Stephanie Linnartz will start work as CEO of Under Armour in late February. The sportswear brand has been without a chief exec since Partik Frisk resigned seven months ago. Ms. Linnartz comes from Marriott International where she held the president’s seat. Commenting on the strategy of bringing in an outsider, founder and ongoing executive chair and brand chief Kevin Plank said, “We’ve got enough industry experts here at Under Armour. We’re fortunate to have a leader with the perspective that Stephanie is going to bring.”