Coggan, Andrew R.Broadstreet, Seth R.Mikhalkova, DeanaBole, IndraLeibowitz, Joshua L.Kadkhodayan, AnaPark, SooThomas, Deepak P.Thies, DakkotaPeterson, Linda R.2018-12-182018-12-182018-01-25Coggan, A. R., Broadstreet, S. R., Mikhalkova, D., Bole, I., Leibowitz, J. L., Kadkhodayan, A., … Peterson, L. R. (2018). Dietary nitrate‐induced increases in human muscle power: high versus low responders. Physiological Reports, 6(2). https://doi.org/10.14814/phy2.135752051-817Xhttps://hdl.handle.net/1805/18002Maximal neuromuscular power is an important determinant of athletic performance and also quality of life, independence, and perhaps even mortality in patient populations. We have shown that dietary nitrate (NO 3 −), a source of nitric oxide (NO), improves muscle power in some, but not all, subjects. The present investigation was designed to identify factors contributing to this interindividual variability. Healthy men (n = 13) and women (n = 7) 22–79 year of age and weighing 52.1–114.9 kg were studied using a randomized, double‐blind, placebo‐controlled, crossover design. Subjects were tested 2 h after ingesting beetroot juice (BRJ) either containing or devoid of 12.3 ± 0.8 mmol of NO 3 −. Plasma NO 3 − and nitrite (NO 2 −) were measured as indicators of NO bioavailability and maximal knee extensor speed (V max), power (P max), and fatigability were determined via isokinetic dynamometry. On average, dietary NO 3 − increased (P < 0.05) P max by 4.4 ± 8.1%. Individual changes, however, ranged from −9.6 to +26.8%. This interindividual variability was not significantly correlated with age, body mass (inverse of NO 3 − dose per kg), body mass index (surrogate for body composition) or placebo trial V max or fatigue index (in vivo indicators of muscle fiber type distribution). In contrast, the relative increase in Pmax was significantly correlated (r = 0.60; P < 0.01) with the relative increase in plasma NO 2 − concentration. In multivariable analysis female sex also tended (P = 0.08) to be associated with a greater increase in Pmax. We conclude that the magnitude of the dietary NO 3 −‐induced increase in muscle power is dependent upon the magnitude of the resulting increase in plasma NO 2 − and possibly female sex.en-USAttribution 3.0 United StatesFiber typeisokinetic dynamometrynitric oxidesex differencesArticle