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

February 5, 2026 updated by: Tyler Churchward-Venne, McGill University

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

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

8

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Canada
    • Quebec
      • Montreal, Quebec, Canada, H3A 0G4
        • Recruiting
        • McGill University
        • Contact:
        • Principal Investigator:
          • Tyler Churchward-Venne, PhD
        • Sub-Investigator:
          • Damian Papadopoulos, BSc
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

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
Time Frame: 7-weeks
Measured by continuous-flow isotope ratio mass spectrometry
7-weeks

Secondary Outcome Measures

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

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

McGill University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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