Impact of Augmenting Exercise Intensity vs. Frequency

Study Overview
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Brief Summary
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The purpose of this study is to compare the impact of augmenting exercise intensity and augmenting exercise frequency on peak work rate. Participants will complete exercise tests and provide 8 skeletal muscle samples following a within-subjects randomized crossover design utilizing single-leg cycling. Both training periods will be 4 weeks long and skeletal muscle biopsies will be collected from both legs before and after each training period. All exercise sessions will be supervised, take place in the investigator's laboratory, and occur on stationary bikes.

Official Title
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Impact of Augmenting Exercise Intensity vs. Frequency on Peak Work Rate

Conditions
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Exercise Training

Intervention / Treatment
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* Behavioral: Frequency comparison
* Behavioral: Intensity comparison


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Recreational active (<3 hours per week of aerobic exercise) Willing to provide skeletal muscle biopsies Exclusion Criteria: Cardiovascular or metabolic disease Athletes or individuals exceeding 3 hours per week of aerobic exercise Smokers

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 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: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Frequency then Intensity<br>Training period 1: Frequency comparison Training period 2: Intensity comparison | Behavioral: Frequency comparison<br>* One leg assigned to low-frequency low-intensity (3 days per week of 11 x 1 min @ 73% peak work rate interspersed with 1-minute periods of active recovery). The other leg assigned to high-frequency low-intensity (5 days per week of 11 x 1 min @ 73% peak work rate interspersed with 1-minute periods of active recovery).<br>Behavioral: Intensity comparison<br>* One leg assigned to low-frequency low-intensity (3 days per week of 11 x 1 min @ 73% peak work rate interspersed with 1-minute periods of active recovery). The other leg assigned to low-frequency high-intensity (3 days per week of 8 x 1 min @ 100% peak work rate interspersed with 1-minute periods of active recovery).<br>|
| Experimental: Intensity then Frequency<br>Training period 1: Intensity comparison Training period 2: Frequency comparison | Behavioral: Frequency comparison<br>* One leg assigned to low-frequency low-intensity (3 days per week of 11 x 1 min @ 73% peak work rate interspersed with 1-minute periods of active recovery). The other leg assigned to high-frequency low-intensity (5 days per week of 11 x 1 min @ 73% peak work rate interspersed with 1-minute periods of active recovery).<br>Behavioral: Intensity comparison<br>* One leg assigned to low-frequency low-intensity (3 days per week of 11 x 1 min @ 73% peak work rate interspersed with 1-minute periods of active recovery). The other leg assigned to low-frequency high-intensity (3 days per week of 8 x 1 min @ 100% peak work rate interspersed with 1-minute periods of active recovery).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak work rate | Change in Highest work rate achieved (30s period) during incremental exercise tests | Before exercise training on two days ( 7 and 6 days before first training session;  24 hours apart), and after exercise on two days ( 48-96 hours after the last training session;  24 hours apart) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak oxygen uptake | Change in Highest oxygen uptake achieved (30s period) during incremental exercise tests | Before exercise training on two days ( 7 and 6 days before first training session;  24 hours apart), and after exercise on two days ( 48-96 hours after the last training session;  24 hours apart) | 
| Maximal citrate synthase activity | Change in maximal citrate synthase activity | Before exercise training ( 7 days before first training session), and after exercise training ( 48-72 hours after the last training session) |