Why do children with Duchenne muscular dystrophy have difficulty climbing stairs?

Children with Duchenne muscular dystrophy experience difficulty climbing stairs due to the progressive weakness and degeneration of their skeletal muscles.1

This condition is caused by a genetic defect that prevents the body from producing a functional protein called [dystrophin]. The absence of dystrophin disrupts the membrane covering muscle fibers, leading to the entry of excess calcium ions into the cells and subsequent cell degeneration. As the disease progresses, muscle fibers are replaced by fibrous scar tissue and fat, which results in a significant loss of muscle strength and function.21

Because the disease often involves the muscles of the limb girdles—specifically the pelvic muscles—children struggle with movements that require significant lower-body strength, such as climbing stairs, rising from a sitting or lying position, and raising their knees. Over time, this muscle wasting progresses upward, eventually affecting the arms and the diaphragm.21