Nitrate (${\mathrm{NO}}_3^{-}$) has properties that can improve muscle function, leading to improvements in metabolic cost of exercise as well as enhance force production. Gymnastics is a whole-body sport, involving events that demand a high level of strength and fatigue resistance. However, the effect of ${\mathrm{NO}}_3^{-}$ supplementation on both upper- and lower-body function in gymnasts is unknown. This study examined the effect of acute beetroot juice (BRJ) supplementation on isokinetic strength and endurance of the upper- and lower-body in highly trained international-level male gymnasts. In a double-blind, randomized crossover design, 10 international-level male gymnasts completed two acute supplementation periods, consuming either 2 × 70 ml ${\mathrm{NO}}_3^{-}$-rich (∼12.8 mmol/L of ${\mathrm{NO}}_3^{-}$) or ${\mathrm{NO}}_3^{-}$-depleted (PLA) BRJ. Maximal strength of the upper-leg and upper-arm at 60°/s, 120°/s, 180°/s, and 300°/s, and muscular endurance (50 repeated isokinetic contractions at 180°/s) were assessed. Plasma ${\mathrm{NO}}_3^{-}$ (BRJ: 663 ± 164 μM, PLA: 89 ± 48 μM) and nitrite (${\mathrm{NO}}_2^{-}$) concentrations (BRJ: 410 ± 137 nmol/L, PLA: 125 ± 36 nmol/L) were elevated following BRJ compared to PLA (both p < .001). Maximal strength of knee and elbow extensors and flexors did not differ between supplements (p > .05 for all velocities). Similarly, fatigue index of knee and elbow extension and flexion was not different between supplements (all p > .05). Acute BRJ supplementation, containing ∼12.8 mmol/L of ${\mathrm{NO}}_3^{-}$, increased plasma ${\mathrm{NO}}_3^{-}$ and ${\mathrm{NO}}_2^{-}$ concentrations, but did not enhance isokinetic strength or fatigue resistance of either upper or lower extremities in international-level male gymnasts.

硝酸盐（${不}_3^{-}$）具有可以改善肌肉功能的特性，从而改善运动的代谢成本并增强力量的产生。体操是一项全身运动，涉及需要高水平力量和抗疲劳能力的项目。然而，效果${不}_3^{-}$对体操运动员上半身和下半身功能的补充尚不清楚。本研究探讨了急性甜菜根汁 (BRJ) 补充剂对训练有素的国际级男子体操运动员上半身和下半身等速力量和耐力的影响。在双盲、随机交叉设计中，10 名国际级男子体操运动员完成了两个急性补充期，消耗 2 × 70 毫升${不}_3^{-}$-富含（~12.8 mmol/L${不}_3^{-}$） 或者${不}_3^{-}$-耗尽（PLA）BRJ。评估大腿和上臂在 60°/s、120°/s、180°/s 和 300°/s 时的最大力量，以及肌肉耐力（以 180°/s 重复 50 次等速收缩）。等离子体${不}_3^{-}$（BRJ：663 ± 164 μM，PLA：89 ± 48 μM）和亚硝酸盐（${不}_2^{-}$与 PLA 相比，BRJ 后浓度（BRJ：410 ± 137 nmol/L，PLA：125 ± 36 nmol/L）升高（均p  < .001）。不同补充剂之间膝、肘伸肌和屈肌的最大力量没有差异（所有速度下p  > 0.05）。同样，不同补充剂之间膝盖和肘部伸展和弯曲的疲劳指数没有差异（所有p  > 0.05）。急性 BRJ 补充剂，含有 ∼12.8 mmol/L${不}_3^{-}$, 增加血浆${不}_3^{-}$和${不}_2^{-}$浓度，但并没有增强国际级男子体操运动员上肢或下肢的等速力量或抗疲劳能力。