- 1.FOOT CORRECTION part 1: ARCH SUPPORT
- 2.FOOT CORRECTION part 2: WEDGING
- 3.FOOT CORRECTION part 3: SHIMMING
- 4.WEDGING / SHIMMING / ARCH SUPPORT UPDATE – The Cory Davenport method of foot correction
- 5.FOOT CORRECTION METHOD: How to go about it
- 6.INTERESTING FIT PROBLEM No. 4: FOOT CORRECTION METHOD UPDATE and warning about FFMD readings
As I mentioned in the post Basic Premise I have developed a method of quantifying and restoring the prioritising by the cerebellum of the proprioceptive feedback from the feet. Without going into the nuts and bolts of the method itself, the basic picture is this:
Hundreds of millions of sensory nerves in every muscle, tendon, ligament, joint, etc named proprioceptors produce something like 1.5 million times more information about the load being experienced, position in space and relationship to gravity of each part of the body than the Central Nervous System (CNS – brain and spine) can ever process in a given second. All of this neural feedback gets through to the CNS but most of it doesn’t ‘register’ and isn’t paid much attention unless it stands out from the background ‘noise’. The situation is analogous to that of a late arrival at a large party. The latecomer (CNS) can hear a lot of noise (proprioceptive feedback) but cannot clearly make out any individual conversation (signals from a particular body part) unless a particular speaker (part of the body) raises their voice (changes the quality of stimuli) above the ‘noise’ or the latecomer moves closer to (focuses consciously on) a particular speaker and is able to listen more closely despite the distraction of the ‘background noise’.
Another analogy is this: You put on your cycling jersey and you can feel it for how long?
Then you cease to feel it because the CNS does not have the processing capacity to constantly monitor the unchanging stimuli of the jersey ‘feel’ (while attending to other matters) and bring it to conscious attention unless the quality of stimuli changes (like someone tugging at your jersey) whereupon awareness is briefly drawn to that changed stimuli (jersey tug) before it drifts off to other matters.
This is the situation we find ourselves in when riding a bike. The CNS knows the feet are there somewhere but doesn’t necessarily know the fine detail of what they are doing because the signals from the feet are drowned out by the (metaphorical) chatter. We are transferring whatever power we produce to the bike via the feet but the CNS does not have a precise awareness of what the feet are doing on the pedals for the great majority of the time, unless the rider consciously focuses on them. This will work until attention drifts, which it always does. I can demonstrate that the CNS is acutely aware of what the hips, knees and ankles are doing at all times on a bike, but the feet are akin to a proprioceptive black hole. Does this prevent anyone from riding a bike?
Absolutely not. But it does cause the rider to compensate for this lack of clarity of neural feedback. Unfortunately, compensating doesn’t solve the problem, it just increases our tendency to asymmetry because all of our patterns of compensation work by increasing our inherent tendency to favour one side over the other. This in turn heightens the chance of incurring overuse injuries. On a bike we need to be as functionally symmetrical as possible because we are locked into a largely fixed relationship with the positionally symmetrical bike. There is less likelihood of injury and a pay off in performance if we are possessed of full proprioceptive clarity from the feet while pedaling, because neuromuscular coordination is closer to optimum and functional symmetry on the bike improves consequentially.
So what to do?
The answer is to change the quality of the stimuli from the feet so it can be ‘heard’. In other words to metaphorically raise the voice of a speaker at the party or to metaphorically tug the jersey as per the examples above.
Our aim is to have the feet ‘heard’ loudly and clearly ALL of the time without our necessarily being consciously aware of the process. In general terms, there are two ways to achieve this: Correct the alignment and support of the feet, OR to correct the alignment and support of the lumbar spine. Off the bike, either will work, but on the bike there is only one choice: to correctly align and support the feet (making a positive change to the quality of the stimuli from the feet) because it is near impossible to maintain ideal lumbar spine alignment and support while riding a UCI legal bike. Doing this optimally will make sure that the CNS is constantly aware of the fine detail of what the feet are doing during every pedal stroke.
The foot is three interrelated complexes, forefoot, midfoot and rear foot. All or any of these may need correction. And correction of one part has an influence on the others. I track this kind of stuff and find that a need for forefoot correction is not rare but not common either, whereas midfoot and rear foot correction is needed by something over 95% of the cycling population. So what method(s) do I suggest?
A combination of arch support and canting of the foot is the answer. How to determine the relative degree of each?
The method that I’ve developed allows for certainty, but I’m not going to disclose proprietary info here. I will give general advice that will allow thoughtful fitters and cyclists to improve their current situation.
Firstly, start with arch support. In terms of proprioceptive clarity, arch support is fundamental. So if cleat wedges do the job from a proprioceptive point of view, why bother with arch support at all?
Because lengthy experience working out a method to quantify proprioceptive feedback from the feet tells me that if cleat or heel wedges alone are used, the vast majority will lose the initial positive proprioceptive response over a time frame of days, weeks or months unless the arch is also supported and stimulated by that support.
Here’s why: . Firstly some background; the body generates 1.5 million times more proprioceptive feedback (about the load each body part is undergoing, where each body part is in space and how each body part relates to gravity) than the cerebellum (the part of the brain heavily involved in matters of unconscious motor control) can ever process. Evolutionary forces have dictated a hierarchy of priorities that determine whether signal traffic will be prioritised for processing by the cerebellum or whether it will be ignored and treated as background noise. The two key categories of stimulus that the cerebellum prioritises are –
1. The generation of force
2. Any change in the quality of stimulus arriving from a particular area of the body.
We have evolved to walk and run which are natural activities. The basic muscle firing sequence of the legs ( extensors switch on – flexors switch off / flexors switch on – extensors switch off) is overseen by the cerebellum but not directly controlled by it. The basic on / off switching is performed by a bundle of neurons in the lumbar spine named the Central Pattern Generator (CPG). The CPG relies on force feedback from the feet for it’s informational input and altering muscle firing patterns depending on the information from the feet it receives. A primary component of that force feeback is plantar fascia tension (in simple terms arch tension) When we walk or run, foot shape and hence plantar fascia tension, is changing constantly and it is those changes which attract the attention of the CPG and cerebellum. In contrast cycling is an unnatural activity and the rider exerting force on a rigid soled cycling shoe has plantar fascia tension that changes little if at all meaning the CPG and cerebellum are dealing with lesser quality and volume of information from the feet, and tend to ‘switch off’ to that stimulus.
Using arch support of the correct level in a cycling shoe restores the proprioceptive feedback from the arches to the CPG by creating arch tension.
How much arch support does a rider need?
Use this 3-point scale: 1 = not intrusive, 2 = mildly intrusive and 3 = very intrusive. Cycling requires arch support of Level 2; mildly intrusive. That is mildly intrusive when standing, not when cycling. For the arch to be supported with foot in cycling shoes, there needs to be contact between the arch support and the arch of the foot. For some people who are not used to this, it can initially feel like there is too much support, particularly at the rear of the arch just in front of the heel. The test for this is that most people should cease to be consciously aware of the arch support somewhere between 10 minutes and several rides after the introduction of arch support. For instance, if you’ve ridden a couple of hundred kms over several rides and your arch support feels uncomfortable when riding, then the arch supports you have fitted are likely to be too high.
So mildly intrusive when standing in cycling shoes is the degree of arch support needed, providing that amount of arch support feels supportive on the bike after a week or two of regular riding.
It is unlikely that the insoles that came with your shoes will do the job, because the majority of cycling shoes have a woeful lack of arch support. Specialized deserve a positive mention for at least offering different heights of arch support insole. Nice try but their range of heights is too low (from a proprioceptive point of view) for anyone with moderately high or high arches.
Many cycling shoe manufacturers are slowly getting the idea that quality arch support is necessary, but their efforts are tentative to date, with no major shoe manufacturer offering a wide enough range of arch support heights to work ideally with the majority of riders.
Which brands of arch support insoles do I recommend? Currently, twoonly. Sof Soles Fit and G8 Performance. I don’t like the conformable, heat moldable, mass produced insoles because most riders do not get the molding process right and end up with too little or less commonly, too much arch support. The ubiquitous Superfeet are generic, a bit too generic, but work really well for those with very low but otherwise normal arches (though not flat feet). Again, if they feel ‘mildly intrusive’ when standing in them, they’re fine. If they feel ‘not intrusive’ there is not enough arch support from a proprioceptive point of view.
For the majority, the best options I’ve found are Sof Soles Fit and G8. They’re available in a wide range of sizes which between the two brands cover from size 37 – 48. G8’s are sold as a kit with five modular arch support options of differing heights. Sof Soles Fit are fixed heights that equate with the 3 highest G8 arch insert options. Of the two, both are good but the G8’s have the advantage of a wider range or arch insert heights. Both have a rigid heel cup base.
Don’t fall into the trap of thinking that you will necessarily need the same height option of arch support for each foot. It should feel the same on each side and for most this will mean the same height. Some will require a different arch height on each side..
So why support the arches at all?
For many, arch support insoles are not really supporting the arch in a mechanical sense. They are applying slight upward pressure to the plantar fascia. Pedaling a bike requires a precise and complex sequence of muscles firing in an appropriate order. Despite what you might think, this process is not performed by the cerebellum but by the CPG (Central Pattern Generator) a bundle of neurons in the lumbar spine. The cerebellum oversees the task but it is the CPG that performs the basic extensor on – flexor off / flexor on – extensor off firing sequence of the muscles of the legs. The CPG responds to force feedback, from the feet, of which arch (plantar fascia) tension is a major component, making it likely that the greater the clarity of proprioceptive feedback from the feet, the better the chance that the CPG can dictate an optimal muscle firing sequence. When we walk and run, the feet flex and change shape constantly; heel strike, toe off etc, which means plantar fascia tension changes constantly. It is this constant change in the quality of stimuli coming from the feet that attracts the attention of the CPG while walking and running. In contrast, when applying cyclical force to a rigid cycling shoe sole, plantar fascia tension changes little and as there is little or no change, the proprioceptive feedback from the plantar fascia is largely ignored. This immediately puts the rider in compensation mode, and as I said above, all compensatory responses work by increasing the difference in left and right side function.
Once arch support is introduced and used for a period, further adaptation to its use can occur in some riders. What this means is that if an arch support option feels like the desirable Level 2 when standing, but over time begins to feel that it has diminished to Level 1 on one or both feet, then it is advisable to experiment with a higher option.
If you have obvious callousing or thickening of the skin on the sole of one or both feet immediately below 2nd, 3rd or 4th MTP joints (base knuckles of the toes), this suggests that there is localised loading which can possibly cause discomfort from nerve compression while pedaling. If so, use a metatarsal pad as it will elevate and separate the MTP joints.
What if you are using the highest level of arch support, ( the orange High Arch Sof Soles Fit or the 34 mm insert in G8’s) and it isn’t enough to achieve the desirable Level 2 / Mildly Intrusive arch support?
Add a layer, or layers of gel cork bar tape as necessary under the base of the arch support module as shown in the pic of an old Esole below.
Postscript: One of the Comments below relates to flat feet. If you have true flat feet or near flat feet, again use Level 2 arch support. Don’t be concerned if you need one of the higher arch support options to achieve Level 2. Arch support is all about how the rider perceived the level of support and is NOT about “low arch equals low arch support height”. It may do, it may not.
Do you have a bike fit success story? Please go here to share.Thank you for reading, return to the Blog page here or please comment below.