 Duchenne muscular dystrophy DMD is the most common lethal inherited disorder worldwide. Despite the exponential increase in our understanding of the disorder since the discovery and characterization of the causative gene and its product dystrophin in 1987, current therapeutic management remains largely supportive. Awaiting a final genetic cure to be available in the future, further investments in developing better drug therapies for DMD remain important. The effect of a high dose prednisone regimen will be evaluated in comparison to a daily dose regimen in a multi-center, randomized, double-blind placebo-controlled 4-arm study. Ambulant children aged 4-10 years with an established DMD diagnosis will be studied. Patients will undergo 2 screening evaluations within 1 week. Patients will be randomized into treatment groups on the second screening visit, followed by a 12-month treatment period. During the treatment period, patients will be evaluated at monthly intervals. The primary endpoints are percentage change in average muscle strength score and QMT performance for specific muscle groups. Secondary endpoints include timed function tests, functional grades for arms and legs, and pulmonary function tests. 