I get my drive and determination from just winning and playing tennis. I know if I don't work, I won't get rewarded. It was a life long dream to win a Grand Slam so when I was able to do that it felt so good and I wanted to do it again. It's not that hard to stay motivated.

I think Serena Williams is the best tennis player of this generation, if not the best ever. It is amazing for her to be playing as well as she is at the age of 31.

Tennis takes care of everything. It requires agility and quickness to get to the ball, core strength to get power into your shorts and stamina to last for an entire match. In addition to toning your arms and shoulders, it's a total body workout for your legs and abs, and works your heart and core unlike any other sport.

I get my drive and determination from just winning and playing tennis. I know if I don't work, I won't get rewarded. It was a life long dream to win a Grand Slam so when I was able to do that it felt so good and I wanted to do it again. It's not that hard to stay motivated.

In tennis it's easy to get greedy - and one Grand Slam doesn't feel enough any more.

I started mountain-bike riding two years ago, which is much better than riding a stationary bike in the gym. Mountain biking is a total body workout.

I think I will always stay involved in tennis and would like to give back by helping out young players. I have done a little commentary and may one day enjoy doing that again.