In case anyone skips reading the article this was of particular interest

" she's heard of improvised experiments. Weightless, the astronauts remove their garments when they feel a big blow coming and, to quote American astronaut Roger Crouch, use intestinal gas as a propellant to, "launch themselves across the middeck."

Roach e-mailed Roger Crouch to ask if this had ever really happened. He was coy:

"He had heard the claims and was dubious. 'The mass and velocity of the expelled gas,' he told me in an e-mail that has forever endeared him to me, 'is very small compared to the mass of the human body.' Thus it was unlikely that it could accelerate a 180-pound astronaut. Crouch pointed out that an exhaled breath doesn't propel an astronaut in any direction, and the lungs hold about six liters of air versus the fart, which, as we learned from Dr. Murphy, holds at most three soda cans worth.""