Knuckle-cracking is actually good

[LordOfMud]

FYI

What causes the crack            

Beyond the good and bad of knuckle-cracking, Boutin and Szabo wanted to know what exactly is going on inside a joint that's being cracked.

Looking at the ultrasounds of 400 knuckles, the researchers saw something striking: When a knuckle cracked, there was a distinctive and sudden flash in the joint.

They think what's happening is that when you crack a knuckle, you're pulling apart two surfaces of the joint, which brings down the pressure in the joint. That negative pressure allows gas that's dissolved in the fluid in your joints to be liberated, and the bright flash is a gas bubble forming.

A joint gets more range of motion after you crack it: There's something about lowering the pressure that allows for more laxity.

The mythology behind knuckle-cracking

So if knuckle-cracking doesn't appear to be bad for you, how did it develop such a bad rap?