Traveling space and knuckle cracking doesn't mix!
Found a funny comment by Carmine6 on thaivisa.com that NASA won't take your application when you confess to crack your knuckles:
A few years ago there was a tv show about astronauts and the head Dr. at NASA said you can't crack your knuckles and be an astronaut, they want nice tight joints. Not sure if that's true anymore and they have special needs with low gravity environment.
zging knows why:
The reason why cracking knuckles etc. feels good is that buy forcing these bubbles to burst you're lowering built up pressure within your joints (hence why tight joints are important for space go-ers. expanding gas in the low pressures of orbit could cause problems 8O) and also STRECTHING muscles and ligaments (mild stretching usually feels good). This IS good for the health and general fitness, as it increases your bodie's flexiblity, circulation etc.
Which suggests that joint cracking isn't good then? :?