Table 1.

PICOS criteria.

Parameter	Inclusion Criteria
Participant	Recreationally active, healthy adult males and females, aged 18–65 years.
Intervention	Nitrate supplementation provided as beetroot juice without contiguous ingestion of other supplements, and information was provided on the supplementation dose, timing, frequency, and vehicle of administration.
Comparator	Placebo provided as beetroot juice with negligible nitrate content.
Outcomes	Performance outcomes of peak power, mean power, time-to-peak power, minimum power, and total work done during bouts of 30-s high-intensity sprints.
Study Design	Randomized, double-blinded, crossover, placebo-controlled trials. Only studies that were published in English and as original research (i.e., not a conference abstract or review) were included.