1. The effects of nitrate supplementation on Yo-Yo intermittent recovery test performance with female university level athletes
Fiona McGinnes1, Melissa Bargh1, and Geoff Middleton1
School of Sport and Exercise Science, University of Lincoln, Lincoln, UK1
INTRODUCTION
METHOD
DISCUSSION
Nitric Oxide (NO) is a recognised mechanism underpinning a variety of performance enhancements (Figure 1; Hoon, 2014).
Ten female university students (M age 21 ± 1.3 years, stature ± 7.6 cm, body mass ± 5.78 kg) who participated in a variety of university sports (e.g., football, rowing, swimming) recreationally and competitively took part in the study (Figure 2).
NO3­ – supplementation significantly reduced VO2max, extending time to exhaustion in the YYIR1. This supports previous research, which found that NO3­ – supplementation reduces exercise cost and increases exercise efficiency (Jones et al., 2010).
Dietary inorganic nitrate (NO3­ –) can improve muscle efficiency and endurance exercise tolerance, in addition to modulating resting blood pressure and energy metabolism (Kapil et al., 2010).
Measurements were obtained for: (i) resting heart rate (HR) pre-test; (ii) BL, HR and rate of perceived exertion (RPE) at the end of each stage interval (IV - IV1 = 5.1km/h; IV2 = 9.1km/h; IV3 = 11.2km/h; IV4 = 12.3km/h); and (iii) HR and BL immediately, four, and eight minutes post-test.
The mechanisms behind this adaptation could include increased mitochondrial and muscle contractile efficiency, and improved vascular control and blood flow (Zaferidis, 2014).
NO3­ – supplementation in the form of beetroot juice (BR) has been reported to significantly decrease exercising blood lactate (BL), which enhances metabolic control and exercise efficiency (Jones, Poole, Grassi & Christensen, 2010).
Practical Applications
NO3­ – supplementation through BR can improve performance in female athletes participating in high- intensity, intermittent sports. The 10.85% mean increase in performance found could be valuable to athletes, extending time to exhaustion.
Generally, research has been directed towards continuous exercise within the male population (James, Willis, Allen, Winyard and Jones, 2015), with limited research examining the effect of nitrate utilisation performance in high intensity intermittent exercise among female university students.
Improvements in BL could be beneficial in the later stages of performance to prevent the onset of fatigue.  
Future directions
Chronic supplementation - ~6.4 mmol a day, 4-6 days.
Figure 2. Illustration of study protocol.
Testing in an outside environment, with a portable gas analysis system.
RESULTS
Direct plasma measurement through saliva samples using highly-trained athletes.
NO3­ – supplementation demonstrated a significant effect (effect size = 1.19; p = .004) on VO2max as measured by distance covered in the YYIR1 (M diff = 10.85%).
Figure 1. Pathway of NO production.
Although greater in the PLAC trial, NO3­ – supplementation had no significant effect on HR (M decrease during test +1.6 bpm; M decrease post-test +9.6 bpm; p =.697 ), BL (M difference = Lab; p =.697 ) or RPE (M diff = -0.31, p > 0.05), (ηp2= 0.96, 0.92, 0.17 respectively).
AIM
REFERENCES
Hoon, M. W., Jones, A. M., Johnson, N. A., Blackwell, J. R., Broad, E. M., Lundy, B., ... & Burke, L. M. (2014). The effect of variable doses of inorganic nitrate-rich beetroot juice on simulated 2000-m rowing performance in trained athletes. International journal of sports physiology and performance, 9(4),
To assess the physiological and performance effects of dietary nitrate supplementation (BEET; ~6.4 mmol, 70ml) on maximal, exhaustive intermittent exercise during Bangsbo’s intermittent recovery test level 1 (YYIR1) in comparison to a placebo (PLAC; ~0.04 mmol, 70ml).
James, P. E., Willis, G. R., Allen, J. D., Winyard, P. G., & Jones, A. M. (2015). Nitrate pharmacokinetics: Taking note of the difference. Nitric Oxide, 48,
Jones, A. M., Poole, D. C., Grassi, B., & Christensen, P. M. (2010). The slow component of VO2 kinetics: mechanistic bases and practical applications. Healthy Learning.
Kapil, V., Milsom, A. B., Okorie, M., Maleki-Toyserkani, S., Akram, F., Rehman, F., ... & MacAllister, R. (2010). Inorganic nitrate supplementation lowers blood pressure in humans: role for nitrite-derived NO. Hypertension, 56(2),
Zafeiridis, A. (2014). The effects of dietary nitrate (beetroot juice) supplementation on exercise performance: A review. American Journal of Sports Science, 2(4),
Ethical approval granted
Test familiarisation
Random assignment
BEET or PLAC ingestion
Bangsbo’s Intermittent Yo-Yo recovery test (YYIR1)
≥7 Day crossover
Data analysis
2.5 hour rest
2.5 hour rest