People suffering from muscular dystrophy should avoid over exercising, say experts.
Pain or a heavy feeling in the arms or legs after exercise can be caused due to training of body muscles, according to the Germany Professional Association of Neurologists.
Muscular dystrophy is a genetic disease that causes progressive muscle weakness and over 30 forms of the condition have been identified.
"If weakness appears within 30 minutes of exercise or muscle pain between 24 and 28 hours after training, then they are warning signals that indicate strain," explains Curt Beil from the association.
Further indicators are severe muscle cramps, prolonged shortness of breath and heavy body-extremities.
Beil advises sufferers to avoid strenuous activity because, in the case of a rapid development of the condition, it can lead to faster degeneration of the muscles.
But he recommends mild exercises like walking, swimming or cycling as they can improve stamina and reduce muscle weakness.
"In essence, the goal of exercise should be to improve the muscles' function rather than make them stronger," says Beil.
Muscular dystrophy leads to under-production of the protein dystrophin. This in turn eventually results in the degeneration of muscle tissue and interferes with the transmission of nerve signals to the muscles.