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Influence of dietary nitrate supplementation on high-intensity intermittent running performance at different doses of normobaric hypoxia in endurance-trained males
journal contribution
posted on 2020-12-04, 15:13 authored by George RobinsonGeorge Robinson, Sophie Killer, Zdravko Stoyanov, Harri Stephens, Luke Read, Lewis JamesLewis James, Stephen BaileyStephen BaileyThis study investigated whether supplementation with nitrate-rich beetroot juice (BR) can improve high-intensity intermittent running performance in trained males in normoxia and different doses of normobaric hypoxia. Eight endurance-trained males (V˙O2peak, 62 ± 6 ml·kg−1·min−1) completed repeated 90 s intervals at 110% of peak treadmill velocity, from an initial step incremental test, interspersed by 60 s of passive recovery until exhaustion (Tlim). Participants completed the first three experimental trials during days 3, 5, and 7 of BR or nitrate-depleted beetroot juice (PLA) supplementation and completed the remaining experimental visits on the alternative supplement following at least 7 days of washout. The fraction of inspired oxygen during visits 1–3 was either 0.209, 0.182, or 0.157, equivalent to an altitude of 0, 1,200, and 2,400 m, respectively, and this order was replicated on visits 4–6. Arterial oxygen saturation declined dose dependently as fraction of inspired oxygen was lowered (p < .05). Plasma nitrite concentration was higher pre- and postexercise after BR compared with PLA supplementation (p < .05). There was no difference in Tlim between PLA and BR at 0 m (445 [324, 508] and 410 [368, 548] s); 1,200 m (341 [270, 390] and 332 [314, 356] s); or 2,400 m (233 [177, 373] and 251 [221, 323] s) (median and [interquartile range]; p > .05). The findings from this study suggest that short-term BR supplementation does not improve high-intensity intermittent running performance in endurance-trained males in normoxia or at doses of normobaric hypoxia that correspond to altitudes at which athletes typically train while on altitude training camps.
Funding
UK Athletics and English Institute of Sport
History
School
- Sport, Exercise and Health Sciences
Published in
International Journal of Sport Nutrition and Exercise MetabolismVolume
31Issue
1Pages
1-8Publisher
Human KineticsVersion
- AM (Accepted Manuscript)
Rights holder
© Human Kinetics, Inc.Publisher statement
Accepted author manuscript version reprinted, by permission, from International Journal of Sport Nutrition and Exercise Metabolism, 2020, https://doi.org/10.1123/ijsnem.2020-0198. © Human Kinetics, Inc.Acceptance date
2020-09-29Publication date
2021-01-31Copyright date
2021ISSN
1526-484XeISSN
1543-2742Publisher version
Language
- en
Depositor
Dr Stephen Bailey. Deposit date: 29 September 2020Usage metrics
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