1. Results Figure 2 – RPE during the 3000 m TTs Figure 3 – TT Performance time between experimental trials. BR supplementation did not significantly improve TT performance. (P=0.811 between baseline and BR trials, P=1.00 between baseline and PL and P=1.00 between PL and BR). Mean RPE showed no significant difference between BR and PL (P=1.00). There was a difference between baseline and BR (P=0.02) and no difference between baseline and PL (P=0.06). There was no significant difference between mean HR over the trials (P=1.00). Acute dietary nitrate supplementation does not improve 3000 m running performance in trained male endurance athletes. Clare Twaddle, Rachael Dawe & Lisa Board Department of Sport and Exercise, Faculty of Applied Sciences, University of Sunderland, Sunderland SR1 3SD. Introduction The ergogenic benefits of dietary nitrate supplementation (in the form of beetroot juice, BR) on sporting performance has received extensive research interest. BR ingestion has been shown to reduce the oxygen cost of sub-maximal exercise, improve exercise tolerance and enhance performance in moderately trained athletes. More recently, others have suggested individual aerobic fitness affects the ergogenic benefits induced by dietary nitrate supplementation. In elite athletes or those with higher levels of aerobic fitness BR supplementation had shown limited effect on 3000 m (Porcelli, et al., 2014), 1500 m running performance (Boorsma, et al., 2014) or elite cross-country skiers (Peacock, et al., 2012). Few studies have evaluated time trial (TT) running performance in an ecologically valid setting i.e. on the outdoor running track. This study aimed to investigate the short-term effects of acute BR supplementation on 3000 m TT performance in trained endurance runners. The study attempted to measure physiological responses and running performance in a simulated competitive environment. Athletes complete the experimental trials in groups with athletes of similar running ability, increasing ecological validity. The study was granted ethical approval by the University of Sunderland. Method Research Design – Randomised, double blind, placebo-controlled, cross-over design. Figure 1 – Schematic representation of research design Participants - 8 apparently healthy, trained male participants (mean ± s: age 34 ± 12 years, body mass 58.5 ± 25.5 kg, stature 1.74 ± 0.26 m, maximal oxygen uptake (V ̇ O 2 max ) 65.05 ± 7.68 ml·kg −1 ·min −1, personal best for 3000 m 9:28 ± 1:24 min:sec) Experimental Protocol – Participants completed 3 x 3000m running time trials (TT) on an outdoor running track. Prior to experimental trials, participants ingested a 70 mL beetroot juice beverage (Beet-it Juice, James White Drinks Ltd, Ipswich, UK). The drink consumed in the control trial was a placebo [active ingredient (NO 3- ) removed]. In the dietary nitrate trial participants consumed a similar drink but which contained the active ingredient (0.3 g NO 3- ). All drinks looked, smelled and tasted the same. Participants told to run each TT as fast as possible as if in competition and wanting to win.. Measures - HR and RPE recorded at 3 minute intervals. Prior to experimental trials exercise and food diaries were recorded for 24hrs and replicated. Sleep quality was recorded through a sleep quality questionnaire. Hydration status was measured using specific gravity and osmolality prior to each treatment trial. Data analysis – Data presented as mean ±s. Normality of data checked using a Kolmogorov-Smirnov test. A one way repeated measures ANOVA was used for analysis. References Porcelli, S., Ramaglia, M., Bellistri, G., Pavei, G., Pugliese, L., Montorsi, M., Rasica, L., Marzorati, M.. (2014). Aerobic Fitness Affects the Exercise Performance Responses to Nitrate Supplementation. Medicine and Science in Sports & Exercise. [Epub ahead of print].. Boorsma, R.K., Whitfield, J. & Spriet L.L. (2014) Beetroot juice supplementation does not imporve performance of elite 1500-m runners. Medicine and Science in Sports & Exercise, 46(12):2326-34. Peacock, O., Tiønna, A.E., James, P., Wisløff, U., Welde, B., Böhlke, N., Smith, A., Stokes, K., Cook, C. & Sandbakk, O.(2012) Dietary nitrate does not enhance running performance in elite cross-country skiers. Medicine and Science in Sports & Exercise, 44(11):2213-9. Conclusion Acute dietary nitrate supplementation in the form of BR juice (70mL) had no effect on 3000m time trial performance in well trained, male endurance athletes. Control (n=4)Dietary Nitrate (n=5) Baseline 3000 m Control (n=4) Dietary Nitrate (n=5)