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Completed

NCT Number: NCT04855474

Protein Requirements in Male and Female Endurance Athletes

Protein is an essential macronutrient for post-exercise recovery through its ability to provide the amino acid building blocks that support increased rates of muscle and whole body protein synthesis.

Despite the growing understanding of the importance of post-exercise protein in endurance athlete populations, the impact of sex and female menstrual cycle phase on protein metabolism is not fully understood. To date, no studies have examined protein requirements in female endurance trained athletes.

The aim of the proposed study is to utilize the well-established IAAO method to determine protein requirements in endurance trained female and male athletes in a "real-world" and at-home setting.

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Key information

Conditions

Increased Metabolic Requirement Healthy

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Goldring Centre for High Performance Sport

Toronto, Ontario, M5S2C9, Canada

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy endurance trained runners. Total weekly running distance of greater than 50km/week and perform endurance exercise for more than 5 hours/week.
  • Age 18-35 years old
  • Eumenorrheic over last 3 months (one cycle no longer than 42 days and no shorter than 20 days).
  • Not using hormonal contraceptives (the pill, implants and injections, hormonal intrauterine devices (IUDs), vaginal ring, skin patch).
  • Do not have polycystic ovarian syndrome (PCOS) or other conditions effecting ovarian hormone regularity.
  • Not pregnant within the past year.
  • Must meet the classification of 'superior' aerobic power for their respective age category based on the ACSM criteria; (women age 20-29 years VO2max >50ml/kg/min and women age 30-35 years VO2max >46ml/kg/min) (men age 20-29 years VO2max >56ml/kg/min and men age 30-35 years VO2max >54ml/kg/min).

Exclusion criteria

  • Inability to meet health and physical activity guidelines according to the CSEP 'Get Active' Questionnaire (Appendix G).
  • Inability to adhere to study protocol requirements relating to diet and exercise (i.e. alcohol and caffeine consumption, training/exercise prior to beginning a study testing day).
  • Regular use of tobacco and/or other recreational drugs/banned substances (i.e. growth hormone, testosterone, marijuana).
  • Self-reported intentional or unintentional weight loss (past 6 months) or plan to lose weight (>5-10kg).
  • Amenorrhea (self-reported) in the past 3 months.
  • Fewer than 6 menstrual cycles per year.
  • Answering yes to any questions asked within the COVID-19 screening questionnaire until 14 days of being symptom free and/or having a negative COVID-19 test

Treatment and study plan

Amino acid intake

Dietary Supplement

Participants will consume hourly (8 hours) isoenergetic, isonitrogenous beverages containing one of the three protein intakes (0.2g/kg/d, 1.2 g/kg/d, 2.0g/kg/d) assigned in a randomized order between the three metabolic trials. Drinks will be enriched with stable isotope [13C]phenylalanine. The use of stable isotope [13C]phenylalanine will allow for the determination of the fate of AA in the body (incorporation into body protein or oxidation) which can be used to determine protein (AA) requirements.

Primary outcomes

  1. Phenylalanine excretion

    Time frame: 8 hours

    13CO2 production in umol/kg/h

Secondary outcomes

  1. Phenylalanine Oxidation

    Time frame: 8 hours

    [13C]phenylalanine oxidation in umol/kg/h

  2. Phenylalanine net balance

    Time frame: 8 hours

    Difference between phenylalanine rate of appearance and disappearance

Other outcomes

  1. Urinary 3-methylhistidine

    Time frame: 8 hours

    Concentration of urine 3-methylhistidine

  2. Protein requirement

    Time frame: 8 hours

    Estimated breakpoint of phenylalanine excretion, phenylalanine oxidation, and phenylalanine net balance

Sponsors and collaborators

Lead sponsor

University of Toronto

Other

Registry information

Official study title

Estimating Post-exercise Protein Requirements in Male and Female Endurance Athletes

Important dates

Study start
2021
Primary completion
2021
Study completion
2022
First posted
Apr 22, 2021
Registry last updated
Jul 13, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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