About a month ago I started using the elliptical trainer at my gym for about 20-25 minutes a day two or three times a week. I've noticed a really significant improvement in my tennis footwork since then! Part of it may be the leg strengthening I'm getting out of it, but I think part of it is also the balance. If you've used an elliptical trainer before, you'll know that it takes a while to learn to get your balance on it. I'm thinking that other balance-improvement activities out there might improve my footwork even more. Any suggestions? Jumping rope perhaps?