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

Eleven men with myotonic dystrophy type 1 (DM1) underwent a 12-week lower-limb strength training program. The training program consisted 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 were closely supervised and took place twice a week. It is hypothesised that the training program will induce muscular hypertrophy despite the genetic defect. The training program should also have positive effects on function. The participants were evaluated at baseline, week 6, week 12, month 6 and month 9 to see the effects of the training program and if these effects are maintained over time.

Participants had to 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 where not masked, however the outcome assessor was masked for all muscle biopsy analysis: while analysing the muscle biopsy outcomes, the outcome assessor did 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 were performed between 6 and 8 maximal repetitions.

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

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

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

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

Changes in maximal isometric muscle strength of the ankle dorsiflexors measured by quantified muscle testing using a handheld 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 Well-Being Manifestations Measure Scale (WBMMS). The WBMMS is a 25-item questionnaire where each question is scored on a scale from 1 to 5. A high score means high well-being.

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)

Inclusion Criteria: DM1 diagnosis must be confirmed by genetic analysis; Male gender, 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.