• Quantitative muscle strength will be measured using the CINRG Quantitative Measurement System (CQMS) [ Time Frame: February 2008 ] [ Designated as safety issue: No ]
  
• Primary strength endpoints will be quantitative myometry (QMT) scores of the upper and lower extremities, consisting of paired flexor/extensor groups. [ Time Frame: February 2008 ] [ Designated as safety issue: No ]
  

• Secondary strength endpoints will include individual QMT scores of elbow and knee flexors and extensors and hand grip, manual muscle testing scores, which will be measured using the Medical Research Council's (MRC) muscle strength scoring method. [ Time Frame: February 2008 ] [ Designated as safety issue: No ]
  
• Side-effect profiles will assessed by monitoring side-effects, including differences in growth (height and weight), calculated weight/height ratio, bone density, cataract formation, blood glucose, blood pressure and behavioral changes. [ Time Frame: February 2008 ] [ Designated as safety issue: Yes ]
  

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.