There are two kinds of people in the world: those who know what Under Armour is and those who are just finding out.

John Mincarelli is one of the latter, having stumbled onto Under Armour last year at a sporting-goods store in upstate New York.

Mincarelli, who teaches fashion merchandising at the Fashion Institute of Technology, is a hard man to impress. And perusing the racks of Nike, Adidas and Columbia that day, looking for some new workout gear, nothing did. But then a display leapt out at him.

"It totally grabbed my attention -- just the name alone," he said. "I thought, 'This is brilliant.' It implies all this power and protection . . . right off the bat."

Under Armour isn't new; it was founded in 1996 in Baltimore by Kevin Plank, a former college football player. But the brand hid in plain sight on the playing fields of team sports and the cameras of ESPN, where its discreet logo (a U crossed with an A) and cartoonishly macho imagery made it all but invisible to the......