Effect of beet juice supplementation (BJ) on neuromuscular response: a systematic review

Abstract

Abstract. Beet juice (BJ) is a nutritional source rich in nitrate (NO₃^-) which, after ingestion, is reduced to nitric oxide (NO). NO has effects such as reduction in arterial pressure, anti-inflammatory effects, enhancement of mitochondrial efficiency, and regulation of muscle contractility. Different studies have reported that BJ supplementation has an ergogenic effect in modalities of cardiorespiratory endurance and explosive and intermittent high intensity efforts. Nevertheless, no review has assessed the effect of BJ supplementation on muscle strength production. Thus, the objective of this systematic review is to analyse the effect of BJ supplementation on muscle strength performance. The search using keywords and Boolean connectors was carried out in the databases Dialnet, Directory of Open Access Journals, Medline, Pubmed, Scielo, Scopus, and SPORTDiscus. The search strategy used was the following: (nitrate OR beet *) AND (concept 2) (supplement * OR nutr * OR diet *) AND (concept 3) (strength OR "resistance exercise" OR "resistance training" OR "muscular power "). After the application of the inclusion criteria, a total of 14 articles were selected for review. The review has shown how BJ supplementation can have an ergogenic effect on the production of muscle strength under electrical stimulation, as well as on the production of power over isokinetic contractions only at high angular speeds, the explanatory mechanism being a potentiation of the contractile capacity specifically in type II muscle fibers.