Cdr Chris Hadfield: Weightlessness is cool. It lets you do things you just can't do anywhere else. You can fly and float and turn. But it doesn't come for free. Without constant load on your body, you can get incredibly lazy. Your muscles will start dissolving. Your bones will start getting reabsorbed back into your body.
So to stay strong to go out on a space walk and fight the space suit, or so you're strong enough to walk around when you get home again, we have to exercise. We have to demand that our bodies stay strong. And we do that in various exercise equipment here on the Space Station, including T2, Treadmill Number 2, the Terminator, right here on Space Station. Time to exercise.
So... make sense? That's how we exercise in space, keeping ourselves strong and fit and ready for whatever might happen. Bye.