In general, patients should try to avoid getting the cast wet or water inside cast. Infections can result from getting cast wet and the cast may then have to be replaced early. Of course check with your doctor before doing any water or sports activities while in a cast.

In theory, the cast prevents movement of the bones and is specifically designed to allow one to perform activities without worrying about the bones shifting and healing incorrectly. In practice, no cast is 100% perfect and any strenuous activity will increase the risk of fractured bones shifting, thereby causing delayed healing or incorrect healing. I hope this helps.