<span style="font-weight: 400;">Foot Biomechanics has gone down a storm with exercise professionals when we have presented or lectured on this topic at events and conferences. In 2016, after a 1hr lecture a newly qualified podiatrist stated...</span>

<i><span style="font-weight: 400;">“Thank you, that 1 hour lecture has just made my entire podiatry degree make complete sense!”</span></i>

<span style="font-weight: 400;">As exercise professionals we really should understand a little bit more about foot function. While a very complex part of the anatomy, it is still a part of The Integrated System that we are working with, when we exercise and train our clients. </span>

<span style="font-weight: 400;">So let’s break it down to the simplest level...</span>

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<h2><em><b>What do we, as exercise professionals, need to know about foot function and exercise that can contribute to helping our clients movement ability?</b></em></h2>
<h3>Foot Function</h3>
<span style="font-weight: 400;">Firstly once we understand </span><b>pronation</b><span style="font-weight: 400;"> and </span><b>supination</b><span style="font-weight: 400;"> the rest is relatively easy. These 2 actions are </span><b>‘triplanar’</b><span style="font-weight: 400;"> meaning there are 3 components to 1 motion. (Donatelli.R, ‘</span><i><span style="font-weight: 400;">The Biomechanics of the Foot &amp; Ankle</span></i><span style="font-weight: 400;">’ 1980) </span>
<h4><span style="color: #33cccc;"><b>PRONATION</b></span></h4>
<span style="font-weight: 400;">- Dorsiflexion - Eversion - Abduction = ‘unlocks’ MidTarsalJoint (MTJ), flatter, longer, wider, flexible, mobile foot which enables </span><b>shock absorption</b>
<h4><span style="color: #33cccc;"><b>SUPINATION</b></span></h4>
<b>- </b><span style="font-weight: 400;">Plantarflexion - Inversion - Adduction = ‘Locks’ MidTarsalJoint (MTJ), higher, shorter, narrower, stiff, rigid foot which enables a </span><b>rigid foot to ‘toe off’</b><span style="font-weight: 400;"> and therefore propels you forwards during the gait cycle. </span>

<span style="font-weight: 400;">So during the gait cycle the foot SHOULD be able to achieve both pronation and supination. However, we also need them to occur at the appropriate phase of the cycle, in order for it to be </span><span style="font-weight: 400;">biomechanically efficient.</span>

<span style="font-weight: 400;">In this image you can see the gait cycle broken down into its stages.</span>

<img class="aligncenter wp-image-1784" src="https://www.biomechanicseducation.com/wp-content/uploads/2017/04/Screen-Shot-2017-04-18-at-10.55.17-1024x642.png" alt="" width="600" height="376" />
<h4><span style="font-weight: 400; color: #33cccc;">HS OR HEEL STRIKE</span></h4>
<span style="font-weight: 400;">When the heel first comes into contact with the floor and so the foot is pronating to absorb the force or shock. </span>
<h4><span style="font-weight: 400; color: #33cccc;">FFL OR FOREFOOT LANDING</span></h4>
<span style="font-weight: 400;">When the forefoot then lands coming into contact with the floor and so is still pronating.</span>
<h4><span style="font-weight: 400; color: #33cccc;">MIDSTANCE</span></h4>
<span style="font-weight: 400;">When the weight of the body starts to shift over the ankle. This is when the foot transitions from pronation to supination via the ‘windlass mechanism’ (see below), that initiates tension in the plantar fascia taught.</span>
<h4><span style="font-weight: 400; color: #33cccc;">HL OR HEEL LIFT</span></h4>
<span style="font-weight: 400;">When the foot starts to become more rigid. The more the big toe (also known as the Halux or 1st metatarsal) extends, the more the plantar fascia tension increases. This creates a more rigid arch for the propulsion phase of supination.</span>
<h4><span style="font-weight: 400; color: #33cccc;">TO OR TOE OFF</span></h4>
<span style="font-weight: 400;">The extension of the big toe completes the cycle, eventually lifting to the swing phase.</span>
<h3>The Problem</h3>
<span style="font-weight: 400;">One of the most common problems identified is ‘</span><i><span style="font-weight: 400;">over</span></i><span style="font-weight: 400;"> pronation’ and so prescriptions are given to </span><i><span style="font-weight: 400;">reduce</span></i><span style="font-weight: 400;"> the degree of pronation ie; shoes with a supporting arch. This could be the right thing to do if symptoms are occurring.</span>

<span style="font-weight: 400;">However we must be mindful of the fact that our feet </span><i><span style="font-weight: 400;">need</span></i><span style="font-weight: 400;"> to pronate. So considering the gait cycle above, it can be more helpful to consider this foot type as a </span><i><span style="font-weight: 400;">late</span></i><span style="font-weight: 400;"> supinator. In other words, the foot doesn't ‘lock’ in time to re-supinate at the midstance phase. This means the foot is still pronating and unlocked leaving the foot in a lax position for propulsion. </span>

<strong>Now there are many things that can influence these triplanar motions as you can imagine:</strong>

<span style="font-weight: 400;">1) Footwear</span>

2) Impact force and frequency

<span style="font-weight: 400;">3) Descending Biomechanical issues (i.e. pelvic dysfunction)</span>

<span style="font-weight: 400;">4) Previous injury</span>

<span style="font-weight: 400;">5) Genetics</span>

<span style="font-weight: 400;">6) Ground surfaces</span>

<span style="font-weight: 400;">7) </span><span style="font-weight: 400;">Job type</span>

<span style="font-weight: 400;">8) Sports</span>

<span style="font-weight: 400;">And so on...</span>

<span style="font-weight: 400;">If we look at the potential problems, it can allow us to understand what we can and can’t influence, or do.</span>

<span style="font-weight: 400;">Orthotic and footwear prescriptions should always be left to the professionals trained to deal with these, like podiatrists for example. However, descending biomechanical problems are certainly within the remit of a PT or exercise professional.</span>

<a href="https://www.biomechanicseducation.com/custom-fit-insoles-damaging-workout-performance/" target="_blank" rel="noopener noreferrer">Check out my blog about my visit to Premier Podiatry by clicking here.</a>

<span style="font-weight: 400;">As personal trainers we could conduct a </span><span style="font-weight: 400;">series</span><span style="font-weight: 400;"> of foot screens or use a foot posture index, to get a good idea of whether our client has a propensity for pronation or supination or in fact has a neutral foot. Once we’ve concluded the outcome that most suits our client, we can start to plan the right exercises to prescribe, to either contribute to better foot function or as pre-orthotic conditioning process (see below). This allows us to communicate much more effectively with podiatrists when we need to make a referral.</span>

<span style="font-weight: 400;">We would </span><i><span style="font-weight: 400;">ALWAYS </span></i><span style="font-weight: 400;">advise performing more than one screen, due to the complex nature of the movement planes in the foot and ankle, as it can commonly occur that your client may present as having a propensity for pronation in one screen and a propensity for supination in another.</span>
<h3>The Solution</h3>
<span style="font-weight: 400;">What CAN WE do?</span>

<span style="font-weight: 400;">The first thing is to get an understanding of foot anatomy and function, in relation to pronation and supination. Visually someone might look like a pronator yet they are structurally a supinator. If they have a fat pad on the arch for example, it may give the impression of a low arch or pronated foot. So we must never assume anything and certainly not when we don't need to!</span>

<span style="font-weight: 400;">This screen is just one example of a foot screen and how simple they can be. This particular screen is simply to identify if the foot has the </span><i><span style="font-weight: 400;">capacity </span></i><span style="font-weight: 400;">to re-supinate.</span>
<h3>Jacks test (ascending influencer)</h3>
<img class="aligncenter wp-image-1785" src="https://www.biomechanicseducation.com/wp-content/uploads/2017/04/IMG_4580-1024x768.jpg" alt="" width="600" height="450" />
<h3>Why?</h3>
<span style="font-weight: 400;">The Jack’s test assesses the force required to activate the windlass mechanism. This test assesses the tension in the plantar fascia associated with Heel Lift, Toe Off and Propulsion to identify the foot's capacity to supinate. </span>

<span style="font-weight: 400;">The way in which the terminal strands of the plantar fascia wind around the metatarsal heads, has been called the Windlass Mechanism (Hicks, 1954). What is fascinating is that people vary greatly in the force required to dorsiflex the big toe, to activate this Windlass Mechanism. It is believed that orthoses that decrease this force, reducing the strain in the Plantar Fascia and thus improving the efficiency of gait.</span>
<h3>The Windlass Mechanism</h3>
<span style="font-weight: 400;">The term ‘Windlass Mechanism’ is used to describe the function of the plantar fascia. </span><span style="font-weight: 400;">The Jack’s test can be used to assess the effect of devices on the establishment of the Windlass Mechanism.</span>

<span style="font-weight: 400;">The plantar fascia is drawn tightly around the big toe joint, so as the big toe moves upwards (dorsiflexes), it develops tension within it. This tension pulls the joints of the foot tightly together, and converts the foot to a rigid structure, in preparation for the forward thrust of propulsion. This increased foot rigidity is reflected by the increase in arch height, as the fore-foot is drawn down and closer to the rear-foot. This is also very important in relation to shoe design.</span>
<h3>What?</h3>
<span style="font-weight: 400;">You’ll be using the 1</span><span style="font-weight: 400;">st</span><span style="font-weight: 400;"> metatarsal (big toe) as a lever in the sagittal plane </span>
<h3>How?</h3>
<span style="font-weight: 400;">You manually dorsiflex the big toe and estimate the force required. Kneeling in front of your client, who should be standing naturally, place hands flat on either side of their foot. Slide both your thumbs underneath their big toe and pressing the fingers into the floor for support you push the big toe upwards sagittally and as far as it will go. Look to see if the inside of the foot lifts into an arch.</span>

<span style="font-weight: 400;">This effort or resistance it takes to do this can be graded from 1 to 5. </span>

<span style="font-weight: 400;">1= no effort at all to push the toe up</span>

<span style="font-weight: 400;">5= toe impossible to lift and engage any arch or supination </span>

<span style="font-weight: 400;">The tension in the plantar fascia increases as the big toe is dorsiflexed and the subtalar joint must supinate to raise the arch.</span>

<span style="font-weight: 400;">A score of 2-3 is a pass, anything higher or lower is a fail.</span>

4-5 is difficult to lift and therefore means that the subtalar joint has limited capacity to re-supinate the STJ and so they are more likely to be a pronator.

0-1 is really easy to lift and therefore means the subtalar joint easily supinates and the client is less likely to be a pronator.
<h3>Ok Now What?</h3>
Well we must still be mindful of appropriate referral and duty of care if we are ever unsure or particularly if clients are symptomatic. However an example of something safe we could do is POC-ing.
<h3>POC-ing</h3>
POC-ing or pre-orthotic conditioning is simply a series of exercises that prepare the lower limb, ankle and foot for orthotics. Often the leg is unprepared for changes to the new position under foot. This can sometimes result in discomfort or achy muscles (DOMS) even though the orthotic is correct for that individual. They may simply need some ‘preparation’ for their new position.

<span style="font-weight: 400;">(Note: Likewise sometimes a wrong orthotic can alleviate pain even though a prescription might be inaccurate, as the simple act of changing the load going through the joints could alleviate loads to a different place.)</span>
<h4><span style="color: #33cccc;"><strong>EXAMPLE;</strong></span></h4>
<span style="font-weight: 400;">If you feel your client lacks the capacity to supinate have them sit down and place a resistance band around the inside of their foot, like the image below. Tie or hold the band to give the resistance. </span>

<span style="font-weight: 400;">Now encourage them to turn the foot inwards against the resistance band for 15 reps and 3 sets or as you see fit.</span>

<img class="aligncenter wp-image-1786" src="https://www.biomechanicseducation.com/wp-content/uploads/2017/04/IMG_8821-1024x1024.jpg" alt="" width="600" height="600" />
<h3>Final note;</h3>
<span style="font-weight: 400;">Always use inter-professional relationships for optimum duty of care.</span>
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