Exercise Dose-response and Protein Requirements

Study Overview
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Brief Summary
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Study will investigate the impact of training volume on protein metabolism to estimate the impact on daily protein requirements of endurance athletes.

Official Title
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Dose Response Effect of Endurance Exercise on Protein Requirements of Endurance Athletes

Conditions
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Exercise Training

Intervention / Treatment
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* Other: Endurance exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy, male, endurance-trained participants who regularly run more than 40 km/week or perform endurance exercise for more than 4.5 hours/week Participants who have a self-reported 5-km run time of ≤23 min Participants who are categorized as at least very good based on a study by Shvartz & Reibold (Shvartz 1990), in which VO2peak is used as an index. (i.e. the participants whose VO2peak is ≥57 ml/kg/min (18-24 y), ≥54 ml/kg/min (25-29 y), ≥52 ml/kg/min (30-34 y), ≥49 ml/kg/min (35-39 y) Ability to complete the 16-km familiarization run on Session 2 Aged 18-40 years old Exclusion Criteria: - Inability to meet health and physical activity guidelines according to the PAR-Q+ (The Physical Activity Readiness Questionnaire for everyone; Appendix 1). Female: hormonal fluctuations associated with the menstrual cycle have been reported to alter protein metabolism during exercise (Moore, Camera, Areta, and Hawley, 2014; Hamadeh, Devries, and Tarnopolsky 2005) and may influence specific amino acid requirements at rest (Kriengsinyos, Wykes, Goonewardene, Ball, and Pencharz 2004); as such, the present study will test the effect of endurance exercise on protein requirements in males only to ensure a stable hormonal environment and to increase the homogeneity of the physiological response. Nevertheless, given that WHO/FAO protein requirements are provided independently of sex and that recommendations for protein intake in athletes generally do not distinguish between the sexes (American Dietetic A, Dietitians of C, American College of Sports, Rodriguez, Di Marco, and Langley, 2009) or that protein requirements have been reported to be lower in endurance trained females than males (Rowland and Wadswortt, 2011), it could also be argued that protein requirements determined by IAAO would be similar between the sexes and/or potential reduced in females. Therefore, to investigate the effect of endurance exercise on protein requirements, we will test males as an indication of the potentially greatest protein requirement between the sexes. (NOTE: we pan to be test females in a future trial based off of the results obtained herein) Inability to adhere to any of the protocol guidelines (i.e. alcohol, caffeine consumption) Regular tobacco use (screened by survey sheet for training log (Appendix 2)) Illicit drug use (e.g. growth hormone, testosterone, etc.)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Nonexercised rested day<br>Athlete will not exercise on trial day. | Other: Endurance exercise<br>* On the trial day before commencing the indicator amino acid oxidation metabolic trial, participants will either rest, perform a 10km run on a treadmill, or perform a 20km run on a treadmill.<br>|
| Experimental: Recovery from 10KM run<br>Athlete will run 10km on trial day. | Other: Endurance exercise<br>* On the trial day before commencing the indicator amino acid oxidation metabolic trial, participants will either rest, perform a 10km run on a treadmill, or perform a 20km run on a treadmill.<br>|
| Experimental: Recovery from 20KM run<br>Athlete will run 20km on trial day. | Other: Endurance exercise<br>* On the trial day before commencing the indicator amino acid oxidation metabolic trial, participants will either rest, perform a 10km run on a treadmill, or perform a 20km run on a treadmill.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Phenylalanine excretion | Excretion of 13CO2 in the breath will be used to estimate the impact of exercise on daily protein requirements. This outcome will include the enrichment of 13CO2 in exhaled breath after the ingestion of [13C]phenylalanine tracer and the production of CO2 determined by indirect calorimetry at rest or after exercise. | 8 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Phenylalanine flux | The enrichment of [13C]phenylalanine in the urine will be used to estimate the flux of phenylalanine in the body at rest or after exercise. | 8 hours | 
| Phenylalanine oxidation | The oxidation of [13C]phenylalanine will be determined by correcting phenylalanine excretion by phenylalanine flux. | 8 hours |