Effects of a 12-week Strength Training Program in Women With Myotonic Dystrophy Type 1

20 women with myotonic dystrophy type 1 (DM1) will complete a 12-week lower-limb strength training program. The training program consist of 3 series of 6 to 8 maximal repetitions of 5 different exercises: Leg extension, leg press, hip abduction, squat and plantar flexion. Training sessions will be closely supervise and take place twice a week. It is hypothesize that the training program will induce muscular hypertrophy despite the genetic defect. The training program should also have positive effects on function. The participants will be evaluated at baseline, week 6, week 12, month 6 and month 9 to quantify the effects of the training program and if these effects will be maintained over time.

Participants will complete a 12-week strength training program and return to their normal activities for the following 6 months after the end of the training program.

Most outcomes will not be mask, however the outcome assessor will be mask for all muscle biopsy analysis: while analysing the muscle biopsy outcomes, the outcome assessor will not know if it was from baseline or from after the training program.

12-week strength training program of the lower limbs consisting of 5 different exercises: Leg extension, leg press, hip abduction, squat and plantar flexion. All exercises will be perform between 6 and 8 maximal repetitions.

12-week strength training program of the lower limbs consisting of 5 different exercises: Leg extension, leg press, hip abduction, squat and plantar flexion. All exercises will be perform between 6 and 8 maximal repetitions.

Changes in maximal isometric muscle strength of the knee extensors measure by quantify muscle testing using a handheld dynamometer

Changes in maximal isometric muscle strength of the knee flexors measure by quantify muscle testing using a handheld dynamometer

Changes in maximal isometric muscle strength of the hip flexors measure by quantify muscle testing using a handheld dynamometer

Changes in maximal isometric muscle strength of the hip extensors measure by quantify muscle testing using a handheld dynamometer

Changes in maximal isometric muscle strength of the hip abductors measure by quantify muscle testing using a handheld dynamometer

Changes in maximal isometric muscle strength of the ankle dorsiflexors measure by quantify muscle testing using a handheld dynamometer

Changes in maximal isometric muscle strength of prehension measure by quantify muscle testing using a hand grip dynamometer

Changes in the score of the lower extremity functional scale (LEFS). The LEFS is an 80-point questionnaire with 20 items scored from 0 to 4. A score of 80 means no disfunction while a score of 0 means maximal disfunction.

Changes in the score of the myotonic dystrophy health index (MDHI). The MDHI is a 114-item questionnaire scored from 0 to 100, where 0 means no disability and 100 means maximal disability.

Changes in the score of the Fatigue and Daytime Sleepiness Scale (FDSS). The FDSS is a 12-item questionnaire where all questions are scored from 0 to 2. A higher score means more daytime sleepiness and fatigue.

Changes in the Marin apathy scale. The Marin apathy scale is scored by the clinician where he interviews the subject and then scores an 18-item list on a scale of 1 to 4. A high score means more apathy.

Changes in the Hospital Anxiety and Depression Scale (HADS). The HADS is a 14-item questionnaire with a scale from 0 to 3 for each item. A high score means high depression and anxiety.

Changes in muscle biopsy of the vastus lateralis: mitochondrial function. Analysis of mitochondrial markers and enzymes

Changes in muscle biopsy of the vastus lateralis: Nuclear foci (changes in accumulation of nuclear foci)

Change in the score of the Brief Pain Inventory. The Brief Pain Inventory is a self-administer test that asses the dimensions of pain such as intensity of pain, functional incapacities, social and family repercussions, and psychological distress.

Change in score of the DM1-Activ questionnaire. This questionnaire asses activity and social participation with DM1 population. It contains 20 items with a maximal socre of 40 points, a lower score represent a bigger impact of the disease on activities and social participation.

Change of the center of pressure (COP) measure in static posturography : closed eyes bipodal position

Change of the center of pressure (COP) measure in static posturography : open eyes semi-tandem position

Inclusion Criteria: DM1 diagnosis must be confirmed by genetic analysis; Women sex, aged between 30 and 65 years old; Be able to walk without assistance; Consent of the neurologist must be given to participate in this study; Must reside in the Saguenay-Lac-St-Jean region; Subjects must be able to give their consent freely and voluntarily. Exclusion Criteria: Patients with any other form of muscular dystrophy are excluded; Any contraindication for strenuous exercise or muscle biopsy.