Department of Allied Health Sciences, Human Movement Science Curriculum, University of North Carolina, Chapel Hill, North Carolina.
Department of Exercise and Sport Science, Applied Physiology Laboratory, University of North Carolina, Chapel Hill, North Carolina.
J Strength Cond Res. 2019 Sep;33(9):2321-2329. doi: 10.1519/JSC.0000000000003286.
Trexler, ET, Keith, DS, Schwartz, TA, Ryan, ED, Stoner, L, Persky, AM, and Smith-Ryan, AE. Effects of citrulline malate and beetroot juice supplementation on blood flow, energy metabolism, and performance during maximum effort leg extension exercise. J Strength Cond Res 33(9): 2321-2329, 2019-Citrulline malate (CitMal) and beetroot juice (BEET) are increasingly popular ergogenic aids, but few studies have rigorously investigated their effects on resistance exercise performance and underlying mechanisms. The current randomized, double-blind, crossover study evaluated the effects of CitMal and BEET supplementation on blood flow, metabolic efficiency, and performance during maximal isokinetic leg extension exercise. After familiarization, 27 recreationally active men (age: 22 ± 4 years) completed 3 visits in which subjects ingested a treatment beverage (CitMal [8 g], BEET [400-mg nitrate], or placebo [PLA]), followed by a 2-hour rest period, warm-up, and 5 sets of 30 concentric leg extensions. Before and after exercise, ultrasound was used to measure diameter (aDIAM) and blood flow (aBF) of the superficial femoral artery, along with cross-sectional area and echo intensity of the vastus lateralis. Plasma analytes (lactate, nitrate/nitrite [NOx], and urea nitrogen [BUN]) were also assessed at these times, and indirect calorimetry was used to measure energy expenditure and respiratory exchange ratio before and during exercise. Resting NOx values were higher in BEET (233.2 ± 1.1 μmol·L) compared with CitMal (15.3 ± 1.1, p < 0.0001) and PLA (13.4 ± 1.1, p < 0.0001). Postexercise NOx values, adjusted for resting differences, were higher in BEET (86.3 ± 1.2 μmol·L) than CitMal (21.3 ± 1.1, p < 0.0001) and PLA (18.1 ± 1.1, p < 0.0001). No other variables were affected by treatment (all p > 0.05). While BEET increased NOx, neither treatment was found to enhance performance, blood flow, metabolic efficiency, nor the hormonal response to leg extension exercise.
特雷勒，ET，基思，DS，施瓦茨，TA，瑞安，ED，斯通纳，L，珀斯基，AM，和史密斯 - 瑞安，AE。瓜氨酸苹果酸盐和甜菜根汁补充剂对最大努力腿部伸展运动中的血液流动、能量代谢和性能的影响。J 力量与调节研究 33（9）：2321-2329，2019-瓜氨酸苹果酸盐（CitMal）和甜菜根汁（BEET）是越来越受欢迎的运动补剂，但很少有研究严格调查它们对阻力运动表现和潜在机制的影响。当前的随机、双盲、交叉研究评估了 CitMal 和 BEET 补充剂对最大等速腿部伸展运动中血液流动、代谢效率和性能的影响。在熟悉之后，27 名有经验的男性（年龄：22 ± 4 岁）完成了 3 次访问，其中受试者摄入了治疗饮料（CitMal [8 g]，BEET [400-mg 硝酸盐]或安慰剂 [PLA]），随后是 2 小时的休息时间、热身和 5 组 30 次向心腿部伸展运动。在运动前后，使用超声测量股浅动脉的直径（aDIAM）和血流量（aBF），以及股外侧肌的横截面积和回声强度。还在这些时间点评估了血浆分析物（乳酸、硝酸盐/亚硝酸盐[NOx]和尿素氮[BUN]），并在运动前后使用间接量热法测量能量消耗和呼吸交换比。与 CitMal（15.3 ± 1.1，p < 0.0001）和 PLA（13.4 ± 1.1，p < 0.0001）相比，BEET（233.2 ± 1.1 μmol·L）的静息 NOx 值更高。调整静息差异后的运动后 NOx 值在 BEET（86.3 ± 1.2 μmol·L）中高于 CitMal（21.3 ± 1.1，p < 0.0001）和 PLA（18.1 ± 1.1，p < 0.0001）。没有其他变量受治疗影响（p > 0.05）。虽然 BEET 增加了 NOx，但两种治疗方法都没有被发现能提高性能、血液流动、代谢效率或腿部伸展运动的激素反应。
