WHAT THE FOOT?!
Confession: we at Paragon are total foot nerds. We love the feet. They tell a story (a very useful story) full of vast amounts of information. As an athlete, you’re built from the ground up. The body is a powerfully interconnected system, and your feet are the foundation. The foot is beautifully complex: made of 26 bones and more than 100 muscles, tendons, and ligaments. And it has a lot to brag about, acting as a shock absorber, locomotor, and support system, and also a major source of sensory input (which we will talk about more later). You have all probably heard us tell you about the foot tripod. It consists of the center of the calcaneus (heel), the base of the 1st metatarsal (big toe) and the base of the 5th metatarsal (pinky toe). If you have a stable tripod of the foot, then that stability can travel up the chain. So, this is a great place to start: by working on your foot tripod. Go ahead and try it. Stand up on one foot, lift all of your toes, and see if you can put even weight on the middle of your heel, ball of foot, and base of the pinky toe. Feel easy? Close your eyes and try again. Ok, now let’s get moving.
The Gait Cycle
During gait, the foot must be stable at initial foot-strike and also at push-off. However, during mid-support, the foot must become a mobile adaptor and attenuate loads. It also possesses spring-like characteristics, storing and releasing elastic energy with each foot-strike. This is accomplished through the deformation of the arch, which is controlled by all of those intrinsic and extrinsic foot muscles.
Gait can be broken down into phases:
1. Initial Contact 2. Loading Response 3. Midstance 4. Terminal Stance
5. Pre swing 6. Initial Swing 7. Mid Swing 8. Late Swing
A growing body of research shows that strength of small muscles in the foot can have big implications for a range of foot-health issues, like running-related injuries, and that interventions for strengthening the intrinsic foot muscles may help (so don’t you worry, we will have you covered with that!) Anyone out there ever been diagnosed with plantar fasciitis? Have you ever had achilles pain? Preventing and managing these injuries should start with a focus on your foot mechanics (Elbaz et at. 2017).
The body is really, really good at compensating. So if the feet are not doing their fair share of the work during your gait cycle, or in any activity, then the buck will be passed elsewhere. The load is going to go somewhere. It doesn’t just magically disappear into thin air. And our bodies are really, really strong, and will adapt. And in some cases, your body may have a bony structure that is not going to change, so we will make you stronger so that your system can tolerate your structure. But, we often see things we can change, and we think that there is an optimal, efficient way to move. We can make the foot stronger in an optimal way, just like any other part of the body.
The mighty team of the foot, ankle and hip!
Now, we hope that it is obvious that when we are talking about foot we are also talking about the ankle. We know you have heard about the importance of ankle stability and also mobility. Let’s first take a look at ankle range of motion. In a huge chunk of the population that has limited ankle mobility, that stiffness and loss of ankle rocker is actually there as a coping mechanism to find stability. Again, your foot should be a mobile adaptor, but also very important is the ability to lock off to push you through your gait cycle when walking or running. So, if you don't have a stable enough foot/arch and are passing your body mass over that unstable structure, collapse ensues before ankle rocker is completed during stance phase of gait (Cheung et al. 2015). Thus, the body goes into a strategy the next joint complex up the chain and attempts to gain stability at the ankle complex. Now, let’s continue to look up the chain.
The hip and foot are a team: they both have a job to do during gait. In their pre-game huddle they discuss the motor plan and attack the loading and unloading together. So, if either the foot or the hip does not have the motor control to load and unload correctly, then your body may not be moving optimally or efficiently (Koshino et al. 2014). In many studies, athletes with chronic ankle instability demonstrated decreased muscle activity of ankle, knee, and hip musculature during common functional rehabilitative tasks (Sheng-Che et al. 2017). It has also been shown that hip and ankle coordination during walking was impaired in subjects with chronic ankle instability. So you if want your star team to play well, you need to work those feet and ankles!
Now, if you goners want to get really, really detailed, this is for you: here is an example of the chain of events that can happen in your gait, and it shows just how much one action affects another. If your right ankle rocker (dorsiflexion) is impaired, early heel departure can occur and hip extension will be limited. An alteration in right glute function can then follow. From here, the left step length (the length of measure from right heel strike through to left heel strike) could very likely be shortened. This would cause a premature load onto the left leg, and could very well force the left frontal plane to be more engaged than is desirable. This could lead to left core and hip frontal plane weakness and compensation patterns to be generated. A bit complicated, we know. Bottom line, the ankle and hip work together, and one affects the other. There is a good amount of research on this subject. So, in order to address one, we must address the other. As the Gait Guys say: “If there is impairment of hip extension motion and gluteal weakness due to insufficient ankle dorsiflexion in gait to acquire it, then prescribing corrective exercises to address things at the hip/pelvis level is layering a corrective to an adaptive response. We are nowhere near the problem.” We must address the foot and ankle!
Sensory input: Your brain’s map of your body
Can we all just take a moment to appreciate how cool it is that the connections among the cells in our brain change, adapt, and reorganize. We can rewire our brain. So, you want something to get easier? Do it more. Want to move more efficiently? Focus on your from and have intention in your movements. And what better place to start than the ground up. Let’s talk about about the sensory input we get from our feet. Sensation and movement of different parts of the body are controlled by different areas of the brain. For instance, when you move your big toe, a specific area of your brain triggers a signal that tells the muscles on your big toe to move. When you touch something with your toe, a neighboring area of your brain receives a signal about that touch sensation.
Look at your hand. Now look at your arm. Which is bigger? Your arm, right? Does that mean your arm has larger area of the brain devoted to its control? Actually, no. Sensations and movements of your hand are controlled by more of your brain than sensations and movements of your arm. This larger area allows you to make finer movements and a have better sense of touch. In this way, your brain essentially makes a map of your body. This is called the cortical homunculus. It represents how our body is perceived within the brain and how the neurons are distributed in these areas in order to create this perception. The amount of cortex devoted to any given body region is proportional to how richly innervated that region. The homunculus is split in half, with motor representation for each side of the body represented on the opposite side of the brain. So, in this map, our feet would be very big (take a look if you’re interested in this, https://www.pinterest.com/pin/393924298626461247/ ).
This is because the brain gets a lot of stimulus through the bottom of the foot. Sometimes that can be lost: we can be disconnected from our feet. How is your control of your toes? Now, we will not ask you to paint a masterpiece with your toes, but can you do a simple toe wave? Can you move them independently? Well, if not, we can help with that. And if we can challenge and work the feet, then we can essentially remap the nervous system by reorganizing the connections throughout the brain and nervous system (Wall 2017). And as we continue to work and move, and make smaller and finer distinctions between movements, then map of our body can change and become more clear.
Ok Goners, time to get started:
If we can strengthen feet and ankles in different positions and ranges of motion, then we can help to protect your body from injuries. We can wake those muscles up that have not had much work, and we can remap the system! This month we will help you work the feet and ankles. And this will in turn help you up the chain, with knee and hip function. And do you think that hip function affects back, shoulder and neck? Well of course it does. It is all connected folks! So get ready to give those old dogs some love!
-Laurel Lippard
References:
Avi Elbaz, MD ,Irina Magram-Flohr, MPT, MD,Ronen Debi, MD, Leonid Kalichman, PhD, Association Between Knee Osteoarthritis and Functional Changes in Ankle Joint and Achilles Tendon. January 2017.
Carter, J. C., Sturnick, D. R., Vacek, P. M., DeSarno, M. J., Argentieri, E. C., Slauterbeck, J. R., Johnson, R. J. and Beynnon, B. D. (2016), Relationship between geometry of the extensor mechanism of the knee and risk of anterior cruciate ligament injury. J. Orthop. Res.. doi:10.1002/jor.23366
Cheung RT, Sze LK, Mok NW, Ng GY. Intrinsic foot muscle volume in experienced runners with and without chronic plantar fasciitis. J Sci Med Sport 2015 Nov 22
Feger MA1, Donovan L2, Hart JM3, Hertel J4. Lower extremity muscle activation during functional exercises in patients with and without chronic ankle instability. Epub 2014 Jan 8.
Koshino Y1, Yamanaka M2, Ezawa Y3, Ishida T4, Kobayashi T5, Samukawa M6, Saito H6, Takeda N7. Lower limb joint motion during a cross cutting movement differs in individuals with and without chronic ankle instability. November 2014.
Péter A, Hegyi A, Finni T, Cronin NJ. In vivo fascicle behavior of the flexor hallucis longus muscle at different walking speeds. Scand J Med Sci Sports. 2017.
Sheng-Che Yen, ,Kevin K. Chui ,Marie B. Corkery ,Elizabeth A. Allen, Caitlin M. Cloonan, Hip-ankle coordination during gait in individuals with chronic ankle instability. February 2017.
Wall, Tyler. Your Brain, Neuroplasticity, & the Feldenkrais Method. 2017.
Wezenbeek E, Willems TM, Mahieu N, Van Caekenberghe I, Witvrouw E, and De Clercq D. Is Achilles tendon blood flow related to foot pronation?. Scand J Med Sci Sports. 2016.
Wink, A.E. et al. Varus thrust during walking and the risk of incident and worsening medial tibiofemoral MRI lesions: the Multicenter Osteoarthritis Study\. Osteoarthritis and Cartilage. January 2017.