Cover Story: Growing Up With Under Armour

"The reason for Under Armour's success is it's always maintained a focus," says Niemuth. "It's always been about performance and aggression. All of the products it sells somehow help you improve your performance on the field. They don't just help you play … They help you WIN."

As it gears up for continued growth, Under Armour continuously seeks more ways to contact and connect with younger audiences. Although it doesn't use its catalog as a prospecting tool, Under Armour takes advantage of multiple other channels to recruit new customers. The company's retail stores and wholesale partners serve as acquisition sources; display ads, affiliate marketing and search account for the majority of its prospecting efforts online. —Additional reporting by Paul Miller