Department of Nutrition, Exercise and Sports, August Krogh Institute, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark.
Team Danmark (Danish Elite Sport Organisation), Brondby Stadion 20, 2605, Brondby, Denmark.
Eur J Appl Physiol. 2019 Jun;119(6):1419-1429. doi: 10.1007/s00421-019-04132-7. Epub 2019 Apr 27.
To evaluate the effect of antioxidant supplementation on intense endurance exercise performance and the physiologic exercise response acutely and in early recovery.
Well-trained cyclists (n = 11, peak VO: 69 ± 7 ml/min/kg) completed two identical standardized 20-min warm-up periods (WU-1 and WU-2) prior to two performance tests (PT) with a duration of ~ 4 min representing a qualifying (PT-1) and final race (PT-2) on the same day separated by 90 min. Subjects were supplemented orally with placebo (PLA) and N-acetyl cysteine (NAC; 20 mg/kg) before exercise in a double-blinded crossover design.
Mean power during PT-1 did not differ (P = 0.39) between PLA (400 ± 44 W) and NAC (401 ± 44 W) as was the case during PT-2 with similar performance (P = 0.74) between PLA (401 ± 43 W) and NAC (400 ± 42 W). Subjective "readiness" was lowered by prior exhaustive exercise from PT-1 to PT-2 (P = 0.012) in both PLA and NAC. Plasma total antioxidant capacity was not affected by supplementation and prior exhaustive exercise (respective main effects: P = 0.83 and P = 0.19) which also was observed for peak VO at ~ 5 L/min (P = 0.84 and P = 0.30). In WU-1 and WU-2, both cycling economy at ~ 20% (P = 0.10 and P = 0.21) and plasma potassium at ~ 5 mmol/L (P = 0.46 and P = 0.26) were unaffected by supplementation and prior exercise.
Athletes executing maximal efforts of a ~ 4-min duration twice daily, as seen in track cycling, appear to gain no benefit from oral NAC supplementation on acute and subsequent performance following short-term recovery. Moreover, well-trained cyclists exhibit rapid recovery from a single bout of intense endurance cycling.
评估抗氧化补充剂对高强度耐力运动表现的影响，以及在急性和早期恢复时的生理运动反应。
11 名训练有素的自行车运动员（峰值 VO：69±7ml/min/kg）在两次相同的 20 分钟热身期（WU-1 和 WU-2）之前完成了两次相同的 4 分钟左右的运动测试（PT），这代表了当天的资格赛（PT-1）和决赛（PT-2），间隔 90 分钟。受试者以双盲交叉设计口服安慰剂（PLA）和 N-乙酰半胱氨酸（NAC；20mg/kg）。
PT-1 期间的平均功率在 PLA（400±44W）和 NAC（401±44W）之间没有差异（P=0.39），PT-2 期间的运动表现也相似（P=0.74），PLA（401±43W）和 NAC（400±42W）之间没有差异。在 PLA 和 NAC 中，先前的耗尽性运动使“准备”在 PT-1 到 PT-2 期间降低（P=0.012）。补充剂和先前的耗尽性运动对血浆总抗氧化能力没有影响（各自的主要影响：P=0.83 和 P=0.19），这也观察到在接近 5L/min 的峰值 VO（P=0.84 和 P=0.30）。在 WU-1 和 WU-2 中，两次运动的经济性都在 20%左右（P=0.10 和 P=0.21），血浆钾也在 5mmol/L 左右（P=0.46 和 P=0.26），补充剂和先前的运动对其没有影响。
在赛道自行车运动中，每天进行两次持续约 4 分钟的最大努力，运动员似乎从口服 NAC 补充剂中无法获得急性和短期恢复后随后的表现的益处。此外，训练有素的自行车运动员从单次高强度耐力自行车运动中迅速恢复。
