Protein Requirements Amongst Male Masters-Level Athletes Following a Cycling Exercise Bout as Determined by the Indicator Amino Acid Oxidation Technique

Masters level cyclists are a population above the age of 35 years who frequently participate in prolonged as well as heavy-volume training. Like most endurance-trained athletes, a greater recommended dietary allowance (RDA) for protein of 1.2-1.4 g/kg/bw is suggested.

Dietary protein intake is vital for maximizing the benefits of training and ensuring optimal recovery. Dietary recommendations traditionally have been determined through nitrogen balance techniques, however, recent research indicates how this method is potentially underestimating protein requirements. Therefore, there is a need to reassess current dietary recommendations in order to meet the demands of physical activity for highly active populations.

Recent efforts to understand protein requirements during rest and following exercise have been completed using the indicator amino acid technique (IAAO). This non-invasive method is reported to provide a robust measure of protein requirements. However, there is limited work in older (≥60 years) active populations.

The purpose of this study is to measure the protein requirements in master cyclists, following an endurance training session, using the non-invasive IAAO technique.

Study Overview

• Status: Recruiting
• Conditions: Healthy; Increased Metabolic Requirements; Dietary Reference Intakes
• Intervention / Treatment: Dietary supplement: Amino Acid Intake

• Study Type: Interventional
• Enrollment (Estimated): 8
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tyler A. Churchward-Venne, Ph.D.; Phone Number: 00839 (514) 398-4184; Email: tyler.churchward-venne@mcgill.ca
• Study Contact Backup: Name: Damian Papadopoulos, B.Sc; Phone Number: (514) 561-7860; Email: damian.papadopoulos@mail.mcgill.ca

Study Locations

• Canada
  • Quebec
    • Montreal, Quebec, Canada, H3A 0G4
      • Recruiting
      • McGill University
      • Contact: Tyler Churchward-Venne, PhD; Phone Number: (514) 399-9684; Email: tyler.churchward-venne@mcgill.ca
      • Principal Investigator: Tyler Churchward-Venne, PhD
      • Sub-Investigator: Damian Papadopoulos, BSc
      • Contact: Damian Papadopoulos, B.Sc.; Phone Number: 5145617860; Email: damian.papadopoulos@mail.mcgill.ca

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 18.5< BMI <35 kg/m^2
• Overtly healthy masters level cyclists ≥65 years
• Masters level cyclist training (>4 days per week; ~100 km per week)
• Body mass stable over previous 6-months
• Availability for multiple metabolic trials (~7 trials)
• Ability to travel to and from laboratory facility

Exclusion Criteria:

• Recent history of weight loss or weight gain (>5% body weight)
• Uncontrolled hypertension
• ≥2 chronic diseases (e.g. diabetes, osteoporosis, dyslipidemia)
• Acute illness that could affect protein metabolism (HIV, renal dysfunction, influenza)
• Currently using anti-inflammatory medications
• Inability to adhere to study protocol (i.e., alcohol, caffeine, dietary restrictions)
• Regular tobacco user
• Illicit drug use
• Habitually ingesting ≥3 g/kg/bw

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Masters Level Cyclists; Participants are to be randomly assigned varying levels of amino acid intakes ranging between 0.2 to 2.8 g/kg/d	Dietary supplement: Amino Acid Intake; Amino acid intakes will vary between 0.2 to 2.8 g/kg/d

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
13CO2 Excretion	Measured by continuous-flow isotope ratio mass spectrometry	7-weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
L[13C]phenylalanine Oxidation	Measured by gas chromatography-mass spectrometry	7-weeks

Collaborators and Investigators

• Sponsor: McGill University

Study record dates

Study Major Dates

• Study Start (Actual): June 21, 2024
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): June 1, 2026

Study Registration Dates

• First Submitted: May 22, 2024
• First Submitted That Met QC Criteria: May 22, 2024
• First Posted (Actual): May 28, 2024

Study Record Updates

• Last Update Posted (Actual): February 9, 2026
• Last Update Submitted That Met QC Criteria: February 5, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: A06-M25-23A

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No