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. (1)
The physical medicine discipline taught by the Postural Restoration Institute located in Lincoln Nebraska goes by the acronym PRI. PRI is not about “standing up tall.” Rather, it is about neuromotor balance between the left and right side of the body. When imbalances occur in the body, joints, bones and muscles are affected, resulting in pain in various yet understandable places. (2)
Due to these postural asymmetries, there are common patterns that exist in all humans that contribute to our individual pain symptoms. How people compensate for this pattern can vary; however, the underlying dominant pattern exists in everyone. We all tend to stand on our right leg more than the left. Whether right or left handed, our right leg is our dominant leg.
These tendencies have been with us since the beginning of human movement.
Even Superheroes can’t help but favor their right leg.
We have a liver on the right side that weighs three to four pounds, and on the opposite side, we have a spleen that weighs less than a pound. We have three lobes of lung on the right and only two on the left. In our upper trunk, we have a heart that lies more to the left. This organ asymmetry coupled with gravity, environmental factors, primitive reflexes and vestibular imbalances results in a tendency to stand on our right leg and rotate our upper body to the left.
What Does Asymmetry Look Like?
Integrating PRI principles and philosophies into the Ultimate Program’s exercise selection, modifications and progressions will allow the program to address the general needs of the asymmetrical human body.
1) Basics Concepts of the Postural Restoration Institute; Ron Hruska; www.posturalrestoration.com
2) Understanding Postural Symmetry to Improve Performance and Injury Prevention; Lori Thomsen; www.hruskaclinic.com