Left-Sided Back, Neck, and Knee Pain: Why It's So Stubborn

Management of Left Sided Pain

The human body has two primary breathing muscles. The right and left diaphragms. These two diaphragms, while having the same job, are not the same in structure or efficiency.

The right diaphragm is bigger, stronger, and better leveraged to pump air.

The left diaphragm, compared to the right diaphragm, is smaller and weaker, with less mechanical leverage to pump air.

The diaphragms have vital responsibilities beyond breathing. They also guide the overall movement of our body, particularly the rotational movements of the spine and ribs.

Since the rotational force exerted on the lower spine by the right diaphragm is stronger than that of the left diaphragm, our lower spine, which is also the center of our body, has a tendency to rotate to the right more easily than to the left.

As a result, our entire body has a tendency to favor the right side over the left side regardless of handedness.

Generally this natural asymmetry of movement is not a problem. But sometimes this natural asymmetry gets out of hand and our perfect asymmetry becomes imperfect asymmetry.

When we move outside our acceptable range of asymmetry, our movement patterns become so altered that the two sides of our body assume different “personalities”.

The inherently stronger right side, which already has more muscle than the left side, becomes overused, further asserting its dominance over the left by never relaxing enough to enable the left side to do its job.

The inherently weaker left side weakens further due to a constant pull coming from the overactive right side. The brain then becomes over-sensitized on the right, and under-sensitized on the left, further reinforcing the right sided dominance.


As the left-sided muscles weaken your brain is forced to utilize compensatory strategies to stabilize and move your left side.

The compensatory muscles used to stabilize and ground your left side, while quite powerful, are not designed to stabilize us for any length of time and are only efficient at moving us forward. Yet efficient human movement requires side-to-side and rotational movements.

This is where the problems occur. Compensatory strategies are meant to be short-term, they should not become normalized muscular behavior. When compensatory muscle behavior becomes the new normal, pain will result.

The key to successful resolution of left-sided pain is to “turn off” your body’s compensatory strategies and re-train proper Left Stance musculature, from the ground up.

This has to be done through:

Proper footwear

During walking, your leg muscles activate according to where your weight is placed on your feet. It starts with heel strike. As your heel strikes the ground, your left hamstring should activate and begin to pull your left pelvis backwards. If your left hamstring doesn’t activate first, compensatory muscle action will be called upon to complete the step.

To get this sequence started properly, we need stable heels. Many people wear footwear that is too loose. When a left heel is unstable, the brain senses it immediately and calls upon the compensatory left hip flexors and lower back muscles to stabilize the knee and pelvis.

If your heel is stable, you can immediately begin to recruit the proper muscles, starting with the left hamstring, and your brain won’t have to call upon the hip flexors and lower back to stabilize your hip.

All re-training must start from the ground up, and that means proper footwear to stabilize your foot at heel strike.

Left Diaphragm Activity

You need to reintegrate your left diaphragm into your life. If the heel, knee, and pelvis are stable, and the left side is thus grounded, there is no need to use your lower back and left diaphragm to stabilize the pelvis.

At that point the left diaphragm will get into the game as a breathing muscle rather than a postural stabilizer. Breathing becomes more efficient so that neck muscles don’t have to be relied upon as compensatory breathing muscles. Now painful neck muscles can finally relax.

Left Stance Strength

Then you need to train proper movement of the pelvis and ribcage, starting in supine and sidelying positions, eventually progressing to an upright position. You need to establish a new pattern of left hip movement, stability, and strength using the appropriate muscles rather than compensatory strategies.

If weakness remains, your brain will not allow your body weight to shift to your unstable left side and any progress will be quickly lost as your brain falls back upon its previous pattern of compensatory movement and stabilization.

Fortunately, PRI exercises train these functions all at once, so the biggest challenge is going from ground-based to upright activities. This is due to the fact that the more demanding the physical task, the more likely your brain is to fall back upon compensation patterns.

This is also why you may feel pain during certain activities and not others, feel great one moment and then seemingly regress out of nowhere (I know the struggle). The activity can be too challenging for your body, or the activity has lasted too long, and your brain switches over to compensation as a protective mechanism.