Put in general terms, the adjustment is a quick, low force technique applied to a particluar vertebrae to remove subluxations in the spine. These subluxations interfere with the ability of the nervous system to operate correctly. When the intereference is removed from the nervous system, the body's ability to heal is optimized.
When these subluxations are present, they have an overall negative effect in our bodies. Without proper alignment (and the removal of the subluxation) we can't function at our peak.
The adjustment happens with a quick movement and is often without discomfort. You may hear a noise that sounds like you're cracking your knuckles, which is referred to as "joint cavitation." Cavitation is the release of gases such as oxygen and nitrogen from the joint.
Overall, adjustments are an excellent way to keep the body functioning at its highest level. When interference to the nervous system is removed, the body is able to respond and perform as it was designed to.