Find the nearest, most convenient cement slab in your backyard. Place a basketball pole and goal at one end, a table in the middle, and a basketball at the other end. Pick up the basketball and take a shot. When you miss, practice following your shot (with your body, not just with your eyes). The table in the middle serves as an obstacle, much like other people do when you are actually playing ball.
Unless you’re looking to throw a little cash towards a cash strapped orthopedist you know, read no further. Or better yet, just write the guy (or gal) a check.
Medical training or not, we are all familiar with the intended use of certain joints. The ankle, for example, is no more intended for lateral movement than the side of your foot is made for bearing weight. With this in mind, imagine that the side of your foot was unexpectedly called on to not only bear your weight, but to halt its acceleration (at a rate of 9.8 meters per second-squared)? Now imagine that in addition to bearing your weight and ceasing your body’s downward acceleration (at a rate of 9.8 meters per second-squared), the rest of your leg was engaged in the process of applying sufficient force to launch your body back into the air. Try and try as you might, you won’t find this one in the owner’s manual.
Why would an ankle find itself in this situation in the first place? Take yourself back to the cement slab and table. Picture yourself running around the table. You see that the ball is about to come your way, having bounced off of the rim like a red brick bouncing off of a light post. In one graceful movement you attempt a running stop off of one foot, intending to re-launch yourself into the air towards the ball, but your foot unexpectedly finds the leading edge of the cement slab. Unfortunately for your ankle, foot and lower leg, the edge of the slab finds the wrong side of a pivot point, and your foot rolls over the edge. Now picture your ankle swelling to three times its normal size. Imagine finding bruising on your foot, leg and toes. Not merely mortal bruising, mind you; but angry, purple bruising.
I sit here at work, my foot elevated, awaiting x-ray results.