Outdoor playing fields might not be getting much use this month by local sports teams, given the cold temperatures, but the players are alive and running at large indoor facilities in the county that have enough room for soccer, lacrosse and similar games.

In a large facility called Sports Network in Manassas, several thousand sports enthusiasts pass through the revolving door each week. At Arena Sports in Woodbridge, athletes of all ages and abilities are crowding in to play soccer and deck hockey.

At both places, the teams rotate on and off the field all evening until after midnight on weekdays. The games start at 6 a.m. on weekends to meet the demand for playing time.

For most participants, appearances aren't important. They arrive minutes before game time, uniforms are often mismatched, rules are relaxed and many teams don't have coaches. They are here to play, hone their skills, keep in shape, socialize.

With the smell of sweat lingering in the cool air and screams echoing off the walls, these games are more for players than spectators. But fans at both facilities can watch games from a single row of seats overlooking the field, and the adjacent lounge serves snacks and drinks.

"We play here because you can't play outdoors. This gets you exercising on the weekend," said Dan Calvert, of Reston, a lacrosse player from South Lakes High School.

His teammate, Adam Casagrande, said that although some people compare the indoor game with the outdoor, "it's really very different."

"This {inside} game is a bit faster, a lot quicker, with more transition" from defense to offense, said Rob Dudley, of Montclair. It provides conditioning and "it's something to do on a Saturday that's not sitting around all day."

The games are faster because of the artificial turf, and because of the enclosed field, which prevents the ball from going out of bounds. There are slight rule differences to accommodate a smaller field, a shorter game and fewer players per team.

The athletes don't battle the weather as in other seasons. There are no puddles on the field, no games called on account of rain. Players don't leave clean, but their jerseys show no dirt. And rug burns are their battle wounds.

For players such as Nancy Costa, of Woodbridge, the soccer program at Arena Sports is a family affair. Nancy and her husband, Bob, each play one night a week with local teams. On the weekend, they play together on a coed team. Their son, Michael, plays in a youth league. And Nancy Costa, 43, plays a second weeknight in a league on a converted basketball court at the Dale City Recreation Center.

"The {lounge} area is a big draw here {at Arena Sports}. We can come here for a 7 o'clock game and not leave until 1 a.m. We close the place down," she said. "This is like our family in here during the week."

Costa likes the chance to learn the game in a league that considers the players' skill level. "People come in here who have never played in their lives. There are late bloomers, like me, who don't have the skill level {of more experienced players}. This gives you a chance to improve your skills," she said.

Because there are few large indoor facilities like Sports Network and Arena Sports in the Washington area (another one is in Gaithersburg), they serve players from across the area.

Three new facilities -- in Baileys Crossroads, Sterling and Springfield -- are being planned, said Bill Turnbull, a manager at Sports Network. Although those existing are very popular right now, business is lean in warm weather, and all may not survive the seasonal competition, he said.

Teams pay $400 to $500 each winter season. The cost, which is less in the warmer months, is usually divided among the players.

Sports Network was built in 1986. The soccer field is a standard indoor size with a 40-foot ceiling. The building is 200 feet long and more than 70 feet wide. Arena Sports, built three years ago, is about the same size, with part of its space devoted to a weight room and fitness area.

The facilities each are used by several thousand athletes playing for a few hundred teams, according to their staffs. The only problem is fitting in everyone who wants to play.