Effects of L-Citrulline or Citrulline-malate on Neuromuscular Performance in Resistance-trained Adults

Study Overview
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Brief Summary
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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.

Detailed Description
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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

Official Title
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Malate or Not?: Effects of L-Citrulline or Citrulline-malate on Neuromuscular Performance in Resistance-trained Adults

Conditions
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Neuromuscular Performance

Intervention / Treatment
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* Dietary Supplement: L-citrulline
* Dietary Supplement: Citrulline-malate
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy male or female Ages 18-30years BMI: 18-30.0 kg/m2 Stable weight over the last 3 months (body weight changes<3kg) Previous experience in resistance training (i.e., at least 1 year with a frequency of two or more training sessions per week), Participant must be capable and willing to provide consent, understand exclusion criteria, instructions and protocols. Exclusion Criteria: History of chronic diseases (renal disease, diabetes, cardiovascular disease, cancer, VIH, hepatic disease, food disorders) Pregnant, planning to become pregnant, or breastfeeding Have been treated previously or during the study period with prescription drugs: antihypertensive, lipid lowering, acid uric lowering, glucose lowering, beta blockers or any drug that under the investigator's judged could influence the results. Allergy/intolerance to any ingredient of the dietary supplements. Chronic consumers of dietary NO-precursors dietary supplements (citrulline malate, arginine, nitrates). Any non-controlled medical condition which could influence results or could be worsened by the participation in the study. Are deemed unsuitable by the investigator for any other reason, that prevent data collection.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental: L-Citrulline<br>5 g of L-citruline + 5 g of additives. The dose to be administered is that recommended on the labeling and nutritional information of the product, which has been produced under GMP procedures and approved by the EFSA (Lifepro®). | Dietary Supplement: L-citrulline<br>* 5 g of L-citruline + 5 g of additives<br>|
| Experimental: Experimental: Citrulline-malate<br>8g of citrulline-malate + 2 g of additives. The dose to be administered is that recommended on the labeling and nutritional information of the products which has been produced under GMP procedures and approved by the EFSA (Lifepro®). | Dietary Supplement: Citrulline-malate<br>* 8g of citrulline-malate + 2 g of additives<br>|
| Placebo Comparator: Placebo<br>10g of maltodextrin plus additives (Lifepro®). | Dietary Supplement: Placebo<br>* 10g of maltodextrine<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maximal endurance strength | Maximal endurance strength of lower- and upper-body (squat and bench press exercises) | 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maximal dynamic strength | Maximal dynamic strength of lower- and upper-body (squat and bench press exercises) | 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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nitric oxide, dietary supplement, resistance training, citrulline malate