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

Alejandro F. San Juan,Juan José Montoya,Stephen J. Bailey,Raul Dominguez,Rachel Tan,Ángel Lago-Rodríguez

doi:10.3390/nu12082227

Abstract

Dietary nitrate (NO3−) supplementation has been evidenced to induce an ergogenic effect in endurance and sprint-type exercise, which may be underpinned by enhanced muscle contractility and perfusion, particularly in type II muscle fibers. However, limited data are available to evaluate the ergogenic potential of NO3− supplementation during other exercise modalities that mandate type II fiber recruitment, such as weightlifting exercise (i.e., resistance exercise). In this systematic review, we examine the existing evidence basis for NO3− supplementation to improve muscular power, velocity of contraction, and muscular endurance during weightlifting exercise in healthy adults. We also discuss the potential mechanistic bases for any positive effects of NO3− supplementation on resistance exercise performance. Dialnet, Directory of Open Access Journals, Medline, Pubmed, Scielo, Scopus and SPORT Discus databases were searched for articles using the keywords: nitrate or beetroot and supplement or nut*r or diet and strength or “resistance exercise” or “resistance training” or “muscular power”. Four articles fulfilling the inclusion criteria were identified. Two of the four studies indicated that NO3− supplementation could increase aspects of upper body weightlifting exercise (i.e., bench press) performance (increases in mean power/velocity of contraction/number of repetitions to failure), whereas another study observed an increase in the number of repetitions to failure during lower limb weightlifting exercise (i.e., back squat). Although these preliminary observations are encouraging, further research is required for the ergogenic potential of NO3− supplementation on weightlifting exercise performance to be determined.

Highlights

Weightlifting exercise is well established as an exercise modality of resistance exercise to improve skeletal muscle mass [1,2], strength [3,4,5], endurance [6,7] and power [8,9]
In contrast to the rodent studies, there was an increase in evoked contractile force after NO3 − supplementation without an effect on muscle Ca2+ -handling proteins in human skeletal muscle [96]. These findings suggest that dietary NO3 − supplementation has the potential to increase contractile force production, skeletal muscle power and velocity of contraction, in type II muscle fibers, which are heavily recruited during weightlifting exercise [99]
The aim of this review was to provide an up-to-date summary of data from experimental studies that have examined the efficacy of dietary

Summary

Introduction

Weightlifting exercise is well established as an exercise modality of resistance exercise to improve skeletal muscle mass [1,2], strength [3,4,5], endurance [6,7] and power [8,9]. These positive adaptations in skeletal muscle function translate into athletic performance [10,11,12,13,14] and health-related [15,16,17,18,19] benefits in a range of populations [20,21,22]. Static methods include isometric muscle strength assessments to evaluate maximal voluntary isometric contraction (MVIC)

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