Under Armour CEO Calls Adidas ‘Our Dumbest Competitor’

Under Armour is talking trash about its German rival.

"We're not going to compete with our dumbest competitor," Under Armour chief executive Kevin Plank said in an interview on Bloomberg Television, referring to Adidas AG's push for more athletic sponsorships to shore up its flagging U.S. business.

When asked again if he thought Adidas was his dumbest competitor, Mr. Plank doubled down. "I don't like them," he said. "I don't like the other guys either, but that's my job."

The public diss of Adidas comes after Baltimore-based Under Armour Inc., a relative newcomer to the athletic apparel industry, surpassed...