Under Armour (NYSE: UA) (NYSE: UAA) has excelled at getting its gear on the playing field thanks to technical innovations and partnerships with high-profile college teams, as well as an upcoming tie-up with Major League Baseball. But in order for the company to make it to the next level, it will need to establish itself as a fashion brand, much like Nike (NYSE: NKE) and Adidas (NasdaqOTC: ADDYY) have — and its efforts thus far have largely fallen flat.