Mobility – think of it as the active range of movement. It is the ability of a joint to move through its entire range of motion fluidly. Mobility is not just about the muscles, but the joints that allow for movement as well. A good way to vision mobility is like opening a door. The hinge should open and close smoothly and without resistance. Now imagine trying to open the door and it getting stuck half way. That’s a (simplified) way of looking at lack of mobility – and this is all too common for age group athletes.