Move over, Madonna. Michelle Obama’s got guns.

Since she walked into the White House, Obama has selected fashion-forward clothing that flatters her buff arms. She’s on the current cover of Vogue sans sleeves. She wore sleeveless Narciso Rodriguez to the president’s joint session of Congress last month. And she was on a March cover of People magazine in a pink lace dress also lacking sleeves.

Obama has been a fashion icon since she hit the campaign trail two years ago. But the first lady’s toned triceps have received more attention of late. Two weeks ago, she even defended her right to bare arms — a few naysayers have criticized her for showing the skin — on “Good Morning America.” But, most of the attention has been positive. Just in time for spring, Obama is motivating women to get in shape.

“Obama’s arms are popular because she’s not too skinny and she’s not overly muscled,” says Rylan Duggan, a British Columbia Registered Kinesiologist who blogs about defining flab by arms at gosleevelessblog.com. “She’s lean and toned yet still feminine.”

Clients who normally ask for Madonna or Kelly Ripa arms have added Obama to the list, Duggan says. He believes women want to emulate her because she is a busy woman rather than a twenty-something starlet. “She’s the family woman. She’s showing people you can have a great body and be a busy mom.  The women I work with are so proud of her for being able to do that. I think it’s fantastic.”

The only thing we know about Obama’s fitness regimen is that she works out with a personal trainer for 90 minutes three days a week. But what does she do to build those biceps? Duggan’s analysis: “I can assure you that she’s not afraid of lifting heavy weights,” he says, adding that many women avoid heavier weights for fear of bulking up.

Duggan, a certified strength and conditioning specialist, is also confident that Obama’s trainer has her on interval training, or bursts of high-intensity cardiovascular exercises followed by minutes of lower-intensity activity. “It’s the most efficient way to work out because you save time, burn more fat and boost metabolism.”

Finally, he says, Obama’s getting buff by working her whole body. Hard. You can do hundreds of bicep curls a week, but if you’re not engaging your entire body, you won’t eliminate those bat wings, Duggan says. “Spot reduction is a myth,” he adds. “The only way to burn body fat is to lose it from your whole body.”