When aerobics became choreographed and complicated, a generation of men dropped out.

And women never have been, in large numbers, fond of pumping iron.That's why Lonnie Burton of Body Masters fitness center was so interested in the 7-year-old New Zealand craze, "Body Pump," which is winning fans all over the United States. The trademarked cardiovascular exercise program combines weight lifting with aerobics to create a "high-rep" cardio class that gives "real results real fast."

The concept seems to be equally popular with men and with women.

The 60-minute class is carefully choreographed to work every muscle group using barbells and weights to the rhythm of motivating music, she said.

Les Mills Aerobics International, designer of The STEP, created the program. And to maintain program integrity, it won't let anyone use the "Body Pump" name unless he or she has become certified in an intensive two-day training program, which is followed by four to six weeks of choreography and technique practice.

Technique's important because, without proper body alignment, the desired results aren't there and injuries can result.

Instructors even have to pass a performance assessment before they can teach the class.

At this point, Body Masters at 8679 S. 2000 East is the only center on the Wasatch Front with certified Body Pump train-ing, although other clubs offer their own versions of the concept, Burton said.

One of the most appealing things about this type of cardiovascular workout, Burton said, is that people of all fitness levels can be in the same class and get great results. It doesn't get trickier as you get more advanced. What changes is the weights on the barbells.

Body Pumpers start out with a three-pound, specially designed weight bar, devoid of weights. Those are added incrementally as proficiency in the program improves.

A session begins with a general warm-up as pumpers are lead through a series of weight-bearing exercises, including squats, presses, lifts and curls, Burton said.

Because correct lifting techniques are crucial, both to getting results and avoiding injuries, each move has been choreographed by a physiologist and choreographer. That doesn't mean anyone dances. "There's no dance choreography and no one has to keep a beat," said Burton.

It does mean that anyone who attends a Body Pump class anywhere in the world should feel quite at home with it. The program - clear down to the order of the moves - doesn't change from place to place.

Burton said she laughed when she first heard about the program. It sounded like a fad. "I'm naturally skeptical. I didn't think spinning sounded like a great idea until I checked it out, either."

Spinning classes have been very popular at Body Masters, she added.

There's just one warning with Body Pump. Burton said it will, inevitably, change the shape of the participant's body.