Maybe you’ve seen your friend put her leg behind her neck. Or the friend who can bend his fingers in ways that look totally unnatural. The term double-jointed is frequently used, but it isn’t accurate. You will never hear of a person exiting Paragon Orthopedic Center with that diagnosis. Hypermobility is the correct way of describing these abilities to have excessive joint motion. People with joint hypermobility don’t have twice the amount of joints, nor do they have twice the normal motion. About 10-20% of the healthy adult population have hypermobile joints. Some people can train themselves to have increased joint mobility for certain activities, such as gymnastics. Unfortunately for those of us who are older, this ability gets harder to do the older we get, which is why you don’t see many 80-year olds doing the splits.