Maureen Childs can really make Alexandria's city manager, its deputy sheriffs and a city judge jump.

Well, at least for 45 minutes she can.

Twice a week, while most Alexandrians are stretching and sipping their morning coffee, Childs leads a group of city employes through the stretches, bends, jumps and jogs of an aerobics workout to the strains of moldy oldies such as "Build Me Up Buttercup" and "Wake Up Little Susie."

Dressed for fitness success in T-shirts and sweatpants of assorted colors and varying degrees of disintegration, her class gathers at 7 a.m. in the gymnasium at Lee Center on Rte. 1. They demonstrate how the fitness trend, which has scores of federal employes jogging across Memorial Bridge at lunchtime every day, has also reached government on the other side of the Potomac.

City Manager Doug Harman, sweating and puffing, is a stalwart of the group. An amateur cartoonist, Harman sports a T-shirt with a large drawing of Mickey Mouse: "a symbol of government," he said.

General District Court Chief Judge Daniel F. O'Flaherty, 59, said, "I'm the old man of the crowd. I might make mistakes, but I keep moving with the rest of them."

He says that since he started this routine he feels better and has lost 35 pounds, bringing his weight down to 185 from 220.

"For enthusiasm, stick-to-itiveness and dedication, certainly the judge is at the top of the list," said Dottie St. John, 31, assistant training officer in the city fire department and one of the three women who regularly attend the Tuesday and Thursday sessions.

"The judge puts us to shame," said Deputy Sheriff David Rocco, 26.

The aerobics class was started in order to give personnel in the sheriff's department a group activity that would fulfill an on-duty, two-hour-a-week physical exercise requirement. The fitness obligation is aimed at reducing sick leaves and disability retirements as well as improving job performance, according to Capt. Robert O'Bannon.

City firefighters have a similar workout requirement. But, so far, St. John is the only city fire department employe to join the aerobics class.

Despite the early hour, most of the group of about 30, largely made up of deputy sheriffs, are enthusiastic.

Those who aren't get the Childs' "dirty look," she said, and sometimes a Childs chide.

"What kind of exercise is that?" she asked Deputy Sheriff Michael Kimble, 33, who was lying on the floor and straining to get his knee all the way up to his elbow.

Childs, a graduate student in exercise physiology at George Washington University and aerobics instructor at an Alexandria health club, was hired in April to conduct the aerobics class. O'Bannon led the program for a few months before Childs took over.

There were "mixed feelings" about her when she began because "I was someone coming in from the outside and making them do something that was traditionally for a woman," said Childs, 27.

But those feelings subsided as the participants found they felt better, she said. "It took a while, a lot lost weight and all of their pulses have gone down. We have a good time."