Michael Phelps is an American swimmer that won a combined 16 Olympic medals from the 2004 Athens and 2008 Beijing Olympic Games. Here at Under Armour's global headquarters, Phelps starts his day very early in the morning with current trainer Keenan Robinson. Although four years have passed since his record-breaking performance in Beijing, Phelps seems more focused than ever as he prepares for the upcoming 2012 London Olympic Games.

Reporter: Yuhan Liu

Video: Derek Bosko

Photo Research: Chen Ziyan, Guan Xiaomeng

Supervising Producer: Flora Yue & Calvin Zhou

Senior Producer: Larry Lee & Ji Tao