Wii Tennis Workout (Score 1)

I've been playing the 1st Wii Tennis training mini-game to get a nice aerobic workout. It's simple enough to keep going without much frustration. What I do is take a step forward on the same foot as the arm I'm swinging with and when the character gets close to the net, I'll switch it up and side step in the direction of the swing. About half an hour of that I get a good workout.