First lady Michelle Obama worked out with trainers from "The Biggest Loser" at the White House as part of her national Let's Move! initiative. Take a look at other Presidential first ladies and the causes they have supported.
U.S. first lady Michelle Obama flexes her muscles as she exercises with schoolchildren at the River Terrace School April 21, 2010, in Washington, D.C. Obama visited the school to highlight physical activity as a critical element of the 'Let?s Move!' initiative with several Olympians and Paralympians, including 2010 Olympians Shani Davis and Hannah Kearney and 2010 Paralympians Alana Nichols and Heath Calhoun.