For some people it is a habit they think very little about but for researchers at the University of California, Davis, knuckle cracking posed a few curious questions. Why do joints 'pop' and does it actually do damage? Their findings were nothing short of fascinating! They began their study by running tests on the hand strength and flexibility of 40 men and women. The volunteers then underwent ultrasound scans while attempting to crack the metacarpophalangeal joint (MPJ) which is the large knuckle in the middle of each finger. Some of the volunteers were regular, habitual knuckle crackers -- doing it upwards of 20 times a day for 40 years, while others had never tried it before. The volunteers cracked 62 of 400 joints. By using a small transducer, a sonographer recorded video of the joints as the participants attempted to crack them as well as static images of the MPJ before and after the cracking attempts. Orthopaedists, who knew nothing of the participants' knuckle cracking history, examined their grip strength, range of motion and laxity in the MPJ before and after the ultrasound. What they found was that the knuckles that were popped were no more swollen, painful or weaker than those that were not. The ultrasound also revealed that each crack was accompanied by a flash of light!
"What we saw was a bright flash on the ultrasound, like a firework exploding in the joint," researcher Robert Boutin said. "It was quite an unexpected finding."Have a look for yourself: https://youtu.be/bvtdCLiev3A [bctt tweet="Ultrasound Shows EXACTLY What Happens When You Crack Your Knuckles (VIDEO)"] Boutin believes that both the flash of the "fireworks" and the crack are caused by the pressure in the fluid that surrounds the joint suddenly dropping as the two ends are pulled apart, which creates a bubble. While it might not be that interesting to you, scientists are engaged in a hot debate over whether or not the noise comes from a bubble popping or a bubble forming. What do you think of these findings? Are you a knuckle cracker? Are you pleased to learn that you aren't doing any immediate damage to your joints? Source: Daily Mail [caption id="attachment_121550" align="alignleft" width="100"] @BodyRockTV[/caption] [caption id="attachment_121549" align="alignleft" width="100"] @BodyRockOfficial[/caption]