Tan Rachel, Lincoln Isabella G, Paniagua Keonabelle K, Foster Justin M, Wideen Lauren E, Gerardo Raymond T, Ornelas Nathan J, Tchaprazian Isaac, Li Jeffrey, Egiazarian Michael, Rowland Samantha N, Bailey Stephen J, Pennell Adam
Department of Sports Medicine, Natural Sciences Division, Pepperdine University, 24255 Pacific Coast Highway, Malibu, CA, 90263, USA.
School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
Eur J Appl Physiol. 2025 Apr 24. doi: 10.1007/s00421-025-05779-1.
Dietary nitrate (NO) can enhance skeletal muscle contractile function and explosive-type exercise by modulating type II muscle fibers; however, limited attention has been directed at exploring the optimal dosing guidelines and potential performance-enhancing effects of NO supplementation during resistance-type exercise. The purpose of our investigation was to examine potential dose-response effects of concentrated NO-rich beetroot juice on neuromuscular performance during resistance exercise. Eighteen resistance-trained men were assigned in a double-blind, randomized, crossover design, to four conditions to consume beetroot juice containing: negligible NO (PL); ~ 6 mmol NO (BR-LOW); ~ 12 mmol NO (BR-MOD); and ~ 24 mmol NO (BR-HIGH). Participants completed 1 set of vertical countermovement jumps (CMJ), 2 sets × 3 repetitions of barbell back squats, and 2 sets × 3 repetitions of barbell bench press 2.5 h post-supplementation. Plasma [NO] increased in a dose-dependent manner (P < 0.01). Plasma [nitrite] ([NO]) increased in all BR conditions compared to PL (P < 0.05), such that BR-MOD vs. BR-LOW (P < 0.01) and BR-LOW vs. PL (P < 0.01), but BR-HIGH was not different compared to BR-MOD (P > 0.05). Performance was not different between conditions in CMJ, 50% one-repetition maximum (1RM) and 75%1RM back squats, or 50%1RM and 75%1RM bench press (P > 0.05). The change in plasma [NO] was significantly correlated with peak power (r = - 0.65, P = 0.003), mean power (r = - 0.52, P = 0.03), and mean velocity (r = - 0.48, P = 0.04) during 50%1RM back squats following BR-LOW vs. PL but not in other conditions (P > 0.05). This study indicates that dietary NO does not impact resistance exercise performance at any of the doses assessed in the current study.
膳食硝酸盐（NO）可通过调节II型肌纤维来增强骨骼肌收缩功能和爆发性运动；然而，在抗阻训练期间，探索最佳剂量指南和补充NO的潜在性能增强效果的研究较少。我们研究的目的是检查富含NO的浓缩甜菜根汁在抗阻训练期间对神经肌肉性能的潜在剂量反应效应。18名经过抗阻训练的男性被分配到四个组，采用双盲、随机、交叉设计，分别饮用含有可忽略不计的NO（PL）、约6 mmol NO（BR-LOW）、约12 mmol NO（BR-MOD）和约24 mmol NO（BR-HIGH）的甜菜根汁。参与者在补充后2.5小时完成1组垂直纵跳（CMJ）、2组×3次杠铃后深蹲和2组×3次杠铃卧推。血浆[NO]呈剂量依赖性增加（P<0.01）。与PL相比，所有BR组的血浆[亚硝酸盐]（[NO]）均增加（P<0.05），BR-MOD与BR-LOW相比（P<0.01），BR-LOW与PL相比（P<0.01），但BR-HIGH与BR-MOD相比无差异（P>0.05）。CMJ、50%一次重复最大值（1RM）和75%1RM后深蹲或50%1RM和75%1RM卧推的各条件下性能无差异（P>0.05）。在BR-LOW与PL相比后，50%1RM后深蹲期间血浆[NO]的变化与峰值功率（r=-0.65，P=0.003）、平均功率（r=-0.52，P=0.03）和平均速度（r=-0.48，P=0.04）显著相关，但在其他条件下无相关性（P>0.05）。本研究表明，在本研究评估的任何剂量下，膳食NO均不影响抗阻训练表现。
