Lithe and little just doesn't cut it for some superstar women these days, as top-name celebs like Madonna, Janet Jackson and Sarah Jessica Parker build their bulging biceps, killer calves and washboard abs.

"It's the new look," said Suze Yalof Schwartz, executive fashion director for Glamour magazine. "This is the body of 2002. We've gone through different stages: Marilyn Monroe who was very curvy, Elle Macpherson, the healthy supermodel, then gaunt girl Kate Moss, and now we're seeing the next level up from really small to really small and fit."

Schwartz noted that while some of the stars look body-builder ripped, they are actually petite in person.

"These girls are size 0, and having muscles is what is keeping them from looking anorexic," Schwartz said. "People would be shocked to see how small these girls are in person."

Janet Jackson caused a stir at the recent Grammy awards, not for her singing or dancing she didn't perform but for her six-pack abs. But not everyone likes the look.

"Janet Jackson pushed the envelope it's too much," said David Kirsch, owner of Madison Square Club, a New York gym. "Guys are meant to look like guys, and girls are meant to look like girls."

Some fans agreed.

"Michelle Kwan has a great body but is still sexy and feminine, but Madonna looked like a guy during her last tour," said Lori Conte, an executive assistant in New York City.

Kirch said in 15 years of being a trainer he's never had a female client want to have her muscles look so defined — and he works with a bevy of models including Heidi Klum and Bridget Hall. In fact, he said, they are careful to make sure their workouts don't make them look too "diesel."

"They want to look soft and have nice curves. They don't want to go back to a heroin chic look, but you don't want to go the other way and look like they spend all their time in the gym," he said.

But Shawna Cordell, a personal trainer and owner of a fitness center, said the cut look is very in style right now with her clients.

"I have women clients who tell me they want Madonna arms," she said. "That's what's attractive right now, to be cut and lean and healthy looking as opposed to the starving model look."

For the famous, getting buff is about more than just being fit. In part, these former ingenues stay in shape to keep up with the next generation of stars.

"They want to compete," said Schwartz. "They have to work now to get the Britney Spears body."

Some of the stars are simply dealing with Father Time. Though they're getting older, they still want to maintain a rigorous lifestyle and career.

"A lot of it is driven by what happens to our bodies as they age," said Cordell. "When you hit your late 20s, early 30s and things start to sag a little, and you notice some extra fat that won't go away, you realize you aren't 21 anymore."

Parker will turn 37 this month. Madonna is 43 with two kids and Jackson is 35.

Mature women may be mentally and physically the best candidates for sculpting their bodies, according to the experts. "When you're older you can be more focused on what you want," Cordell said

Added Kirsch: "People that are a little older are more disciplined. They're not as involved with going out, drinking. They're eating and exercising more soundly."

Jackson has gone through a particularly marked transformation over the years. And she works hard to attain that headline-grabbing body.

In Shape magazine's Fit Hollywood issue last year, Jackson revealed her workout regime includes three days of abs, five to six days of cardiovascular and two days of upper body and legs a routine the requires extreme discipline.

"When I finally make up my mind that I want to do something, it's never been hard for me to do," Jackson told the magazine. "I've always been very disciplined."

And though not everyone likes the buff look, some fans give it an enthusiastic thumbs-up.

"Women can't overdo it when it comes to building muscle," said Bryan Williams, a Web editor. "There's just something intriguing about a woman who looks like she could kill you."