Myasthenia gravis (MG) is a rare autoimmune disease with dysfunction of the postsynaptic transmission at the motor endplate. The early fatigue of muscle strength that varies depending on the time of day is a typical sign of MG. It is unclear, if intensive muscle training can induce early fatigue of muscle strength and lead to an exacerbation of myasthenic symptoms. In the literature, five studies were found with adult patients diagnosed with MG: one randomized controlled study, three open studies and one case report. The data of these studies are listed in tabular form in the book's chapter. All studies had a short running time of 5–12 weeks with continuation of the pharmocological standard therapy with cholinesterase inhibitors, prednisolone and/or immunsuppressive agents. The effect of muscle training on muscle strength was analyzed in one study and the case report; three studies examined in first line the effect of respiratory muscle training on respiratory function in patients with MG. Only the randomized controlled study included investigations to evaluate quality of life. There was not any worsening of myasthenic symptoms in any study including respiratory functions, even in the group with clinically more pronounced MG. Relevant training-associated side effects did not occur. The inspiratory muscle strength improved in 2/2 studies, the endurance of inspiratory muscle strength in 2/3 studies under regular respiratory muscle training. Follow-up screenings were done in one study after 3–5 months. At that point the achieved amelioration of respiratory muscle strength endurance had decreased by 25 %. Larger and longer studies with follow-up screenings are necessary to validate the so far documented positive effects of muscle and respiratory muscle training and to define the optimal type of training and function tests.