Progressive muscular dystrophy refers to a group of hereditary myopathies characterized by progressive weakness, deterioration and regeneration of muscle fibers. Duchenne muscular dystrophy (DMD)is an X-linked recessive disorder that affects 1:3500 males and is caused by mutation in the dystrophin gene which is responsible for the maintenance of mechanical stability at the muscle cell membrane. Symptoms are seldom noted until the child is between 2-5 years old. The disease affects male only and is inherited in the female line. The major characteristics of the disease are muscle wasting, weakness and concurrent hypertrophy. Usually between the age of 8 to 12, severe contractures and muscle weakness are apparant and most children are unable to ambulate. There has been a debate for many years on whether muscular training is beneficial or harmful for patients with myopathic disorders. So we have tried to evaluate the effect of a well-designed isokinetic rehabilitation program on patients with DMD and clarify whether muscle strength training exercises cause improvement or further deterioration in those patients.