To examine the effect of acute beetroot juice supplementation on the rate of fatigue as measured by changes in peak torque. Placebo-controlled, double-blind, cross-over study, 35 recreationally active subjects consumed beetroot (BR) juice or black currant juice (PL) 12 and 2.5 hours before the exercise procedure. Peak torque was measured on the BIODEX dynamometer by performing 50, maximal effort, concentric knee extensions at 90°/s. Blood pressure (BP) was recorded before and after exercise. No significant difference between BR and PL in the rate of fatigue measured by change in peak torque. By stage 3, subjects retained 87.6±6.9% of strength with BR and 86.7±6.3% with PL (p= 0.363). Stages 10 was as follows: BR 47.9±12.6 vs. PL 46.9±12.9% (p= 0.419). The rate of work fatigue showed no significant differences. By stage 4, mean percent work fatigue showed 20.6±9% with BR and 21.8±10.1% with PL (p= 0.224). Stage 10 was as follows: BR 52.5±12.6% vs. PL 53.2±13% (p= 0.571). Post-exercise diastolic BP (BR: 67.2±9.8 vs. PL: 64.5±7.9mmHg, p= 0.039) and MAP (BR: 91.6±9.3 vs. PL: 88.8±8.2mmHg, p= 0.011) were higher with BR supplementation. Acute bouts of beetroot juice supplementation had no significant effect on knee extensor muscle fatigue measured during isokinetic contractions