Happy Tuesday, everyone.
Welcome to the next episode of the podcast.
I had some people message me and they really wanted to learn and understand how the feet can cause lower back pain, from a biomechanical standpoint.
In today’s podcast, I did want to talk about part one of it because this is going to be a multi-step episode, or episodes rather, of how your feet can cause lower back pain, and so I think a few things we need to begin with first off is the end in mind.
Before I disclose the mechanics of it, we need to really understand what is the function of foot in regards to gait?
As you take a step in gait, a heel strike and basically want to absorb those forces.
It needs to become a shock-absorber during this phase, but it also needs to become a torque converter. That’s where the eversion of the heel in the subtalar joint and then getting the foot flat to get pronation, which then causes rotation up the chain.
We’re trying to create force in rotation.
Then conversely, on the other end of the spectrum, when I step through in gait and get ready to propel, we want the foot to be stable in a rigid lever, so we can propel off of it.
If you can understand those concepts, then you’ll can kind of understand why certain types of feet cause lower back pain. Let’s start off with the first type of foot that typically will cause lower back pain.
This is what we call a forefoot valgus foot. This is someone with a forefoot valgus or a pes equinus foot, and so these are your people that are super high arched.
They have no pronation typically at all. You’ll usually hear them walking towards you. These are the people that I kid with that you can throw quarters underneath their arches because they’re that high.
They just don’t have any shock absorption.
These are the people, they’ll get the lower back pain for a couple of different reasons. Typically, again, the first one is shock absorption. These type of people don’t have the ability to absorb shock.
During the loading response, they’re not getting any pronation and they’re not getting, typically, any rotation up the chain at the hip to take stress off of their back.
Again, you’ll watch them walk and you’re just not going to see any pronation.
Now, on the other end of the spectrum, when you go through in terminal stance, typically they’re not getting any hip extension because they have lack of ankle dorsiflexion.
It’s more, again, of a pes equinus foot at the same time, so their dorsal flection is just limited as well.
Because they’re not able to get dorsiflexion at the foot and ankle, they’re going to have early heel rise, which is also then going to limit potentially the amount of hip extension that they get.
Sometimes you might see them even in somewhat of a functional limitation of hip extension or anterior pelvic tilt, which then can cause compressive forces in the spine.
Instead of getting hip extension, they may get lumbar extension.
Again, I think to recap today, we want to begin with the end in mind.
If you know what the function of the foot is, you can trace it up or down into the back. Today, we talked a lot about what they call a forefoot valgus type of foot or pes equinus foot. They usually go hand in hand. These are your high arch people.
They lack shock absorption, so in loading response, they’re not getting any pronation.
Those forces have to be directed upwards and they’re not able to absorb them, so they typically go through the spine.
Also, in that same token, they’re not getting any rotation because they can’t really evert, so they are missing out on that plane of motion.
We know that the butt muscles and the hip love internal rotation to help absorb it and they can’t.
Now in terminal stance, they usually will get early heel lift.
That’s because, again, they have lack of ankle dorsiflexion from the pes equinus.
They’ll have super tight calf potentially, but then they’re not able to get through their hip. Instead of getting hip extension, they’ll get lumbar extension.
Stay tuned for the next episode where I go over the next type of foot that causes lower back pain and how you can treat it.