The roar! After years of bad crowds and a worse press, back when they looked like an ice-staking team from the Vatican, the Redskinettes just listened and listened as it crashed down from the Kennedy Stadium stands on Sunday, the great beery id-bellow of the American football fan.

"Did you hear that whistling " said Redskinette Karen Anctil, moments after they dropped the capes. "You hear that?"

Redskins' assistant general manager Joel Margol is worried yesterday.

"Some of those costumes have to be altered," "Four or five of the girls were in them a little too far, if you know what I mean."

And there's the tan-line problem. The back of those new red-fringed, crocus-yellow uniforms is scarcely more than an afterthought, leaving twin triangles of untanned tushie in view. Some crowd debate also centered on the diamond-shaped panel which unleashes the naval as part of the Redskinettes offense against the rest of the league.

Up in the top tier on Sunday, Buck Meier of Silver Spring squinted out under his silver crewcut and over his beer belly."Definitely," he said.

Down on Halston Alley, in the mezzanine boxes, double-taken matrons wielded their most crushing sighs, one of them even warning: "I certainly hope we won't see those costumes again next week."

Mary Jo Horan, who gave her occupation as "mother of six." countered: "Why not? We want ours to look as good as Dallas."

In any case, the Redskinettes are making their bid to join the race which the Dallas Cowgirls have been winning big, with ever-closer competition from the Denver Broncs' Ponty Express, the L. A. Rams, Embraceable Ewes, the Buffalo Bills' Jills, the Miami Dolphins' Starbrites, the Chicago Bears' Honey Bears, and the Oakland Raiderettes, among others.

Dallas: The Redskinettes hate the word - they get so sick of telling friends that they work this hard, three and four hours every Wednesday night starting in April, fighting through 200-girl tryouts, sweltering in the D.C. armory . . . and then the next word out of everybody's mouth is "Dallas."

"We're different type of organization than Dallas," insists Redskinette captain Brenda Mosley, a D.C. probation offier. "I hate to see us copying a style, I'm a bit of a conservative on these uniforms, but the fans will like them."

Says Margolis: "In today's market, the old uniforms were conservative. We're not gonna be left behind."

In one of those mystifying generational leaps that takes us from Mozart to Beethoven, trench warfare to blitzkrieg, adding machine to IBM 360s, cheerleading has just vaulted into the future.

"Cheerleading is becoming nothing more than a battle of bellybuttons b-bs and bottoms," says Bill Allen, once head of the Dolphin Dolls, a teen pep squad that got blindsided by the callipygian Starbrites.

Esquire put the Cowgirls on its cover last October. Last week ABC billed them as "the 36 Most Beautiful Girls in Texas" in a TV special. Cheerleaders are the biggest publicly acknowledged sex symbols since T-shirts started jiggling on television.Not that male minds haven't always been getting permanently scarred by blinding flashes of tights as cheerleaders arched impossibly high into those flame-blue antumn skies over the eternal high school football field . . .

But, as usual, it's not the heat, it's the publicity that bothers guardians of virtue. It's gotten so bad that Lawrence Herkimer, president of the National Cheerleaders Association, simply denies that the problem exists.

"They aren't cheerleaders," he says. "Most pro groups are dancers and performers. But they don't lead cheers, so they aren't cheerleaders."

Then again, you understand the size of the tradition Herkimer hopes to protect when he tells you that his clinics train 100,000 cheerleaders every year in 44 states, plus Canada, Switzerland and Colombia. His company, Cheerleaders Supply, does $10 million a year, he says, in sweaters, skirts, dyed-to-match saddler oxfords and pompons, on which Herkimer claims to have the patent.

"For 15 years after I started in 1951, I was the only one in the business. I must have 20 competitors, now." Cheerleading may be growing, but he's glad to say that the pro trend toward sexiness is not in high schools and colleges. "We try to avoid being in poor taste," he says.

She's gonna break it down

and do the Charlie Brown,

she's gonna shake!

Out here at Coolidge High on a Saturday morning, Donna, Chi Chi, Sillete, Nell, yvette, Sharon, Michelle, Beverly, Pam, Sandy and Terri may be stunningly demure in their black and white saddle shoes, orange jumpers and white shirts with the sleeves rolled up. And the football team may be losing a slow, miserable grind with St. John's.

But just now the crowd erupts with astonished whoops as the girls take turns stepping in front of their line-up and, well, shaking - a mere touch of the hand to the back of the head, just a couple of hip shots and they cartwheel away, but no doubt it:

Get down, get down,

She's gonna shake!

Up in the stands, Miss Sylvia Liggins, faculty sponsor, give this number a very hard stare, indeed. "We'll be making some changes," she mutters.

No doubt about it, these girls move with a fine ease and style that seems intended more to elevate the tone of the crowd than arouse it. Coolidge's cheerleaders' feet check in with the ground every once in a while out of mere courtesy, it seems. So when a soupcon of eroticism enters, it burns so bright it's almost comical, framed by this grace, this stunning innocence. They don't need diamond-shaped navel panels, or white go-go boots.

Nor, of course, do the University of Maryland cheerleaders, an hour and a half later in College Park, at the Tulane game. They're taking the more traditional white tack; rousing the crowd into the sort of bawling frenzy you need, say, to break down doors.

Clearly, pro improprieties haven't hit Maryland either.

GO BACK! GO BACK! GO BACK INTO THE WOODS!

Sharon Rhoda wears this huge astonished smile as she punches her pompon at the crowd like Dinah Shore telling you to see the U.S.A. in your Chevrolet. Jean Borne is prompting avalanches of cheers from the mountainside of people above her with her Farrah Fawcett wraparound grin.

As Sally Holtgrewe was eager to remind a listener before the game: "Our style is different from the Cowgirls - we're not the go-go boot type."

Certainly not. What's more, half the Maryland squad is male, and cheerleader Rachel Giove is polite enough to point out, "It's not true that they're just there to lift the girls up in the air."

What would an anthropologist make of these lifts, though? After every touchdown, the boys lift the girls up in a pose that looks like a combination of a hood ornament on a 1937 Packard and a sacrificial victim on a Mayan altar. The girls are symbols, they are offerings, they are - just possibly - the point of this whole beef-smashing steroid adrenalin madness taking place on the field.

They are, it would seem, the prizes, for an instant, and as such gain their stunning desirability to a lot of the male fans. It's the lure of the unobtainable, because if they're prizes, you have to be a winner to have them, and fans don't win football games.

That, and the fact that leaping in the fall sunlight, tucking their white sneakers back behind their thighs, smiling and bouncing, they look so incredibly happy - and nothing, ultimately, is more socially or sexually attractive than a truly happy human being.

Of course, the minute you come down out of the stands and get close, you see that you're tired, and sweating, and mad at the fans who throw ice cubes at them . . . and they aren't any more a prize than anyone else.

This may be why the pro cheerleaders are stunning American males into moans of appreciation. (A way, in itself, of advertising one's manhood.) Mostly, they see them on television, where they are so close, and yet so far.

You're never going to see the Redskinettes in your History 301 class, or a fraternity party either. They're mothers and legal secretaries, and probation officers and, yes, grownups - citizens of the real world, just like those mercenaries out there on the field. They don't need symbolic prizes, they're in it for the bucks, trading their knees for the best money a lot of them will ever make.

Consequently, for all the new uniforms, there is something just a touch forlorn about all the pro cheerleaders, nostalgia rampant. But then, if that weren't true, they'd probably seem far too sexy, even for pro football fans.