Nitrate supplementation and elite sport performance

The main objective of the current study is to assess the impact of nitrate supplementation on sports performance in elite athletes. The study will be conducted in a randomized crossover manner, consisting of two intervention periods of 6 days (either nitrate-rich beetroot juice or nitrate-depleted placebo beetroot juice). This will be investigated in five different sub studies:



Sub study A: The effect of dietary nitrate supplementation on elite team sport performance

Sub study B: The effect of dietary nitrate supplementation on elite high-intensity cycling performance

Sub study C: The effect of dietary nitrate supplementation on elite rowing performance

Sub study D: The effect of dietary nitrate supplementation on elite swimming performance

Sub study E: The effect of dietary nitrate supplementation on elite badminton performance

The difference in performance between the nitrate and placebo intervention will be investigated.

Dietary nitrate supplementation enhances exercise performance of elite athletes competing in intermittent and high-intensity sport disciplines.

Subjects participate in a screening session, a familiarization test (to practice the performance test), and two test days. During the test days blood samples will be taken twice (at baseline and 2.5 h following ingestion of the last nitrate supplement) and the performance test is conducted approximately 3 h following the last supplementation bolus.

The study consists of five sub studies, all applying the same intervention. The intervention comprises two 6-day supplementation periods either with 140 ml concentrated beetroot juice (containing 800 mg NO3) or 140 ml placebo beetroot juice (nitrate-depleted), supplemented in a randomized crossover manner. The interventions will be separated by a wash-out period of at least 1 week. Sport specific exercise performance tests will be conducted after each 6-day supplementation period. The performance test will be different for the five different sub studies;

A. YoYo IRT for team sports (or other team sport specific performance test); the subjects perform an time to exhaustion test consisting of 2x 20 m shuttles at increasing speed, interfered by a 10 s recovery period between each shuttle. The subject runs until he/she cannot perform the shuttle within the given time, and the total distance covered is the performance outcome.

B: Wingate cycling test; a 30 s all out cycling sprint for short high-intensity sport disciplines (i.e. track cycling, short track ice skating). The performance outcome is the peak and average power output.

C: Rowing ergometer performance test; a 2000 m time trial on a slide II rowing ergometer. The performance outcomes are time to completion and power output.

D: Swimming performance test; a swimming step test consisting of 5x 200 m swimming at increasing intensity. The performance outcomes are time to complete each 200 m and each 100 m split time.

E: Badminton specific performance test; a change-of-direction speed test performed four times. The performance outcome is the average time to completion of the two best runs.

Amendment 12-okt-2016: Concentrated beetrootjuice (both nitrate-rich and placebo) will be used as supplement (not natriumnitrate)