Myotonic Dystrophy Type 1 and Resistance Exercise

Study Overview
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Brief Summary
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The purpose of this study is to investigate the response after one bout of moderate-heavy resistance exercise in patients suffering from Myotonic Dystrophy type 1. There is still doubt about if these patients could benefit from resistance exercise, or if this mode of exercise is detrimental to their mobility and health. We aim to monitor the subjects during the recovery phase and investigate recovery in several ways.

Detailed Description
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Myotonic dystrophy type 1 (DM1) is an autosomal, dominantly inherited, muscular disease and the most common muscular dystrophy amongst adults. The disease is characterized by progressive myopathy and myotonia, first evident in the distal parts of the body: calves and forearms, further progressing towards proximal parts. A recent review by Voet and co-workers (2013) concludes that exercise is safe for DM1-patients, and based on our current knowledge, DM1-patients should be able to gain positive adaptations from exercise. However, the physiological outcomes of an exercise stimulus are not well studied in this population and because of alterations in important Ca2+ handling systems the recovery processes might be significantly different from healthy muscles. The aim of this study is to investigate the acute responses to moderate-heavy resistance exercise in DM1-patients. We aim to establish a timeline for recovery of muscle strength, measured as maximal voluntary contraction. In line with this, we want to investigate if any muscular damage has occurred with both direct and indirect measures, and possible mechanisms leading to muscle damage, i.e. impaired Ca2+ handling.

Official Title
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Recovery After Moderate-Heavy Resistance Exercise in Myotonic Dystrophy Type 1-patients

Conditions
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Myotonic Dystrophy 1

Intervention / Treatment
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* Other: Moderate-Heavy Resistance Exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Confirmed Myotonic Dystrophy type 1-diagnosis Exclusion Criteria: Non-ambulatory Injuries to muscle-skeletal-system that prevents resistance exercise Severe affection of the cardiovascular system Cognitive affection Lives more than one hour from test site

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 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: Factorial Assignment
Interventional Model Description: Participants in both groups (patients and control) perform unilateral leg resistance exercise, contralateral leg serves as control
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: DM1-Ex<br>Moderate-heavy resistance exercise of one leg in DM1-patients | Other: Moderate-Heavy Resistance Exercise<br>* Leg press: 3 x 8 repetitions at 75% of 1 repetition maximum, 3 minutes rest between sets. Knee extension: 3 x 6 repetitions at 85% of 1 repetition maximum, 3 minutes rest between sets.<br>|
| No Intervention: DM1-Rest<br>Control leg (i.e. no exercise) in DM1-patients | |
| Experimental: Ctrl-Ex<br>Moderate-heavy resistance exercise of one leg in healthy participants | Other: Moderate-Heavy Resistance Exercise<br>* Leg press: 3 x 8 repetitions at 75% of 1 repetition maximum, 3 minutes rest between sets. Knee extension: 3 x 6 repetitions at 85% of 1 repetition maximum, 3 minutes rest between sets.<br>|
| No Intervention: Ctrl-Rest<br>Control leg (i.e. no exercise) in healthy participants | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in muscle strength | Recovery of knee extension torque | Baseline, and 5 minutes, 3 hours, 24 hours, 48 hours, and 71 hours after exercise | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle protein synthesis rate | Rate of muscle protein synthesis in m. vastus lateralis between baseline and 27 hours after final session of resistance exercise | Baseline and 27 hours after final session of resistance exercise | 
| Muscle protein breakdown rate | Rate of muscle protein breakdown in m. vastus lateralis between baseline and 27 hours after final session of resistance exercise | Baseline and 27 hours after final session of resistance exercise | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Resistance exercise, Recovery, Muscle protein synthesis, Muscle protein breakdown, Muscle function