An exercise regimen (PRIME: Proximal Resistance In-House Movement Exercise) has been designed for patients with myotonic dystrophy type 2 (DM2). The hypothesis is that this patient-friendly physical therapist (PT)-guided exercise program associates with improved functional capacity and muscle composition in DM2 in this two-period two-sequence cross-over study. Thus, participant will be randomized to one of the three possible groups. Participants in GROUP A will perform exercise routine virtually under the direct supervision of a physical therapist once a week and another session on their own for the first three months, then they will continue with same exercise routine at home for the last 3 months on their own. Participants in GROUP B will perform exercise routine virtually under the direct supervision of a physical therapist twice a week for the first three months, then they will continue with same exercise routine at home for the last 3 months on their own. Participants in GROUP C will perform exercise routine on their own during the first 3 months, then they will perform exercise routine virtually under the direct supervision of a physical therapist. Each group will include around 8 participants. Duration of the study is 6 months. In addition to exercise sessions, participants will have evaluation of their strength, motor function and muscle composition at three time points: initiation, 3 months and completion of the study at 6 months. Muscle composition will be assessed by electrical impedance myography which is a portable, non-invasive, painless and non-radiation tool that applies a weak high multifrequency electrical current to the examined muscle and allows to obtain information about its composition.

Inclusion Criteria:

• Patients with genetically confirmed myotonic dystrophy 2 (DM2) who are ≥18 and ≤ 70 years old.
• Patients are ambulatory without need of any assistance or device.
• Patients have a normal ECG within the 3 months prior to Screening visit (of note, patients with DM2 are recommended to have routine ECG as part of patient care. So, this ECG will be done as part of patient care).
• Body mass index (BMI) ≥20 and ≤30.

Exclusion Criteria:

• Subjects younger than 18 years old or older than 70 years old.
• Inability or unwillingness of the subject to give written informed consent.
• Subjects with pacemaker.
• Blood pressure <90/50 mmHg or >160 mmHg/90 mmHg at Screening visit
• Resting heart rate of <60 or >100 beats/minute at Screening visit.
• Any fall within the last six months.
• Any history of syncopal episodes or family history of sudden death.
• Patients who are pregnant or plan to become pregnant. A urine pregnancy test will be performed at visit 1 and 3 for women of childbearing age. If positive or if subject is planning to become pregnant, subject will be not eligible for the study.