Influence of Varying Doses and Duration of Dietary Nitrates from Beetroot Juice on Sprint Performance in U.S. Army ROTC Cadets: A pilot study

Abstract

Objective: Assess the effects of varying levels and duration of dietary nitrate supplementationfrom beetroot juice (BR) on sprint performance in army ROTC cadets. Methods: Army Reserve Officer Training Corps (ROTC) cadets were randomly assigned to oneof three treatment groups: control (CON); low beetroot juice dose (BR1); and high BR juice –BR2. For 0, 6 and 15 days nitrate consumption from BR groups were as follows: CON receivedone 16.9 oz. bottle of apple juice (0 mg NO 3 -); BR1 received one can of BR juice (300 mg, 4.84mmol NO 3 -), and BR2 received 2 cans (16.8 oz.) BR (600 mg, 9.68 mmol NO 3 -). One week priorto the study, each cadet completed body composition measurements, predicted aerobic capacitymeasurements, and nutritional analysis via two 24-hour dietary recalls. Differences in primarymeasures (distance covered in the Yo-Yo IR1) were analyzed with two-way repeated measuresANOVA tests both between groups (CON, BR1, BR2) and within groups (0, 6, and day 15).Descriptive statistics and frequency counts were run on all remaining variables with a one-wayANOVA or t-test, including maximal heart rate during the YoYo IR1, dietary compliance, dailyblood pressure, juice compliance, and conditioning work-outs Results: A dose-related enhancement with BR was observed; the data trended towardssignificance even in this small sample. A t-test revealed that there was a significant difference insprint performance by males and females overall at days 0, 6, 15 (p = 0.025, p = 0.005, p =0.004, respectively). Conclusion: A single (300 mg, 4.84 mmol NO 3 ) or double (600 mg, 9.68 mmol NO 3 -) daily doseconsumption of BR appears to benefit ROTC cadets in athletic performance. Daily consumptionof BR benefitted ROTC males more than females. Results suggest BR supplementation could beadvantageous for sprint performance when administered for a longer duration (> 15 days).