Every single body is different for many different reasons. The main reason is that the body is created to get through the day, rather than living for 100 years. If a muscle is used very often, the brain will keep that muscle in a state of readiness. This state will keep the muscle slightly contracted, and not relaxed. This is great for day to day motions. Everybody has different repetitive motion, and keeping those muscles ready to perform those repetitive tasks is a great way to perform better and save energy. However this is causing a more consistent pull on the bones they are attached to. This will cause the structure of the bones to change slightly, and alter the structure of the spine and skeleton as a whole.
If a muscle is causing rotations of the spine, there are many ways to approach it, and put it back in to place. The quickest and simplest way is to use force and the proper angle, and push or “crack” the spine back in to position. Often this will lead to relief since the structure is back into a more proper position. However, if the soft tissue (muscles and fascia) are not dealt with, it is highly likely that the bones will return to a misaligned position. Relaxing muscles using muscle energy techniques, and stretching Fascia using Myofascial techniques, is a great way to ensure that the soft tissue will not pull the bones out of position again. These techniques have been used by Osteopaths for generations, and now are just called different names such has PIR (post Isometric Relaxation) and RI (Reciprocal inhibition).
The greatest attribute that comes with Osteopathic experience is to get the patient to relax. Nothing is more important to a successful treatment then a relaxed patient who trusts the practitioner working on their body. It is never the fault of the patient when they cannot relax, It is always the fault of the practitioner. Osteopathic manual practitioners are taught many ways to relax the patient, and the experience with thousands of different patients add to the ability to adapt to every patient.