Role of Mechanical Load on Metabolic Exercise Adaptations in Response to Weight Loss in Obese Adolescents: The POWELL Study

Study Overview
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Brief Summary
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While interdisciplinary weight loss intervention have been shown successful among adolescents with obesity, a weight regain is most of the time observed within the following weeks or months. The aim of the present project will be to better identify the independent role played by both the metabolic and mechanical load and their modification during weight loss, on the energy expenditure and energy metabolism of adolescents with obesity.

Detailed Description
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A total of 28 adolescents with obesity will be recruited from our local inpatient pediatric obesity centers. Before their weight loss intervention the adolescents will complete two experimental visits. During the first visit, anthropometric and body composition measurements will be performed. Then the participants will be asked to complete a walking exercise on a treadmill during the second visit. Their energy expenditure and substrate oxidation will be assessed by indirect calorimetry. They will have to walk at 5 different walking speeds. Then, they will follow a 12-week weight loss intervention. By the end of this intervention, their body composition will be assessed and they will be asked to perform the same walking exercise. On a separate occasion (randomly assigned) they will have to repeat this walking exercise while carrying a load corresponding of their weight loss.

Official Title
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Role of Mechanical Load on Metabolic Exercise Adaptations in Response to Weight Loss in Obese Adolescents: The POWELL Study

Conditions
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Pediatric Obesity

Intervention / Treatment
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* Behavioral: Multidisciplinary weight loss


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: being aged 12-16 years old no contraindication to physical exercise no cardiovascular disease BMI above the 97th percentile candidate to a weight loss intervention Exclusion Criteria: surgery and medical conditions preventing them to perform the intervention Weight loss during the previous 6 months medication that could interfere with energy metabolism. pregnancy regular tobacco and alcool use

Ages Eligible for Study
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Minimum Age: 12 Years
Maximum Age: 16 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Interventional Model Description: One group of adolescents with obesity
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Adolescents with obesity<br>Adolescents with obesity aged 12-16 years old | Behavioral: Multidisciplinary weight loss<br>* The adolescents will follow a 12-week intervention combining nutritional education, physical activity 3 times per week and psychological supports.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Energy Expenditure between before and after weight loss | amount of energy expended during the walking tests, measured using indirect calorimetry | before and after the 12-week weight loss | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in lipid oxidation between before and after weight loss | amount of lipids oxidized during the walking tests, measured using indirect calorimetry | before and after the 12-week weight loss | 
| change in Fat mass between before and after weight loss | The amount of body fat will be assessed by dual energy X-ray absorptiometry | before and after the 12-week weight loss | 
| change physical activity preferences between before and after weight loss | Children will be asked to indicate their prefered physical activties and sedenatry behaviors on a computer task using visual analog scale (from 0 to 150 mm) | before and after the 12-week weight loss intervention | 
| Change in Energy Expenditure between the unloaded and loaded walking test | amount of energy expended during the walking tests, measured using indirect calorimetry | after the 12_week weight loss | 
| Change in lipid oxidation between the unloaded and loaded walking test | amount of lipids oxidized during the walking tests, measured using indirect calorimetry | after the 12_week weight loss | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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energy expenditure, weight loss, obesity, adolescents