Good news for knuckle-crackers
You may have heard that knuckle-cracking is bad for you, but studies have shown that knuckle-cracking is actually good for you.
Dr. Robert Szabo, who is a hand surgeon, and his colleague Dr. Robert Boutin, a radiologist at UC Davis, collaborated on a knuckle-cracking study.
According to CNN.com, the idea was to gather a bunch of knuckle-crackers and have them do things under an ultrasound to see what was really going on inside the joint. They then examined the knuckles pre- and post-crack, along with the knuckles of a group of non-crackers, to look for problems, including hand swelling and any decreases in grip strength.
The results were shocking. The knuckle-crackers didn't have any hand problems. In fact, after someone cracked a knuckle, it had an increased range of motion compared
with knuckles which hadn't been 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.
The researchers believe 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 released, and the bright flash is a gas bubble forming.
"After reviewing the science, I believe strongly that it's not harmful," said Boutin.