The inhabitants of the International Space Station often spend six-month stints aboard the satellite. Consequently, they are faced with certain medical problems from living in long-term weightlessness. Some of the symptoms of space life include muscle atrophy and reduced bone dimension. To minimize the ill effects of space, astronauts often work out on a treadmill or stationary bike. One of the treadmills is named for TV host and comedian Steven Colbert after his fans pushed to name a module after him. Pictured here is astronaut Sunita L. Williams, who works out equipped with a bungee harness on the Treadmill Vibration Isolation System (TVIS) in the Zvezda Service Module of the International Space Station.