Squat Report: The Foot
Every year we are going to look, in detail, the forces that are going through our bodies when we do any exercise. This year we are going to dive into the squat. Every month we are going to look into all the joints that are being influenced and how they play a role for us to preform the required task.
We are going to look at three different positions of the bar that you can place on your body and how the actual placement can affect the different muscles and firing patterns that are required.
In the case of the squat you can place the bar in three different positions. You can place it:
In the front:
On your back:
Or above your head:
Now before I continue I really need to stress this point: I am going to assume that there are now injuries on this “virtual person” that we will be discussing it will be a middle age male, 200 cm tall, and weighs 200 lbs. Why is this important? Well we need to understand who we are training. Men and women are physically, and chemically different and “changes” how we assimilate the data when preforming exercises. Not only this but also the forces that go through our bodies also differ. And the fact that this person has never been hurt before in his life the joints will function as default with no muscular imbalances to take under consideration.
So, let’s get on with it.
This section will take into consideration all three positions of the bar as the forces change, the positive is that we can look at is at the foot (mid foot and fore foot not much changes but there are some differences when it comes to the hind foot)
During a squat on the downward motion of the movement, I don’t like using concentric or eccentric because their definition concentric means to contract during a movement and eccentric means to lengthen during a movement, hence your hamstrings and quads are doing both movements throughout (quads are contracting at the hip and extending at the knee, and hamstrings are doing the opposite behind the leg) during the downward movement of the squat.
In the forefoot, where we are looking, the metatarsals want to collapse inward and the phalanxes want to come together as you go further into the squat. Your arches will tend to collapse, so this is where the smaller foot muscles will come into play.
Let’s start at the toe’s (for the following explanation please refer to last week's post on anatomy).
The flexor Digitorum brevis will fire along with abductor digiti brevis and quardratus plantae to keep from having your toes from flying up into the sky. Also, you will have the lumbricals controlling the metatarsophalangeals and the interphalangeal firing, also you will have every single foot muscle firing to keep your foot from coming apart the deeper you get into the squat.
Now the one major fact that we usually don’t take into consideration is the resistance factor that the ground gives us. Only because this becomes more of a “player” during the upward movement and we will look into that later, but for now just try to understand that gravity is trying to push you “up” in a sense acting as breaking effect.
Now with the bar on the back (traditional squat) or overhead it really doesn’t play that much of a difference, just the numbers but we won’t go into that because we can all get lost with those so let’s move on the mid foot.
Now there are some interesting things that happen in the mid foot during the downward phase of the squat. Starting from the navicular bone to the cuneiform bones
The Navicular Bone takes the stress forces that come down from the Talus and disperses these forces to the 3-cuneiform bone. This pushes the navicular bone upwards so the extensor digitorum muscle has to fire to keep the navicular bone from popping up which forces the foot into dorsi flexion (foot flexes up). Also, the tibialus anterior muscle has to fire in sync with the extensor digitorum as the forces are extreme at this point of the squat.
The Cuboid also takes the same forces and disperses them to the 4th and 5th metatarsal, please keep in mind that the same muscles fire for this process as well.
From the navicular the stresses now move into the 3 cuneiform bones except for the third cuneiform bone where (this is one of the two places in the body that this happens) actual shear forces may happen because of the geography to the cuboid. Again, the same muscle covers these bones.
The hind foot is made up of two bones the talus and the calcaneus. The talus receives the stresses from the tibia and fibula, the calcaneus receives the majority of the stress from the talus, however, the fibula also sits on the calcaneus. This is important to know as if there is a splice in the distal (furthest away from the body) aspect of the shin if these two bones are not properly sitting together it may cause the muscle and tendon structure not to function properly. I went into all of the 18 muscles last week on the foot so just to sum up we are looking at dorsiflexors of the foot (try it while you are reading this just lift your foot up) you have the peroneus longus, and brevis, anterior tibialus, extensor digitorum longus and brevis, and extensor hallicus longus all fire in the motion of dorsiflexion when you are in the downward phase of a squat.
Plantar Flexion Phase
When you are at the bottom of the squat and you want to come back up, your foot goes into what is called plantar flexion (it pushes into the ground) even more interesting things now happen at the toes.
Your toes want to extend, your arches go down, and your foot drives into the ground.
Here is where friction really plays a major factor, if for example you were doing a squat standing on an oil patch (not recommended) you would fail and most likely end up in the hospital. But at a muscular point of view all of your foot muscles would have to contract in order to help you keep the traction on the ground and keep your foot intact. The major movers here are pretty much the same as when your foot goes into dorsiflexion as there are some very minor changes in forces acting on the foot, it pretty much acts the same.
At the midfoot in plantar flexion the major muscles that act on keeping the arch up in a “normal” position these muscles are in the actual shin and ankle portion which we will discus next week. But because the muscles here don’t really change that much we can keep it short, some points to take into consideration, however, are the quardratus plantae and the flexor digitorum brevis, adductor hallicus, plantar interossei, and flexor digiti minimi brevis all a have a massive role to play when you are in the upward phase of the squat to keep your foot intact and a stable foundation.
At the hindfoot during plantar flexion even more interesting things happen when the foot is anchored to the ground. Because when all of your energy is going to your toes Newton’s 3rd Law of motion comes into play (every action has an equal and opposite reaction). What does this mean, well in lameness terms your toes are driving into the ground, so your heel will want to lift off the ground, and when your heel drives into the ground your toes lift off the ground. Don’t believe me, try it for yourself, as you stand up drive your heels into the ground and see what happens to your toes. In order for this not happen we have a multitude of muscles to help us counteract this effect. The majority of these muscles reside in the back of the shin and they are extremely powerful muscles. We will look into these next week when we dive into the ankle. For now, we will merely identify them as the gastrocnemius, soleus, tibialis posterior, flexor digitorum longus, and flexor hallicus longus.
Now the good thing about this is, as I said before, the placement of the bar plays an extremely minimal role as the differentiation of what happens at the foot, the thing that is important is when the total mass increases. If, and when, this happens it changes the forces in the muscles and the foot have to work harder, this becomes an issue when there are muscular imbalances at play, considering there are none we have no problems to worry about.
Next week we take a deeper look into the ankle and see how that joint plays a role in the effectiveness of the squat.