Supportive effects of beetroot juice on sporting results questioned by

The study examines the effect of beetroot juice on endurance running performance. The results indicate that 70-ml nitrate-rich beetroot juice taken 2.5 hr prior to time trials does not improve competitive 5-km time-trial performance in amateur runners compared with placebo. 

Source: https://journals.humankinetics.com/view/journals/ijsnem/30/4/article-p295.xml