Dietary Nitrate Ingestion Does Not Improve Neuromuscular Performance in Male Sport Climbers

Abstract

Beetroot juice (BJ) is commonly used as an ergogenic aid in endurance and team sports, however, the effect of this supplement on climbing performance is barely studied. The purpose of the current study was to investigate the effect of acute BJ ingestion on neuromuscular and biochemical variables in amateur male sport climbers. Ten physically active sport climbers (28.8 ± 3.7 years) underwent a battery of neuromuscular tests consisting of the half crimp test, the pull-up to failure test, the isometric handgrip strength test, the countermovement jump (CMJ) and the squat jump (SJ). Participants performed the neuromuscular test battery twice in a cross-over design separated by 10 days, 150 min after having consumed either 70-mL of BJ (6.4 mmol NO3-) or a 70-mL placebo (0.0034 mmol NO3-). In addition, nitrate (NO3-) and nitrite (NO2-) saliva concentrations were analysed, and a side effect questionnaire related to ingestion was administrated. No differences were reported in particular neuromuscular variables measured such as the CMJ (p = 0.960; ES = 0.03), the SJ (p = 0.581; ES = −0.25), isometric handgrip strength (dominant/non dominant) (p = 0.459–0.447; ES = 0.34–0.35), the pull-up failure test (p = 0.272; ES = 0.51) or the maximal isometric half crimp test (p = 0.521–0.824; ES = 0.10–0.28). Salivary NO3- and NO2- increased significantly post BJ supplementation compared to the placebo (p < 0.001), while no side effects associated to ingestion were reported (p = 0.330–1.000) between conditions (BJ/placebo ingestion). Acute dietary nitrate supplementation (70-mL) did not produce any statistically significant improvement in neuromuscular performance or side effects in amateur sport climbers.