Effect of Protein Quality During Overreaching in Trained Cyclists

Study Overview
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Brief Summary
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Athletes frequently undertake periods of intensified training commonly referred to as overreaching. These training periods acutely decrease performance, with the expectation that performance will rebound and improve after a short recovery. Yet, overreaching does not always improve performance and may be a precursor to overtraining syndrome, a long-term decrement in performance. A nutritional intervention focused on the adoption of 'best practices' for protein feeding (optimal timing, dose, and quality) could help reduce the stress of overreaching, reduce the likelihood of developing overtraining syndrome, and augment adaptations to intensified exercise. While the nutrition study is our main interest, the investigators first want to validate the measurement of exercise performance. Accordingly, this project consists of two related studies: (1) the assessment of short time trials for reliability and validity; and (2) the assessment of optimal protein feeding to decrease the stress of overreaching and improve outcomes following training.

Detailed Description
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Endurance-trained athletes frequently undergo periods of overreaching (increased training loads) to improve performance. In study 1, the investigators will determine whether 4-min and 20-min time trials are repeatable and whether they (individually or collectively) relate to 1-hour time trial performance. For Study 2, the investigators propose that proper nutrition (with a focus on the dose, timing, and quality of protein) can help mitigate the stress of overreaching, which will improve performance. Thus, the investigators will compare the effects of two diets that differ in terms of protein servings (dose, timing, quality). In Study 2, skeletal muscle biopsies will be collected to determine how dietary protein intervention impacts the quality and quantity of skeletal muscle mitochondria in response to intense training. For study 1, the objective is to determine the reliability and validity of 4-min and 20-min time trial performance (mean power output). For study 2, the objective is to (1) determine whether following an optimal protein diet during a period of intense training will, relative to a typical diet: (1) improve measures of exercise performance, (2) improve sleep quality, psychological wellbeing, and immune function, (3) improve the quality and quantity of skeletal muscle mitochondria. Study 1 is a reliability and validity experiment designed to assess the key outcome measure in study 2. Study 2 is a randomized, crossover study. Participants will, in a randomized order, complete both conditions, separated by a 4-day washout period.

Official Title
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Monitoring Exercise Performance and Mitigating Training Stress in Endurance-trained Cyclists

Conditions
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Muscle Protein Synthesis

Intervention / Treatment
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* Dietary Supplement: Alpha-lactalbumin
* Dietary Supplement: Collagen peptides


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: non-smokers non-diabetic Participants had to be training regularly (performing aerobic exercise at least 4 times per week, including regular cycling exercise) Generally healthy Exclusion Criteria: consuming excessive alcohol (>21 units per week) use of an investigational drug or nutraceutical in the previous 30 days dairy allergy history of significant loss or gain of body mass in the past 6 months (>2kg) regular use of non-steroidal anti-inflammatory drugs infectious disease, and/or the presence of any relevant disease (e.g., gastrointestinal, cardiovascular, neuromuscular, 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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All

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: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Randomized cross-over design
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Alpha-lactalbumin<br>Participants will consume 60 g of alphalactalbumin (fraction of whey protein) for 3 training days. | Dietary Supplement: Alpha-lactalbumin<br>* A protein fraction of whey protein, higher in tryptophan<br>|
| Active Comparator: Collagen peptides<br>Participants will consume 60 g of collagen peptides for 3 training days. | Dietary Supplement: Collagen peptides<br>* Collagen peptides from bovine sources<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of myofibrillar muscle protein synthesis | Rate of myofibrillar and protein synthesis (%/day) | 12 days | 
| Rate of Sarcoplasmic muscle protein synthesis | Rate of sarcoplasmic muscle protein synthesis (%/day) | 12 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma amino acids | Measurement of plasma amino acids 1 hour following ingestion of each beverage | 1 x 1 hour | 
| Sleep efficiency (%) | Measured by Actigraphy | 12 days | 
| Sleep fragmentation | Measured by Actigraphy | 12 days | 
| Wake after sleep onset (WASO) in minutes | Measured by Actigraphy | 12 days | 
| Total sleep time (min) | Measured by Actigraphy | 12 days |