The massive size of offensive and defensive linemen is one example of inertia of inertia being used to advantage. But if you take these giant football player and put them in a sport like squash or badminton, their mass and inertia work against them. It's no good having tremendous mass when sudden and varied movement changes are required unless you have the strength to move your mass quickly and to control it once it's moving. Most massive athletes have a poorer strength to weight ratio than smaller, less massive athletes, so they have a harder time stopping, starting, and changing players are lean, lightweight, and anything but massive! If you're a small, lightweight squash player, you can get a lot of pleasure from making your massive opponent crash into the side walls! You have a friend helping you in the court— your opponent's inertia!