Forget rules -- this tennis workout is quick and dirty

If this wasn't the genteel game I was used to, that's exactly the point. Called cardio tennis and officially launched at the recent U.S. Open, it's being touted as a high-energy workout that burns more calories than singles or doubles by elevating the heart rate into the aerobic training zone for most of an hourlong class.

Usually limited to four to six people, it starts with a 10-minute warm-up followed by 45 minutes of cardiovascular conditioning -- including team games and forehand, backhand and volley drills -- ending with a five-minute cool-down.

Created to get players into better shape and draw new ones to the sport, it's the brainchild of the United States Tennis Assn. and the Tennis Industry Assn., a trade group that has seen participation decline or remain flat in recent years.

To reverse that trend, cardio tennis is being billed as "a third way to play" and a quick and dirty workout that's both fun and fat-burning. That's where that aerobic music comes in, in an effort to inspire movement and funk-ify the sport's fuddy-duddy image.

The workout is being offered at 760 public and private courts across the country, including 70 locations in Southern California, which is how I found myself on a homeowners association court on Beverly Glen Boulevard, the nearest class I could find on the Westside (though one in Mandeville Canyon is scheduled to start up soon).

Like any good tennis player, the first thing I did on arriving was size up the other class members and their ability to clobber me.

Who was the lefty who would be my own personal Rafael Nadal? Who had Lindsay Davenport's serve? Who had Lleyton Hewitt's wheels? There were four other women, in their 30s and 40s, and with varying degrees of experience: Tina, who's been playing since high school; Kathy, who learned the game six months ago; Jennifer, who hadn't picked up a racket in 10 years and just had a baby; and Azadeh.