An anonymous reader quotes a report from NBC News:
Two researchers who took science to the amusement park say they've found that a thrilling roller coaster ride just might help people shake out pesky kidney stones. Dr. David Wartinger of Michigan State University said he'd heard patient after patient tell him about how they had passed kidney stones after riding one particular ride: the Big Thunder Mountain Railroad roller coaster at Walt Disney World in Orlando. He and a colleague, Dr. Marc Mitchell, had also seen some media reports about people who passed kidney stones while bungee jumping and riding roller coasters. So they decided to leave East Lansing to head to Orlando in the name of medical research. To simulate the human body as best they could, they made an artificial human kidney model out of clear silicone gel and loaded it up with real human kidney stones. They rode the roller coaster holding their kidney contraption between them in a backpack positioned at kidney height. They took 20 rides and noted what happened to each kidney stone. Riding in the back of the roller coaster train seemed to really knock the kidney stones out, they reported in The Journal of the American Osteopathic Association. "Front seating on the roller coaster resulted in a passage rate of four of 24," they wrote. "Rear seating on the roller coaster resulted in a passage rate of 23 of 36." They mainly tested the one roller coaster ride, and it's a fairly simple one. "The Big Thunder Mountain roller coaster is not a terribly dynamic ride," Wartinger said. "It's not very fast. It is not very tall. It makes sharp left and right turns that have some vibration." Wartinger suspects many different thrill rides would have the same effect. "It's not like there anything unique about this one coaster," he said. The pair have now run their test 200 more times and say the findings are consistent. Now they want to try other amusement park rides.