I'm jogging on the treadmill when I hear a loud bang behind me. Without turning around I have a pretty good sense that the sound is part of someone's workout. It's the sound of a large medicine ball being forcefully thrown down to the ground. But still, I can't resist turning my head for a moment to look.
Sure enough, as I turn to see a woman and her trainer throwing the medicine ball, I begin to lose by balance on the treadmill. Luckily, I caught myself fast enough and didn't fall.