The left AIC right BC pattern is a neuromuscular pattern of activity that correlates with having too much neurological awareness of the right side of your body.
In the left AIC right BC pattern, your brain’s awareness of your body’s joint position and muscular activation becomes rightward biased.
This is due to a host of factors, including breathing and brain function, but it is also from an overstimulation of mechanoreceptors that populate the joints/muscles of the right side of your body and under-stimulation of those on the left.
Left AIC Right BC Pattern and Mechanoreceptors
Mechanoreceptors are sensory neurons that respond to mechanical pressure of distortion. Together, they provide a sense of joint position to your brain so it can make decisions on how to organize muscle function. They give your brain a sense of “where you are, what you are doing, and where you are going”.
The mechanoreceptors include:
- muscle spindles,
- golgi tendon organs,
- Ruffini endings,
- Pancinian corpuscles,
- Golgi-Mazzoni corpuscles
At the joint level, you could say that the left AIC right BC pattern is a pattern of mechanoreceptor induced right-biased positional awareness distortion that becomes “encoded” in the central nervous system as normal.
Right Grounding with Left Rotation
Accordingly, since this distortion is accepted by your brain as the norm, your entire body becomes oriented to the right when it is upright and walking.
But since you have to walk straight, you have to counter-rotate your body back to the left in order to stay straight.
This compensatory counter-rotation back to the left is why your left leg gets stuck in a state of external rotation and your right leg gets stuck in a state of internal rotation. It’s also why so many people notice a rib flare on the left side, and a left shoulder that is higher than the right shoulder.
These altered states of proprioception lead to abnormal joint mechanics and muscle activity that then have to be controlled for by compensatory muscle activity.
This is where so much joint and muscle pain comes from.
In the Youtube video below, I demonstrate how getting someone neutral, meaning an individual is passing all their PRI tests, is more about what someone is sensing, rather than a muscular task.
Understanding that an individual laying down on your table is oriented to the right and living in a state of continual counter-rotation back to the left changes how you interpret bio-mechanical range of motion tests.
You realize that range of motion limitations are NOT due to tightness, they are due to the abnormal position of the pelvis and ribcage. So there is nothing to stretch.
In the left AIC right BC pattern, right shoulders often lack internal rotation, left legs often can’t adduct, right legs can’t abduct, and necks can’t side-bend to the right.
All of those tests are limited on the individual in the video because she is in the left AIC right BC pattern and thus living in a state of rightward orientation.
All her tests are consistent with someone who is, from a bio-mechanical standpoint, living in the right stance phase of gait (left AIC right BC pattern).
These limitations should exist when someone is standing on their right leg.
However, they shouldn’t exist when someone is laying down on the table at rest.
Why would my friend be limited in right stance ranges of motion when she is laying down at rest?
It’s because of the left AIC right BC pattern and the muscle activity that goes along with that pattern.
In order to inhibit (turn “off) her left AIC right BC pattern, all I have her do is flip the script.
I put her in a right AIC left BC pattern. This pattern equates with “left stance” phase of gait.
I have her sense
- the position her body is in.
- her bodyweight more concentrated on the left leg
- her left heel and the arch of her right foot, which changes her experience of the ground.
- rotation of her torso to the right
I use her nervous system’s inherent function, the mechanoreceptors in the skin of her feet and proprioceptors located in her muscles, joints, and ligaments, to give her brain a new sense of position: left stance.
This process, of sensing, of being in touch with what her body is doing, turns off the left AIC right BC pattern and lets her body rest in a state of neutrality.