Was forwarded a great article today about what astronauts do to keep their muscles active when in space. Story at FloridaToday.com
A bunch of surprising statistics given in the article including the amount of exercise needed on daily basis to prevent muscle atrophy: 2 1/2 hours daily! Given how busy the astronauts seem when they've conducting missions, it's a wonder they have the time to fit in exercise.
I had heard in the past about the effects that zero gravity had on the body, particularly the back/spine, but had never read much on what steps are taken to prevent it.
Make sure you check out the descriptions of some of the equipment used - very impressive stuff - from the article:
"...they can use the TVIS (Treadmill Vibration Isolation System), a free-floating treadmill held together with bungee cords. The astronaut straps into the TVIS and literally goes for a little walk around the Earth."