The Effect of Inorganic Nitrate Supplementation on Muscle Fatigue in Healthy Adults; A Meta-Analysis

다국어 초록 (Multilingual Abstract)

Abstract: The positive effects of dietary supplementation with beetroot juice have been
reported on diverse aspects of sports performance, but its impact on muscle fatigue
remains unclear.
Purpose: The purpose of this meta-analysis is to investigate the effect of beetroot juice
supplement on muscle fatigue assessed by changes in strength or power outputs.
Methods: Through the comprehensive search using major databases, 215 relevant studies
were identified. Three search terms were used to identify potentially relevant articles;
“Beetroot” AND “Exercise” AND “Fatigue.” Several moderator analyses were conducted to
examine the effect of dosage, timing of supplementation, type of measure, gender, and
participation on the overall effect size.
Results: The results showed a significant positive effect of beetroot juice supplementation
on muscle fatigue: the overall strength of ESs (Hedges’ g) was .334 (95% CI = .149, .520, p
< .001; moderate effects; cf., Cohen’s criteria). The prediction interval was -.925 to 1.593,
indicating that there are some populations for which the impact of beetroot juice on fatigue
would be negative. There was no significant effect of moderators (participation (athletes
vs. non-athletes), duration of supplement consumption, NO3
− concentration, gender, and
type of measurement (power vs. strength) on the size of the effect.
Conclusion: This study shows that dietary beetroot juice supplementation significantly
reduces fatigue indicated by a decline in strength and power outputs.