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.

Fiber Type-Specific Effects of Dietary Nitrate

“…The lack of an ergogenic effect with NO 3 j supplementation in these studies might be attributable to an insufficient supplementation dose and/or duration to elicit the skeletal muscle and mitochondrial remodeling that underpins some of the positive physiological responses reported elsewhere (16,22) and to the lower percentage of Type II fibers in the locomotor muscles of elite endurance athletes (33). An interesting exception in this regard is that NO 3 j ingestion resulted in significantly improved exercise economy in a laboratory exercise test and significantly improved on-water time trial performance in elite kayakers (29). This is intriguing in relation to the hypothesis advanced in the current article because the upper body musculature typically has a higher fraction of Type II muscle fibers (17).…”

Performance Enhancement: What Are the Physiological Limits?

“…Improvements in economy and performance were also observed in elite kayakers (78). However, using a randomized, placebo-controlled crossover study design, Christensen et al were not able to reproduce these previous findings in trained cyclists with a V O 2max (18).…”

Nitrate pharmacokinetics: Taking note of the difference

“…There is no observable trend to indicate higher baseline plasma levels influence the peak yield, but this remains to be tested directly. Figure 3 shows the scatter between measured plasma [NO The influence of NO 3 -supplementation on a wide range of exercise activities has been investigated, ranging from 500 m kayaking [24] to 50 miles cycling [25], with predictably mixed results. While the majority of studies to date have assessed the influence of NO 3 -supplementation on continuous exercise, a few have considered possible effects on intermittent high-intensity exercise tests which are reflective of the pattern of exertion during team sports.…”

“…It is important to note, however, that it is possible that elite athletes will respond better to NO 3 -supplementation with larger doses or more protracted supplementation regimens. Irrespective of training status, it has been suggested that there may be 'responders' and 'non-responders' to NO 3 -supplementation [24], and this also may explain …”