The purpose of this study is to demonstrate that a 3 months physical exercise programme improves the Quality of Life of patients with generalized Myasthenia Gravis (MG) stabilized since at least 6 months under prednisone and/or azathioprine.

Three centers randomized simple blind clinical trial whose objective is to assess the efficacy on QoL improvement, and the tolerance of physical exercise over a period of 3 months in patients with generalized MG who have been stabilized since at least 6 months.

During the 3 months pre-inclusion phase, the characteristics of MG will be collected. Physical activity and performance will be assessed monthly.

MGQOL15 will be assessed at inclusion.

Patients will be randomized in either intervention arm or control arm.

The intervention arm will consist of three sessions exercise per week during three months. The daily exercise will be performed on a rowing machine that will be adapted to the patient's own physical ability.

Physical activity will be measured with the help of an actimeter.

Once a month, MG evolution and tolerance to exercise will be assessed and MG treatment dose will be collected.

Exercise will be interrupted in case of MG exacerbation.

Quality of life and psychological status will be assessed at 3, 6 and 9 months.

Plasma levels of pro and anti-inflammatory cytokines will be measured at 3, 6 and 9 months in order to assess the effects of exercise on immune response.

Patients enrolled in the control arm will benefit from the same follow-up but will not have exercise.

Inclusion Criteria:

1. Patient with generalized MG of stage II or III according to the MGFA classification, stabilized for at least 6 months. Criteria for MG are either

   • positive dosage of ant-RACh or MuSK auto-antibodies;
   • If absent, myasthenic symptoms decrement> 10% in EMNG and test the positive prostigmine

2. Patient ≥ 18 and ≤ 70 years old

3. Patient having an health insurance

4. Informed written consent

Exclusion Criteria:

1. Patients under particular protection

2. Enrolment in another biomedical research in the last 3 months;

3. Patients for whom physical practice is contra-indicated because of :

   • Unstable coronary Syndrome or myocardial infarction within the past 3 months
   • Heart failure with systolic ejection fraction < 50 %
   • Respiratory failure defined by a vital capacity (CV) < 70 %
   • Stroke
   • Other neuromuscular pathology
   • Disabling Rheumatologic disease (> 80 % disability according to the Barthel scale)
   • Chronic Pain or disabling orthopaedic conditions
   • Hospitalization in the last 3 months for a serious medical or surgical condition
   • Anemia (hematocrit < 30%)

4. MGFA grade I, grade IV or V

5. Severe cognitive impairment

6. MGQOL-15 below 15/60