Heel counters: whats all the fuss about?ASICS

Heel counters: what’ s all the fuss about?

By Dr. Chris Bishop PhD

Shoe design is a difficult task.

With the common goal to reduce mass of a shoe, how can designers include all of the technology they desire without the shoe feeling like a brick? The argument is often that shoes have been over engineered, and it is often questioned what technical design features can be removed without compromising the function, structure and support that a technical running shoe provides. One of the main design features in the spot light is the heel counter.

Do we need it…at least in its rigid form? If yes, is it internal or external?

Walk into most shoe shops and you will get the standard line that a firm heel counter will support the foot during gait. But really, is this true? Do we know this? What is its role? Does it control foot pronation? Does it aid in stability as the foot is loaded? Does it simple provide structure and shape to the shoe? Despite the often quoted conceptions about what a heel counter actually does, the reality is that little is known from a scientific point of view.

Firstly lets look at its intended role and then we can explore the supporting science. The shape (construction) of a heel counter can have a significant impact the overall fit and feel of the shoe. We know that heel fit is a really important consideration in the overall comfort of a shoe. Surprisingly, differences in the shape, degree of padding, depth, how well the shape of the heel matches the shape of the back of the heel counter can be overlooked, particularly in a retail environment. It is then sometimes overcome by different lacing techniques, when really the 'openess' or design of the heel counter doesn't match the individuals heel shape. This can cause significant issues with internal heel wear or rubbing on the posterior aspect of the calcaneus (especially if a haglunds deformity is present). The suggestion that an external heel counter is 'better' because it allow for the natural movement of the foot during midsole compression and reduce wear is also largely unsubstantiated and simply a belief. However the greatest misconception is that it somehow ‘guides’ the heel as the foot touches the ground and helps 'control' the heel from excessively pronating.

When we delve through the literature and look at the science underpinning rearfoot shoe design, apart from the work of Nigg and Butler in the late 1980’s, minimal work has been done substantiating the presence of a heel counter in the modern athletic shoe. This doesn’t say that many of the shoe companies haven’t done their own R&D and simply haven’t published their work which I’m sure they have. But lets look at some of the findings out there with respect to motion control, fit and variability in response:

In 2000, the late Alex Stacoff and co-authors compared hindfoot biomechanics during running both barefoot and in shoes. There findings contrast the previous findings in the literature that showed substantial and significant reduction of hindfoot eversion, identifying that the differences in calcaneal eversion between barefoot running and running with normal shoes were small and not systematic. Given these authors used more accurate methods by attaching markers directly to the bone rather than on the skin, it is likely that previous studies identifying a reduction in hindfoot eversion were measuring the movement of the shoe and/or skin, and not the true movement of the underlying bone. This indicates no motion-control benefits were identified.

In 2007, Irene Davis and co-workers published their findings on the contribution of a heel counter to internal stresses of the heel pad during static standing. When comparing the results of a finite element model of the heel inside the shoe with and without a heel counter, the heel counter provided

inwards directed pressure on the skin which counteracted the internal pressures within the fat pad pushing outwards when loaded. This reduces stress in the heel pad. Despite the research occurring in static standing and isolated to one subject, the insights provided in this study have plenty of implications for running - a well-fitted heel counter may actually be an effective reducer of heel pad stress…think of all those runners with heel pain, or maybe we have an answer to the increased magnitude of vertical force when heel striking? Regardless of whether you understand the methods used in this paper, it indicates that an appropriately fitting shoe is extremely important in the overall effect of the shoe.

At the 2013 SMA conference in Phuket, I presented data from our lab at the University of South Australia. Using our in-shoe foot model, and based on the existing literature, we thought that during running, shoes would not reduce either the amount of hindfoot eversion, nor the velocity of the movement. Based on data from 18 runners, very small and non significant differences were identified between the barefoot and shoe conditions. However, what was interesting was when we broke down our analysis to look at the variability of how each person responded to the shoe condition. Nine of the runners actually everted more, and nine runners everted less, with the net effect of the increase in eversion balanced by the decrease in eversion to result in no identified difference at all. This indicates based on pooled or average data, researchers can be quick to jump to conclusions about the net effect of a design feature, when in reality, individuals are likely to respond to different things in different ways. Does it control motion –well yes and no and it depends on the individual. However it shouldn’t be classified as a motion control feature of the shoe. Rather a heel counter should be viewed as a design feature that improves the fit of the shoe around the heel of the foot, and in a properly fitted shoe, the runner’s heel should feel supported (and not slip) the whole time the foot is in contact with the ground. It should be a smooth ride. And look, if we can get the same fit benefits from an external shoe counter and drop 3-4 grams from the shoe, then this is going to be a great result as well!

Is this saying that a shoe without a heel counter is also no good…no not at all. Every shoe has some structure. And some people may like this. There will be a slight reduction of mass, less issues with material friction yet may also result in shoe structure compensations.

So is it internal, external or none at all? How do you choose the right counter or what should you recommend patients?

Go with what the individual feels is ideal, what they feel fits best and what they prefer. The individual perception of what is most ideal for them is highly likely going to end up being the most comfortable.

So in my opinion, what is the fuss about the heel counter and is it required…simply yes. I think it improves comfort and fit of a shoe, and retailers need to be appropriately skilled in assessing rearfoot width and fit, not just whether there is enough room in the forefoot across the toes. Appropriately fitting shoes in the rearfoot will reduce heel slippage which is a common complaint amongst runners, resulting in a reduction in the amount of blisters and the break down of the shoe upper material behind the heel.