The boys are not able to keep up with their friends in physical activities at kindergarten or school and they are often regarded as clumsy or lazy. Some parents notice that their son has large calf muscles. Pseudohypertrophy is a sign of muscle disease rather than a indication of good strength. There are some boys with Duchenne muscular dystrophy who have problems with delay in mental or language development. As a result the physical movement problems may be relatively less obvious in the early stages.
Some families seek medical advice because they recognise that their child has a problem.
For others the problem has only come to light as a result of a school medical examination or because teachers noticed that the child does not run or perform physical activities as well as most of the other children in his class. Other boys may have been sent for medical assessment because of delay in development, late walking or poor language development. On the surface, many of the early problems may seem to be far removed from a serious muscle disease. This is not too surprising as the signs of muscular dystrophy can be exceedingly difficult to detect in the early stages and many other conditions can produce similar symptoms. If the CK blood test result is very high, a muscle problem is likely to be present.