Esen Ozcan, Dobbin Nick, Callaghan Michael J
Department of Health Professions, Manchester Metropolitan University, Manchester, UK.
Manchester Metropolitan University Institute of Sport, Manchester, UK.
J Am Nutr Assoc. 2023 May-Jun;42(4):327-338. doi: 10.1080/07315724.2022.2037475. Epub 2022 May 23.
The propose of this study was to systematically review the current literature and meta-analyse the effects of dietary nitrate (NO) supplementation on the contractile properties of skeletal muscle. A literature search of three databases was conducted in June 2021, with 19 studies meeting the inclusion criteria. Studies were included if a placebo versus dietary NO-only supplementation protocol was used in healthy human, assessed muscle contraction or activities that was < 3 minutes in duration and focused on the lower-body. For the meta-analysis, a pooled standardised mean difference (SMD) was determined for maximum voluntary contraction (MVC) ( = 11), cycling, running and inertial load squad peak power output (PPO) ( 8), mean power output (MPO) ( = 6) and time to PPO ( = 4). NO supplementation demonstrated a small improvement in PPO (SMD = 0.25, = 0.030) and MPO (SMD = 0.28, = 0.030) when compared to the placebo. NO also resulted in an enhanced time to PPO (SMD = -0.78, < 0.001). There was no clear effect of NO on isometric MVC (SMD = 0.03, = 0.758). This review reports that NO supplementation may have potential to enhance PPO, MPO and time to PPO during dynamic exercise, which may transfer to brief explosive actions commonly observed in sporting activities. Due to the variability in studies, we encourage researchers to use this work to explore areas where evidence in lacking and standardize the study design and procedures.Key teaching pointsFindings from this meta-analysis highlight the potential positive ergogenic effect of dietary NO3-supplementation on PPO, MPO and time to PPO during short duration (<10 s) dynamic exercise.NO3- supplementation might be considered as an ergogenic aid when executing power-based actions (e.g., 100 m sprinter or weightlifter).This review highlights that further research is required to address some of the contrasting findings presented here using a standardised procedure to allow for improved synthesis.
本研究的目的是系统回顾当前文献，并对膳食硝酸盐（NO）补充剂对骨骼肌收缩特性的影响进行荟萃分析。2021年6月对三个数据库进行了文献检索，有19项研究符合纳入标准。如果在健康人群中使用安慰剂与仅补充膳食NO的方案，评估持续时间<3分钟的肌肉收缩或活动，并关注下半身，则纳入研究。对于荟萃分析，确定了最大自主收缩（MVC）（n = 11）、骑自行车、跑步和惯性负荷深蹲峰值功率输出（PPO）（n = 8）、平均功率输出（MPO）（n = 6）和达到PPO的时间（n = 4）的合并标准化平均差（SMD）。与安慰剂相比，补充NO后PPO（SMD = 0.25，P = 0.030）和MPO（SMD = 0.28，P = 0.030）有小幅改善。NO还使达到PPO的时间延长（SMD = -0.78，P < 0.001）。NO对等长MVC没有明显影响（SMD = 0.03，P = 0.758）。本综述报告称，补充NO可能有潜力在动态运动中提高PPO、MPO和达到PPO的时间，这可能转化为体育活动中常见的短暂爆发性动作。由于研究存在变异性，我们鼓励研究人员利用这项工作探索证据不足的领域，并规范研究设计和程序。关键知识点本荟萃分析的结果突出了膳食补充NO3对短时间（<10秒）动态运动中的PPO、MPO和达到PPO的时间具有潜在的积极促力作用。在执行基于力量的动作（如100米短跑运动员或举重运动员）时，补充NO3可被视为一种促力辅助手段。本综述强调，需要进一步研究以使用标准化程序解决此处呈现的一些相互矛盾的结果，以便进行更好的综合分析。
