In the Washington Post this morning, this article:
"What if you could burn fat while shaking a martini? Actually, it's your body that shakes like a martini on a new type of fitness machine that's generating lots of buzz and celebrity use. Even NASA has tested the concept.
These machines use vibrations to tone muscle and claim to do it faster. Aggressive promoters also say the equipment improves flexibility and strength, reduces pain and stress, builds muscle and reverses osteoporosis.However, researchers warn of possible injuries ranging from back pain to cartilage damage. One even warns that the high-powered jiggling might harm the brain. They say the science is thin and too little is known about the long-term effects of such powerful vibrations.Still, NASA is studying vibration as a possible tool for reducing muscle atrophy and bone loss during astronauts' long, weightless trips in space."
Rest of the article here.