We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
A COMPARISON OF TWO NITRATE DOSING STRATEGIES ON HIGH INTENSITY CYCLING PERFORMANCE IN HIGHLY-TRAINED CYCLISTS.
- Authors
McQuillan, Joseph A.; Dulson, Deborah K.; Laursen, Paul B.; Kilding, Andrew E.
- Abstract
Background (optional): In recent times dietary nitrate (NO3-) supplementation has been championed as an ergogenic aid to reduce blood pressure, increase time to exhaustion, and enhance time-trial performance in moderate- to well-trained athletic populations. Initial reports suggested that athletes of moderate fitness levels improved time-trial performance in events of 6 to 30 mins by 1.3 to 2.8%. Subsequently, further research employing highly-trained populations over similar time-frames have shown more neutral outcomes. Purpose: To compare the effects of two different dosing durations of dietary nitrate (NO3-) supplementation on 1- and 4-km cycling time-trial cycling performance in highly-trained cyclists. Methods: In a double-blind crossover-design, on a daily basis nine highlytrained cyclists ingested 140ml of NO3--rich beetroot juice containing ~8.0mmol [NO3-], or placebo, for seven days. Participants completed a range of laboratory-based trials to quantify physiological and perceptual responses and cycling performance: time-trial on days 3 and 6 (4-km) and on days 4 and 7 (1-km) of the supplementation period. Results: Relative to placebo, effects following 3- and 4-days of NO3- supplementation were unclear for 4-km (-0.8;95%CL, ±2.8%, P=0.64) and likely harmful for 1-km (-1.9;±2.6%CL, P=0.17) time-trial mean power. Effects following 6- and 7-days of NO3- supplementation resulted in unclear effects for 4- (0.1;±2.2%CL, P=0.93) and 1-km (-0.9;±2.6%CL, P=0.51) time-trial mean power. There were possibly beneficial enhancements in economy, relative to placebo, at 50 (0.14;±0.24%CL, P=0.42) and 60% (0.13;±0.29%CL, P=0.87) peak power output after 3-days NO3- supplementation. Effects were trivial or unclear for remaining measures. Conclusions: Dietary NO3- supplementation appears to be detrimental to 1-km time-trial performance in highly-trained cyclists after 4-days. Whilst, extending NO3- dosing to ≥6-days reduced the magnitude of harm in both distances, overall performance in short duration cycling time-trials did not improve relative to placebo.
- Subjects
PHYSIOLOGICAL effects of nitrates; CYCLING; CYCLIST physiology
- Publication
New Zealand Journal of Sports Medicine, 2017, Vol 44, Issue 1, p36
- ISSN
0110-6384
- Publication type
Abstract