Citrulline malate has no effect on German Volume Training Protocol - abstract only

Citrulline malate (CM) is purported to improve aerobic and anaerobic exercise performance through a variety of mechanisms including: improved ammonia metabolism, lactate buffering, increased vasodilation and increased adenosine triphosphate production. In a double-blind, placebo controlled, crossover trial 15 healthy, resistance trained individuals (11 men, 4 women) consumed either 8 g of CM or a placebo one hour before participating in a German Volume Training (GVT) exercise protocol. The GVT protocol consisted of 10 sets of 10 repetitions of single leg, leg extensions, with one minutes rest between sets using an isokinetic dynamometer. Each set was ended when full range of motion could no longer be achieved; the number of repetitions achieved across the 10 sets was main outcome measure. Blood samples were taken at baseline and post GVT for blood lactate analysis. The effect of the GVT protocol on post-exercise isometric maximal voluntary contraction (MVC) and selfreported muscle soreness up to 72 h after exercise were measured. A repeated measures ANOVA was used to analyse the number of completed repetitions and muscle soreness. The change in lactate and isometric MVC at baseline to post exercise was assessed using a paired samples t-test. Citrulline malate administration had no effect on the total number of repetitions achieved during the GVT protocol (CM: 90.9 ± 13.9 reps, Placebo: 94.0 ± 7.9 reps, P = 0.34), or on post-exercise isometric MVC (Baseline: 208.2 ± 70.9 CM: 213.1 ± 80.3 Nm, Placebo: 206.2 ± 55.4 Nm, P = 0.24). Blood lactate concentrations increased between baseline and post-exercise (P = 0.01), but there was no difference (P = 0.47) in the pre- to post-exercise lactate between treatment conditions (pre: CM: 1.7 mM± 1.1, Placebo: 1.5 ± 0.5 mM; post CM: 4.2 ± 1.3 mM, Placebo: 4.3 ± 1.3 mM). Finally, self-reported mean muscle soreness after exercise was greater (P = 0.01) under the CM treatment (combined soreness score 248 ± 90) compared to the Placebo (combined mean VAS score 150 ± 70). The loading and timing of the dose of CM may have consequences for performance outcomes, but results of this research indicate that an 8 gram acute dose of CM does not provide an ergogenic benefit for trained males and females.