Effect of Citrulline and Creatine supplementation on physical performance in healthy young adults

INTERVENTION: A randomized, double‐blind, placebo‐controlled, parallel‐group clinical trial will be conducted to investigate the effects of isolated and combined supplementation of citrulline malate and creatine monohydrate on maximal strength performance, isometric strength, muscular endurance, muscular power, and perceived exertion and pain. In the first session, participants will undergo familiarization with the testing protocol; additionally, anthropometric and body composition measurements will be taken, and questionnaires regarding physical activity level, weekly supplement consumption, 24‐hour dietary recall, sleep quality assessment, and physical and mental readiness will be administered. This familiarization session will take place 7 days prior to the experimental session. The experimental session is characterized by 7 days of supplementation. On the first day (D1) and seventh day (D7) of the experimental session, muscular strength, endurance, and power tests will be performed, and the measurements and questionnaires administered during familiarization will be repeated. Participants will be randomized and assigned to one of the following groups: G1 ‐ isolated citrulline malate (Cit), G2 ‐ isolated creatine monohydrate (Cre), G3 ‐ combined citrulline malate and creatine monohydrate (CitCre), or G4 ‐ placebo (Plac). Each group will consist of 5 individuals, totaling 20 individuals at the end of the experiment. For each group, the 7‐day supplementation or placebo will be provided to participants 24 hours prior to the start of the testing protocol. Participants will be instructed to avoid alcohol, caffeine, and strenuous exercise for 24 hours before visiting the laboratory. They will also be instructed not to alter their dietary intake and fluid consumption habits throughout the entire experiment. The order of the tests will be randomized using the randomizer.com platform. To ensure blinding, all sachets will be visually identical and isovolumetric. Maltodextrin will be used as an excipient for weight‐matching in the groups not receiving the active ingredients, ensuring that all participants ingest the same total amount of powder daily. In addition, a lemon‐flavored sweetener and flavoring will be added to all samples. The equalization of sachet volume and weight was chosen over strict caloric equalization. To ensure isovolumetric conditions, G1 will receive: 4 sachets containing 5g of maltodextrin and 1 sachet containing 8g of Cit. G2 will receive: 4 sachets containing 5g of Cr and 1 sachet containing 8g of maltodextrin. G3 will receive: 4 sachets containing 5g of Cr and 1 sachet containing 8g of Cit. G4 will receive 4 sachets with 5g of maltodextrin and 1 sachet with 8g of maltodextrin. That is, all groups will receive four 5g sachets and one 8g sachet; since the 8g sachet will be the one containing citrulline (in the case of G1 and G3), all participants will be instructed to ingest this sachet 60 minutes before training. CONDITION: Dietary Supplements; physical functional performance ; Amino Acids, Peptides, and Proteins PRIMARY OUTCOME: To assess physical performance in tests of muscle strength, power, and endurance using an isokinetic dynamometer, in order to analyze the effects of isolated and combined supplementation of citrulline malate and creatine monohydrate on muscle strength, power, and endurance SECONDARY OUTCOME: No secondary outcomes are expected INCLUSION CRITERIA: Aged between 18 and 45 years; Have at least 12 months of resistance training experience; Currently performing resistance training at least three times per week; with a minimum of 3 months of continuous activity