my friends and I play racquetball alot. It's not the same as tennis obviously but I feel like I'm getting a pretty good workout when I play it nevertheless. I don't really like swimming that much though.

What are the intervals of working out when you just start on the treadmill? I read it in another thread a long time ago, but there are so many workout threads (lots started by me, sigh) and I forgot what it was.
Something like 1 minute run, 1 minute walk, 1 minute run, 1 minute walk, etc. etc. but it wasn't 1 minute to 1 minute ratio, it was something different, and supposedly that is the best thing to do on the treadmill/elliptical machine.