise performance during a supplementation period, the sustainability of the effects of the supplementation remain unknown. We followed the development of V̇o/W at different intensities during the first week after cessation of daily supplementation over 3 wk. The results indicate that supplementation has a long-term effect for at least 7 days after cessation during heavy all-out workloads without affecting endurance capacity.
这项研究的目的是在补充期前后，通过递增测试（IT）、双翼测试（WT）和 80% W 的耐力能力测试（ECT），研究 3 周训练期间每天补充对不同强度下 O 摄取量和功率之间关系的后期影响。17 名男性休闲运动员参加了这项双盲安慰剂（PL）对照研究。受试者参加了为期 3 周的间歇性高强度、高容量训练，期间在自行车测力计上进行 45 次 W-10 W 间隔，中间有 10 W 的主动恢复期，并进行饮食补充（NaNO）或安慰剂补充（NaCl）（均为 8.5mg·kg·day）。在训练过程中，硝酸盐（N）组的血浆[ ]（P<0.001）和血浆[ ]（P<0.01）升高，而在预测试和后测试中，两组之间的平均血浆[ ]和[ ]没有差异。在 WT（补充停止后 48 小时（C））中，Vo 和功率之间的比值在 N 中降低（P<0.01），而在 PL 中没有变化。耐力能力（C 后 4-5 天）在两组中均增加（P<0.01）。然而，N 组的总耗氧量减少了 5%（P<0.01），PL 组没有变化。IT（C 后 5-7 天）中 Vo·W 的斜率在 N 中降低（P<0.01），而 PL 中没有变化。在低强度和中等强度的工作量下，Vo 没有变化和差异。我们得出的结论是，硝酸盐补充剂在补充期内可减少运动时每瓦特的耗氧量，同时大量招募 II 型肌纤维，而不会影响耐力能力。新的和值得注意的是，因为大多数研究都集中在补充期间补充对运动表现的急性影响，所以补充的影响的可持续性仍然未知。我们在 3 周补充期后，在第一周内跟踪不同强度下 Vo/W 的发展情况。结果表明，补充剂在停止补充后至少 7 天内对高强度全力工作仍有长期影响，而不会影响耐力能力。
