The human body is meant to be in motion. If you are off your feet too long it is sometimes hard to get back to your regular self. This can be especially true with the elderly.
Physiotherapy or physical therapy is a health profession dedicated to keeping people mobile, especially after injury.
After an injury it is necessary for a trained professional to explain the best way to exercise your body to help the injury, not add more stress to the situation.
Part of physical therapy is to be a kind of cheerleader as well. Some people need more encouragement to work their injured body back into shape. This can be even more important in the case of a nasty fall. After a fall people can fear the simple act of walking. Fear of another fall runs deep and a physical therapist needs to gently push a person to get on their feet again with firm support and praising any accomplishment.