The effects of beetroot juice supplementation on exercise economy, rating of perceived exertion and running mechanics in elite distance runners: A double-blinded, randomized study

Abstract

PurposeNitrate-rich beetroot juice supplementation has been extensively used to increase exercise economy in different populations. However, its use in elite distance runners, and its potential effects on biomechanical aspects of running have not been properly investigated. This study aims to analyze the potential effects of 15 days of beetroot juice supplementation on physiological, psychological and biomechanical variables in elite runners.MethodsTwelve elite middle and long-distance runners (age = 26.3 ± 5.1yrs, VO2Max = 71.8±5.2 ml*kg-1*min-1) completed an incremental running test to exhaustion on a treadmill before and after a 15-days supplementation period, in which half of the group (EG) consumed a daily nitrate-rich beetroot juice and the other group (PG) consumed a placebo drink. Time to exhaustion (TEx), running economy, vastus lateralis oxygen saturation (SmO2), leg stiffness and rate of perceived exertion (RPE) were measured at 15, 17.1 and 20 km/h during the incremental test.ResultsLikely to very likely improvements in EG were observed for the RPE (Standardized mean difference (SMD) = -2.17, 90%CI = -3.23, -1.1), SmO2 (SMD = 0.72, 90%CI = 0.03, 1.41) and TEx (SMD = 1.18, 90%CI = -0.14, 2.5) in comparison with PG. No other physiological or biomechanical variable showed substantial improvements after the supplementation period.ConclusionsFifteen days of nitrate-rich beetroot juice supplementation produced substantial improvements in the time to exhaustion in elite runners; however, it didn’t produce meaningful improvements in running economy, VO2Max or mechanical parameters.

Influence of Nitrate Supplementation on Endurance Cyclic Sports Performance: A Systematic Review

“…The methodological quality of the articles, evaluated using McMaster's Critical Review Form [21], ranged between 13 and 15 points, representing a minimum methodological quality of 86.6% and a maximum of 100%. Of the 27 studies, 3 achieved 13 items, representing 11.11% of the total number of studies, 3 achieved 14 items, representing the same percentage of 11.11%, and the rest of the studies (21) achieved 15 items, representing 77.78% of the total number of studies.…”

Effects of Dietary Nitrate Supplementation on Weightlifting Exercise Performance in Healthy Adults: A Systematic Review

“…Dietary supplements, such as creatine, caffeine and sodium bicarbonate, have a strong historical evidence basis to support ergogenic effects in certain exercise settings [ 34 ]. More recently, inorganic nitrate (NO 3 − ) ingestion, often administered as concentrated NO 3 − -rich beetroot juice (BR), has been reported to confer ergogenic effects in various exercise modalities [ 35 ], including running [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ], rowing [ 48 , 49 ], kayaking [ 50 ], knee extensions [ 37 , 51 ] and cycling [ 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ]. Although an ergogenic effect of NO 3 − supplementation appears less likely in endurance-trained individuals, i.e., [ 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 ], recent systematic reviews support its efficacy as an ergogenic aid during continuous endurance-type exercise [ 75 , 76 , 77 ] and high-intensity intermittent-type exercise [ 7...…”

The benefits and risks of beetroot juice consumption: a systematic review

“…Also, time to exhaustion has been shown to significantly improve after 15 days of BRJ supplementation. However, VO 2max wasn't improved after the trial (Balsalobre-Fern andez et al 2018). Another benefit from consuming BRJ for a short period in well-trained rowers was that the maximal rowing-ergometer repetitions improved (Bond, Morton, and Braakhuis 2012).…”

“…Indeed, Hoon et al (2015) found that four-day BRJ supplementation in healthy individuals decreased muscular fatigue in conditions of reduced blood flow during exhaustive exercise (Hoon et al 2015), and Husmann et al (2019) found reduced perceived effort and muscle pain after five-day BRJ ingestion (Husmann et al 2019). Additionally, several studies have found that BRJ improves exercise tolerance or rate of perceived exhaustion in normoxia (Aucouturier et al 2015;Bailey et al 2015;Balsalobre-Fern andez et al 2018;Breese et al 2013;Wylie, Kelly, Fulford, et al 2013) as well as hypoxia (Kelly et al 2014;Vanhatalo et al 2011). Other studies, however, have failed to show such an effect on oxidative stress (Carriker et al 2018), rate of fatigue or perceived exertion (de Castro, de Assis Manoel, et al 2019;Lee et al 2019).…”