Functional ability and muscle force in healthy children and ambulant Duchenne muscular dystrophy patients

In ambulant patients with DMD, we found that muscle function assessed by timed functional tests (running 9 m and rising up from the floor) and muscle force assessed by hand-held dynamometry were severely impaired. However, a small reduction of muscle force was accompanied by a large reduction in functional ability. Therefore, in our group of ambulant patients with DMD, timed functional testing was the most sensitive parameter to determine the extent of disease progression. Timed functional testing may therefore be considered as an additional outcome measure in drug trials to evaluate the effects of therapy in ambulant patients with DMD and possibly in other neuromuscular disorders.