Effects of L-Arginine and Citrulline Malate Supplementation on Sport Performance in Physically Active Men

NCT ID: NCT06938126

Last Updated: 2025-04-22

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 46 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-10-01
• Study Completion Date: 2024-09-30

Brief Summary

In this randomized, double-blind, placebo-controlled trial we investigated the effects of combined L-arginine (Arg) and citrulline-malate (CM) supplementation on aerobic, anaerobic, and high-intensity interval training in healthy, physically active men. 46 healthy, physically active men were divided into three distinct exercise protocol groups: CrossFit group, the Wingate Anaerobic Test group, and the Harvard Step Test group. The CrossFit performance assessment involved the "Cindy" workout, a high-intensity protocol composed of bodyweight exercises organized in a set sequence: 5 pull-ups, 10 push-ups, and 15 squats. Participants were instructed to perform as many rounds as possible within 20 minutes. The Wingate Anaerobic test involved a 30-second all-out cycling test on a bike ergometer, while the Harvard Step Test The Harvard Step Test was conducted using a 51 cm high platform, with participants stepping at a rate of 30 steps per minute (one second up, one second down) for five minutes or until exhaustion. Each participant attended three separate laboratory sessions. The initial session served for familiarization with the test protocol to minimize learning effects. In the second and the third sessions, participants attended two measurement sessions, conducted in randomized order and under double-blind conditions, where they received either the dietary supplementation or a placebo. Each participant acted as their control, allowing for within-subject comparisons.

Detailed Description

Consumption of dietary supplements is a common strategy among athletes aiming to optimize recovery after training or competitions and enhance athletic performance. Amino acids L-arginine (Arg) and L-citrulline (Cit) are two of the most widely used supplements in recent times. Their use as nutritional supplements or dietary supplements to improve health and athletic performance has increased dramatically, as both Arg and Cit are essential for the body's synthesis of nitric oxide (NO) and elimination of waste products such as lactate during physical activity. Because it functions as an endogenous precursor to Arg, the primary substrate of nitric oxide, Cit, a non-protein, non-essential amino acid, has attracted a lot of attention lately for its potential to improve exercise performance. Commonly, citrulline is consumed as citrulline malate (CM), which is a mixture of Cit and malic acid in ratios ranging from 1:1 to 2:1. The combined intake of Arg and CM could potentially enhance athletic performance more effectively than using either supplement alone. This synergistic benefit is attributed to Cit's role in synthesizing additional Arg, which in turn elevates NO production, enhancing blood flow and possibly reducing muscle fatigue. Supporting this hypothesis, mixed supplementation of Arg and CM was examined in a previous study and significant increases in both force exertion and fatigue resistance during a 10-minute high-intensity cycling test was found. However, while initial evidence suggests potential ergogenic benefits of combined Arg and CM supplementation, further research is needed to confirm these effects across various exercise modalities. The aim of this study was to investigate the acute effects of combined Arg and CM supplementation on anaerobic performance, aerobic performance, or both through high-intensity interval training (i.e. CrossFit) outcomes in healthy, physically active men. Based on existing research, it was hypothesized that the supplementation would enhance performance by achieving higher peak power in the anaerobic protocol and CrossFit in the CrossFit training protocol, where rapid energy production and resistance to fatigue are critical.

Conditions

Healthy

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: OTHER
• Blinding Strategy: DOUBLE

Study Groups

Supplementation

Supplementation of L-Arginine and Citrulline-malate as a liquid

Group Type: EXPERIMENTAL

L-Arginine and Citrulline-Malate Supplementation

Intervention Type: DIETARY_SUPPLEMENT

L-Arginine and Citrulline Malate supplementation was consumed as a liquid one single time to examine the acute effects on sport performance

Placebo

Consumption of a placebo liquid

Group Type: PLACEBO_COMPARATOR

Placebo consumption

Intervention Type: DIETARY_SUPPLEMENT

Consumption of placebo as a liquid

Interventions

L-Arginine and Citrulline-Malate Supplementation

L-Arginine and Citrulline Malate supplementation was consumed as a liquid one single time to examine the acute effects on sport performance

Intervention Type: DIETARY_SUPPLEMENT

Placebo consumption

Consumption of placebo as a liquid

Intervention Type: DIETARY_SUPPLEMENT

Eligibility Criteria

Inclusion Criteria

• being healthy, physically active with no history of injuries or illnesses at the time of measurement or within the preceding six months

Exclusion Criteria

• consumption of any dietary supplements in the last six months to avoid confounding effects

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 30 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

Hungarian University of Sports Science

OTHER

Sponsor Role: lead

Responsible Party

Leonidas Petridis

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Hungaria University of Sports Science

Budapest, , Hungary

Countries

Hungary

Study Documents

Document Type: Individual Participant Data Set

For more information please email to: petridis.leonidas@tf.hu

View Document

Related Links

https://tf.hu/en/

Home page of the University of Sports Science

Other Identifiers

HungarianUSportsScience

Identifier Type: OTHER

Identifier Source: secondary_id

TE-KEB/22/2023

Identifier Type: -

Identifier Source: org_study_id