Can you adjust your own back?

When your muscles are relaxed your spine may "crack" (what doctors of chiropractic call "release") on its own when you bend, twist, etc. This is simply the release of gases from the joint space, and is no different than cracking knuckles, etc.

It should be noted that research has suggested that the "cracking" sound that comes from "cracking" a joint has no therpeutic benefit in itself. It seems that it is the high velocity and low amplitude stretch of proprioceptive musculature that surrounds the joint that induced the therapeutic effect. Thus, simply "cracking" your own back by twisting yourself or squeezing a friend will not result in the same benefits of a proper adjustment by a skilled professional such as a doctor of chiropractic, who have attended at least 8 years of post secondary education to perfect this technique.