Neuromuscular Performance Clinical Trial
Malate or Not?: Effects of L-Citrulline or Citrulline-malate on Neuromuscular Performance in Resistance-trained Adults
The main aim of this study is to compare the effects of L-Citrulline vs. Citrulline-malate on neuromuscular performance (maximal dynamic strength and maximal endurance strength) in resistance-trained adults.
Nitric oxide (NO) is a ubiquitous gaseous molecule that plays a critical role in the regulation of cardiovascular function and in the signaling of multiple cellular processes. Specifically, NO could reduce the oxygen cost of exercise and adenosine triphosphate (ATP) in the production of muscle contractile force, improving calcium handling, glucose uptake and mitochondrial efficiency in muscle fibers. Therefore, it has been suggested that increasing the availability of NO through the oral intake of food and nutritional supplements may be useful to delay the onset of fatigue and improve performance in high-intensity efforts. L-citrulline is a nonessential amino acid involved in the urea cycle that acts as an endogenous precursor of L-arginine, being a more efficient alternative to L-arginine to increase the plasma concentration of L-arginine through the nitric oxide synthase (NOS) pathway. On the other hand, citrulline malate is an organic salt of L-citrulline and malate which has been shown to exert a small but significant ergogenic effect in different high-intensity efforts compared to a placebo. However, no study to date has compared L-citrulline VS. citrulline malate to assess whether there is an additive effect from malate to exercise performance. 50 resistance-trained adults (50% women) will be randomized into three conditions (L-citrulline, citrulline-malate and placebo conditions) with 48 hours of separation between conditions. 48h previous to the randomization the participants will perform a familiarization to avoid the learning effects. Each evaluation day will conform to the following tests: - Maximal dynamic strength of lower- and upper-body - Maximal endurance strength of lower- and upper-body ;