title: Beetroot Juice Improves On-Water 500 M Time-Trial Performance, and Laboratory-Based Paddling Economy in National and International-Level Kayak Athletes.
abstract: We assessed the ingestion of a beetroot juice supplement (BR) on 4-min laboratory-based kayak performance in national level male (n = 6) athletes (Study A), and on 500 m on-water kayak time-trial (TT) performance in international level female (n = 5) athletes (Study B). In Study A, participants completed three laboratory-based sessions on a kayak ergometer, including a 7 × 4 min step test, and two 4 min maximal effort performance trials. Two and a half hours before the warm-up of each 4 min performance trial, athletes received either a 70 ml BR shot containing ~4.8 mmol of nitrate, or a placebo equivalent (BRPLA). The distance covered over the 4 min TT was not different between conditions; however, the average VO2 over the 4 min period was significantly lower in BR (p = .04), resulting in an improved exercise economy (p = .05). In Study B, participants completed two field-based 500 m TTs, separated by 4 days. Two hours before each trial, athletes received either two 70 ml BR shots containing ~9.6 mmol of nitrate, or a placebo equivalent (BRPLA). BR supplementation significantly enhanced TT performance by 1.7% (p = .01). Our results show that in national-level male kayak athletes, commercially available BR shots (70 ml) containing ~4.8 mmol of nitrate improved exercise economy during laboratory-based tasks predominantly reliant on the aerobic energy system. Furthermore, greater volumes of BR (140 ml; ~9.6 mmol nitrate) provided to international-level female kayak athletes resulted in enhancements to TT performance in the field.
authors.affiliation: School of Sports Science, Exercise and Health. University of Western Australia. Crawley, Western Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Peeling
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Cox
authors.forename: Nicola
authors.initials: N
authors.lastname: Bullock
authors.forename: Louise M
authors.initials: LM
authors.lastname: Burke
mesh_terms: D000328:Adult; D056352:Athletes; D054874:Athletic Performance / Q000502:physiology*; D027461:Beta vulgaris; D019587:Dietary Supplements; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D000067030:Fruit and Vegetable Juices; D006801:Humans; D008297:Male; D009566:Nitrates / Q000008:administration & dosage*; D064133:Sports Nutritional Physiological Phenomena; D014867:Water; D055815:Young Adult
chemical_list: D009566:Nitrates; D014867:Water