The basic concept of PRI is grounded in the understanding that the human body is not symmetrical.  The neurological, respiratory, circulatory, muscular and vision systems are not the same on the left side of the body as they are on the right, and vice versa.  They have different responsibilities, function, position and demands on them.  This system asymmetry is a good thing and an amazing design.  The human body is balanced through the integration of system imbalances.  

 

Imbalances and typical patterns associated with system disuse or weakness can develop because of dominant overuse.  This dominant overuse of one side of the body can develop from other system unilateral overuse. 

When these normal imbalances are not regulated by reciprocal function during walking, breathing or turning, a strong pattern emerges creating structural weaknesses, instabilities, and musculo-skeletal pain syndromes.  Balancing muscle activity around the sacrum (pelvis), the sternum (thorax) and the sphenoid (middle of the head) through a PRI approach best positions multiple systems of the human body for appropriate integrated asymmetrical function.