Protein is important and hard for me to get in a hurry. We're busy. I don't always remember to thaw the chicken for dinner. I always have eggs, and they're light and satisfying. I never feel stuffed at the end of it.

I started swimming when I was four because my brother wanted to join a swim team, and I wanted to do what he did. They said I had to be six, but if I could swim a lap, then I could participate. So I swam a lap, and the rest is history.

Indoor pools just don't seem as inviting to me.

Tennis is interesting because the women are almost more popular than the men. In the U.S. Open, women even get exactly the same money as the men.

The kids know what I'm doing when I exercise, and that's powerful. So don't just tell your kids to go play outside. Take a moment off your computer, put on your tennis shoes, hop outside and help them start their game and run off some energy.

I grew up in northern California, where it was consistently in the hundreds in the summertime. My dad didn't think he should have to turn on the air conditioning when we had a swimming pool in our backyard; it was our built-in air conditioner.

Thinking about your training should put a smile on your face. As cliche as it sounds, you are worth all the time and energy you've put in. Unleash your emotions with a cheer, or even a signature roar, after a tough workout.