The underlying cause of Plantar Fasciitis
Our muscles, tendons, ligaments, and bones create a complicated pulley system throughout our body. No part of our body moves independently; movement or tension in one part of the body always affects other parts of the body.
When it comes to plantar fasciitis, tight lower back muscles—the quadratus lumborum and erector spinae group—pull the top of the pelvis and lumbar vertebrae closer together. This typically brings the pelvis into an anterior (forward) tilt. Tight hip flexors will also tilt the pelvis forward, and often play a role in plantar fasciitis.
An even amount of tension across the lower back might translate into plantar fasciitis pain being experienced equally in both feet. But many people have one side of their lower back or one hip that’s tighter than the other.
Imbalanced tightness in the lower back muscles, iliopsoas, and even the obliques can result in us experiencing plantar fasciitis pain more in one foot than the other. That’s what happened with me, and it took me a long time to figure out that my tight iliopsoas on my right side was hiking my right hip up, causing tightness all the way down my right leg that resulted in plantar fasciitis pain in my right foot.
So, when our pelvis is tipped forward, or when one hip is hiked up, our hamstrings get pulled tight. Our hamstrings originate at the bottom of our pelvic bone, run down the back of our thighs, and insert at the tops of our tibia and fibula, the bones of our lower leg.
The tension in our hamstrings pulls on the bones of our lower leg, trying to flex (bend) our knees. This attempt to flex our knees recruits the muscles of the lower leg that flex the knees as well—the gastrocnemius and the plantaris.
The gastrocnemius and the plantaris attach to the calcaneal (Achilles) tendon, which attaches to the heel bone. So when these muscles are tight, they not only flex the knee, but also plantar flex the ankle.
This finally brings us to the plantar fascia, the thick band of connective tissue that runs from the heel bone to the base of the toes, supporting the arch of the foot. When the ankle is plantar flexed, the muscles and connective tissues on bottom of the foot are tightened.
If all of this occurred while we were lying down, we probably wouldn’t feel any negative effects. But if this pulley system I’ve described is chronically tight, and we spend a lot of time on our feet, pain in the plantar fascia is almost inevitable: it’s bearing the weight of our entire body while being pulled tight.