Manipulation
When an osteopath or chiropractor manipulates a joint with a high velocity, low amplitude thrust, the practitioner is not putting your joints or vertebra back in place.
The practitioner is simply moving a joint between the physiological barrier and/or the restrictive barrier and the anatomical barrier.
This procedure is more often used to increase the range of motion of stiff joints.
The manipulation causes a neurological silence (i.e. no information from the joint is going to the spinal cord or brain for about 20 minutes). For example, it's just like pressing the reset button on the computer. The computer needs to "re-boot". When the joint has been manipulated (re-booted), the result is an increased range of motion of the joint. The muscles that control the joint have been "reset" to a more normal resting length. This in turn will help normalise structure and function and aid in a return to homeostasis (normal function).
In simple terms, if your joints and soft tissue move better - they push out waste products and draw in nutrients which aids in growth and repair.