The Effect of Acute and Chronic L-Citrulline and Citrulline Malate Supplementation on Resistance Training Performance, Muscle Soreness, Lactate and Nitric Oxide in Resistance-Trained Men

Investigating the effects of acute and chronic supplementation with L-citrulline compared to citrulline malate on resistance training performance, muscle contusion, lactate and nitric oxide

In the acute phase, in a double-blind cross-over and counter-balanced placebo-controlled design, Each subject randomly receives one of the 3 supplement interventions. Blood sampling will be done before and after each session, and factors related to resistance training performance will also be recorded in each session. In the chronic phase, in the form of a randomized, double-blind, placebo-controlled design, 45 resistance trained male volunteers will be randomly divided into three groups of 15 (g 1: L-citrulline, g 2: citrulline malate, and g 3: placebo) and will follow a resistance training protocol for eight weeks, along with receiving the relevant supplement. Before and after the eight-week protocol, a one maximum repetition testing session for the hack squat and chest press exercises is performed in order to evaluate the effect of the supplement intervention on the lower and upper body strength.

Research sessions will be held in: Acute phase: Prime Cross Fit Club (Kermanshah, Iran) Chronic phase: Iran Fit gym (Kermanshah, Iran)

Inclusion criteria: History of resistance training at least 3 sessions per week in the last 6 months Body mass index 18.5 to 29.99 (kg/m2) Entry ban criteria: Smoking Current or past use of anabolic androgenic steroids Consuming performance-enhancing supplements affecting research results

1. L-citrulline (8 grams of L-citrulline + 15 grams of maltodextrin) 2) Citrulline malate (12 grams of citrulline malate + 15 grams of maltodextrin) 3) Placebo (15 grams of maltodextrin)

Maximum strength; Muscular endurance; Nitric oxide; Lactate

For the acute phase, due to the inclusion of three conditions (L-Citrulline, Citrulline malate, and Placebo), there were six possible sequences in which participants could complete the study (i.e. ABC, ACB, BAC, BCA, CAB and CBA). Based on the sample size (n = 30), each sequence will be used exactly five times. The order in which the sequences is assigned to participants will be determined using Random Sequence Generator at WWW.RANDOM.ORG website. For the chronic phase, according to the existence of three groups (L-citrulline, citrulline malate, and placebo), all subjects (n=45) will be divided into three equal groups (15 subjects in each group) using a table of random numbers and will be placed in one of the groups in a simple random way.

In the acute phase, the main researchers and all the people involved in data collection will be blinded to the type of intervention (supplement) given to each subject in each of the three main research sessions. To achieve this, the random assignment of the subjects in the counter-balance table and the preparation of the supplements provided to the subjects in each session are done by a research assistant who will not be present at the time of taking the supplement intervention at the research site and will not be involved in any part of the data collection process. Also, in order to keep the subjects blind, the supplement consumed by each subject in each research session is prepared by one of the research assistants and given to the subject to consume in a dark colored shaker whose contents are not known. In addition, the subject should also use a nose clip while drinking this mixture. Similar to the acute phase, in the chronic phase, the main researchers and all the people involved in data collection are unaware of the type of intervention received by each subject during the eight weeks of exercise and supplementation protocol. To achieve this, random assignment of subjects to three groups is done by a research assistant who does not interfere in other stages of this research plan. Also, the supplement consumed by the subjects of all three groups is also prepared by the same research assistant. The supplement provided to the subjects of all three groups will be similar in terms of smell and taste.