In retrospect , Almost all parents have noted that their child never walked or ran normally . Over the first few years of life these children have difficulty climbing and getting up from the floor. Parents often comment that their child falls frequently . Walking up on the toes is common . 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 .
This enlargement is due mainly to an increase in fatty tissue in the muscle . This enlargement 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. Early symptoms usually begin between the ages of 2 to 5 years. Muscle wasting is initially limited to the shoulder and pelvic areas.