The answer is that we have another muscular system also pulling on our frame. This is the viscera, a collection of the organs, including the heart, arteries, lungs and intestines.

arrangement of two arms and two legs with the single bones (vertebrae, sternum, sacrum, etc.) in the center. All the muscles in this system are paired; what is on one side of your body is also on the other.

From a purely engineering standpoint such a structure would make a healthy person sit with equal weight on each buttock, with balance along the midline from tailbone to head. The shoulders and hips would be on the same plane, which would be facing forward; movement to either side requires the same amount of effort. This is a position of readiness for activity. But why don’t people do that inherently if that is how we are designed?

The answer is that we have another they affect the body’s position when at rest. Specifically, this system pulls on the body so that the left hip is slightly forward, the weight is shifted to the right, the spine curves to the left in the low back and to the right in the upper, and the plane of the hips turns slightly to the right while the plane of the shoulders goes to the left. This is the natural, and normal, resting position for humans, whether we are sitting on the couch, the car or in the saddle.

See for yourself as you sit and read this: Note where you have the weight on your buttocks, how your knees and hips are aligned and how your shoulders and head align. Next, sit in your best “equitation” form---upright, shoulders square, hips both aimed forward, equal