They're nobody's halftime show, the girls of Cheer Thunder.

On a hot summer night in a cavernous Gambrills gymnasium, two dozen teenage girls pound through a workout of precision handsprings, splits, cartwheels. One's wearing a leg brace. Another is taping her injured wrists for support. School's out for the summer, but they drill on and on, three days a week, two hours a day.

"1, 2 . . ." They clap, in unison.

"3, 4 . . ." Pounce forward on their toes.

"5, 6 . . ." Vault into the air, legs splayed, toes tapping outstretched hands.

"7, 8 . . ." Land -- hard. One stops to massage her aching hamstrings.

"C'mon, gotta smile!" shouts their coach. And they do, as cheerleaders always have.

Yet when football season comes around this fall, the girls of Cheer Thunder won't be smiling on the sidelines. They'll be in pursuit of their own championship season, taking their high-powered blend of dance and gymnastics to competitions as far away as Texas and Florida.

In the expanding world of women's athletics, girls today have more options than ever before, more role models in more formerly boys-only sports, like the U.S. women's soccer team and the WNBA.

Many still opt for cheerleading, but they're elevating it from its century-old role as moral support for the athletic endeavors of males into a sport of its own. The growing number of private squads operate independently of any school or team, existing solely to fulfill the competitive urges of a newly liberated generation of girls.

The squads don't cheer for anyone -- except themselves.

So when members of Cheer Thunder raise their voices -- HEY! Get rea-dy! Pre-pare fo-o-o-o-r-r-r the BEST! -- it's no secret who they're talking about.

"It's kind of a statement," Chrissy Czarnecki, 14, of Glen Burnie, says with a giggle. "We're trying to say that we are the best."

Many things are different within the aggressive new world of private cheerleading clubs, a circuit known as "all-star cheerleading," with at least 800 active squads across the country.

Cheering itself, in the literal sense, is optional. At least one national cheering competition no longer considers the old-fashioned rah-rah stuff. Most teams simply perform to recorded music.

Pleated skirts are out. They just don't flatter an athletic body. The new streamlined skirts that go with the competition uniform have a bit of a flip to them, but not much.

As for pompoms, no one at Cheer Thunder has anything against them in principle. It's just that if you were tumbling across the floor full speed and a pompom landed underfoot, you could really mess yourself up. So no more.

Then there are the cheerleaders themselves.

At 15, Brandi Moured, of Pasadena, is the picture of the consummate '90s teenage jock-girl, in gym shorts and a plain white athletic tank over toned triceps and a sports bra.

Her fingernails are painted blue, but her dirty-blond hair is scraped back in a ponytail, and she can do five back handsprings in a row -- a la Dominique Dawes -- if she has enough floor space.

She has the steely sense of purpose common to the women's soccer field, but she's been cheering since middle school. Just never for her school.

"I can't get what I want out of high school cheering," she says.

It used to be that high school cheering was among few outlets for athletic young women, who clamored to join the pennant-waving, pep-raising ladies' auxiliaries to the football or basketball teams.

But the rise of feminism brought the 1972 passage of Title IX, the federal law that forced schools to pour money into their women's athletic programs for the sake of gender equity, and a new generation of girls saw the doors thrown open to basketball, volleyball, lacrosse, softball, crew.

Cheerleading might have vanished. Instead, it harnessed the spirit of the times, evolving into a melange of highflying acrobatics and show-biz flair that required more athleticism than before.

"It used to just be standing on the sidelines," said Gwen Holtsclaw, president of Cheer LTD, a cheerleading supplies marketer and organizer of national championships. "Coaches said, `I better give them something more to go for, or they're going to play volleyball or soccer.' "

But while women's sports programs thrived in schools across the country, those involved in the newly pumped-up model of cheerleading chafed under high school restrictions.

Out of safety concerns, some school systems, including those in Ohio and Nebraska, banned the use of gymnastic stunts in cheerleading routines, limiting a team's ability to dazzle on the competitive level -- and inspiring some coaches and cheerleaders to go freelance.

Tina Edmondson, a former cheerleader and coach for Old Mill High School, formed Cheer Thunder in 1996 after Anne Arundel County -- like Prince George's County and many other school systems -- decided to designate cheerleading a sport.

That well-intentioned move, Edmondson said, was bad for high school cheering. Although the squads got more funds, they were bound by the same 300-mile travel restrictions as other sports teams. Which meant no more trips to the distant competitions where her cheerleaders could catch the eye of college recruiters -- and perhaps snare scholarships to perform with the more traditional, high-caliber squads that support football and basketball teams at the university level.

"There are tons of excellent cheerleaders in this county," says Edmondson, who also coaches a junior squad of two dozen preteen girls. "But if those kids could not travel, we couldn't get them scholarships."

That's the goal for many of her girls, and their parents, some of whom drive an hour or more from as far away as Frederick, Md., and Solomons Island. The parents pay gym fees of $42 a month for the Cheer Thunder workout and sell candy bars and raffle tickets to cover the competition costs. (The coaches are volunteers, though Edmondson charges for her optional cheerleading clinics.)

"Baltimore County doesn't allow a lot of gymnastics," Kathy Tirocchi says. But that's what the college scouts are looking for, she says, explaining why she drove her 15-year-old daughter, Jamie, all the way from Towson, Md., to check out Cheer Thunder. Jamie joined.

The mothers who wait outside the gym are small-haired, down-to-earth types -- soccer moms, sort of, except that they're not. Most were never cheerleaders themselves. They played sports and believe that what their daughters are doing is comparable. They dream of the day when cheerleading is elevated to an Olympic sport -- a distant, but not impossible goal, according to competition organizers.

Fewer than half of the Cheer Thunder girls serve on the cheerleading squads for their high schools. "High school [cheerleading] is like gossiping and typical girl stuff," says Jiselle Burkhalter, 17, a Pasadena resident who is the team's most rapid-fire tumbler. "Some people do it just to fit in, to be with their friends."

Most high school cheerleaders wouldn't make it in the pressure-cooker of all-star cheering, asserts Jen Provin, 17, who also cheers at Urbana High School in Frederick. "If they do join, they quit, because they're overwhelmed."

Overwhelmed, that is, by Edmondson's cardio-thumping regimen of relay races and kickboxing. Not to mention her prerequisites: Every girl must be able to do a back handspring. Most of them can do several in a row; half of them can do a clean, no-hands back flip.

"When I was in high school, I would have loved to have had this," muses Edmondson, watching Provin emerge dizzily from a series of somersaults. "I could have gone to a bigger college if I had had this level of intensity."

Some cheerleaders and their mothers whisper that local high school cheering squads are hurting these days, their talent drained by the growing number of all-star teams. The elders of cheerleading officialdom firmly deny it.

"It's just a different way to get involved," says Julie Davis, editorial director of the bimonthly American Cheerleader magazine. "The responsibilities of a school cheerleader are very different -- organizing special events and raising school spirit. It's great that there are different choices you can make."

For the girls of Cheer Thunder, the choice is clear: the empowering thrill that comes from being the main event and not just the sideline show anymore.

"It's more of a rush when you're out there competing for youself," says Ashley Hesgard, 17, of Gambrills. "You're not just cheering for a bunch of ugly boys."

CAPTION: From left, Michelle Death, Ashley Benway and Tina Cicala perform a stunt during a Cheer Thunder practice in Gambrills. The aggressively athletic private team gives teenagers an alternative to high school cheerleading.

CAPTION: (Photo ran in an earlier edition) A member of the Cheer Thunder squad prepares for practice in a Gambrills gymnasium. The private "all-star cheerleading" teams incorporate athleticism and acrobatics into their routines and compete across the country.