Renee Olsen was already late when she arrived at the Soccerdome in Jessup, Maryland, with her two young boys. The soccer game was under way, and she was still strapping on shinguards, pulling up socks and tying shoelaces.

The difference? They were her shinguards, socks and soccer shoes. Olsen's boys were there to cheer on their 33-year-old mother. She's a real soccer mom.

Likewise, Sandy Ranck has three soccer-playing sons, but she's the one on the field Friday nights for the Shooters.

"Not to be confused with Hooters," says April Walker, 49, team captain and godmother to a moms-only soccer league that has 32 teams and more than 350 players.

"It's a huge stress reliever," said Olsen of Severn, whose 4-year-old and 2-year-old sons call to her from the sidelines. They're not cheering; they want her to get them drinks and a snack.

"Between work and the kids ..." said Olsen, who works in marketing and finance. "You feel like you got a workout, and you have a social network."

But Olsen and her teammates might be getting more out of their Friday soccer games than an hour of fun.

A study out of Denmark reports that playing soccer improves the health of women, especially in the areas of balance and muscle strength, and that was true even for women who never played in high school or college.

The researchers reported in the Scandinavian Journal of Medicine and Science in Sports that among 70 women ages 20 to 47 recruited for the study, the group that was assigned to play soccer showed increased bone density.

Dr. Sameer Dixit, an assistant professor of orthopedics and medicine at the Johns Hopkins University School of Medicine and a sports medicine expert, said the study was promising, but the subjects would need to be followed to determine whether the benefits were long-term. Dixit was particularly interested in the study's findings about bone health and muscle balance.

The women who played soccer in the study, as opposed to the women who just ran, appeared not only to have stopped bone loss but to have reversed it by three to six years.

But on this night, it is the Shooters who have suffered a reversal of fortune, losing 4-1. They play in the top division of the Soccer Moms league and most played in high school or college.

That's not the case with all of Walker's players; and the referees for the games played in the lowest division, made up of newcomers to the sport, teach rules and technique during games.

"We reserve the right to tell you you are too good for us," said Walker, who sends the best players to play on co-ed teams or in a highly competitive women's league.

Adult soccer appears to be booming among both men and women. Walker runs women's leagues at the Soccerdome in Jessup and Soccerdome II in Harmans. Jose Benitez, who owns both domes, says he has 80 men's teams and 60 co-ed teams just at the Jessup facility.

Games are played year round from 7 p.m. to midnight most days and draw players from as far away as Springfield and Arlington, Va.

"Soccer players are crazy," he said. "They will drive an hour for a game.

"I wish I could add a day to the week," said Brandon Quaranta, who manages the Du Burns Arena in Baltimore, where 50 to 60 teams play four or five nights a week.

"The number of teams have doubled in the last two years," he said. "And we are having to turn down teams every season. Players and teams are coming out of the woodwork."