Effects of Dietary Nitrate Supplementation on Performance and Muscle Oxygenation during Resistance Exercise in Men

• Published in: Nutrients 2022-09, Vol.14 (18), p.3703
• Main Authors: Tan, Rachel, Pennell, Adam, Price, Katherine M, Karl, Sean T, Seekamp-Hicks, Noelle G, Paniagua, Keonabelle K, Weiderman, Grant D, Powell, Joanna P, Sharabidze, Luka K, Lincoln, Isabella G, Kim, Justin M, Espinoza, Madeleine F, Hammer, Maya A, Goulding, Richie P, Bailey, Stephen J
• Format: Article
• Language: English
• Subjects: beetroot; Beets; Beta vulgaris; Comparative analysis; Cross-Over Studies; Dietary Supplements; Double-Blind Method; Exercise; Health aspects; Humans; Ingestion; Laboratories; Male; Metabolism; Muscles; Musculoskeletal system; neuromuscular; Nitrates; Nitrates - pharmacology; nitric oxide; Nitrites; Nitrogen Dioxide; Nitrogen Oxides; Nutritional aspects; Oxygenation; Physical fitness; Physiological aspects; Physiology; Power; Quadriceps Muscle; Resistance Training; Saturation index; Strength training; Strengthening exercises; Sugar beets; Velocity; weightlifting
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu14183703

The purpose of the current study was to assess the effects of acute and short-term nitrate (NO3−)-rich beetroot juice (BR) supplementation on performance outcomes and muscle oxygenation during bench press and back squat exercise. Fourteen recreationally active males were assigned in a randomized, double-blind, crossover design to supplement for 4 days in two conditions: (1) NO3−-depleted beetroot juice (PL; 0.10 mmol NO3− per day) and (2) BR (11.8 mmol NO3− per day). On days 1 and 4 of the supplementation periods, participants completed 2 sets of 2 × 70%1RM interspersed by 2 min of recovery, followed by one set of repetitions-to-failure (RTF) at 60%1RM for the determination of muscular power, velocity, and endurance. Quadriceps and pectoralis major tissue saturation index (TSI) were measured throughout exercise. Plasma [NO3−] and nitrite ([NO2−]) were higher after 1 and 4 days of supplementation with BR compared to PL (p < 0.05). Quadriceps and pectoralis major TSI were not different between conditions (p > 0.05). The number of RTF in bench press was 5% greater after acute BR ingestion compared to PL (PL: 23 ± 4 vs. BR: 24 ± 5, p < 0.05). There were no differences between BR and PL for RTF for back squat or power and velocity for back squat or bench press (p > 0.05). These data improve understanding on the ergogenic potential of BR supplementation during resistance exercise.