Considering the Missing Link that is Trunk Instability:
Updated: Mar 27, 2020
From my experience as a Biomechanist so far, I think that there are two potential approaches to take when it comes to treating dysfunction. One method is what I refer to as the ‘Ground-up Approach’, which involves looking at the lower portion of the body i.e. the feet and lower limb. This is the type of style that a typical podiatrist would use and is one that I too am well versed with, having studied a master’s degree in Biomechanics with a main focus being on the feet and footwear, and how these can influence what goes on further up.
In the modern world we wear shoes (many of which aren’t very good for the health of the foot), and when something goes wrong with the body, whether it be within a sporting context or not, for many of us the first port of call is to make alterations to the shoes we wear. These changes can be subtle, like for example changing to a different type of running shoe that offers greater support to reduce overpronation (should overpronation be deemed to be what is causing the problem). Another approach is to use orthotics to put into your shoes to correct the misalignment.
This is all well and good and has its key advantages, as for instance, orthotics can alter the alignment of the feet, knees, and pelvis, for example. However, while this may be the case, I feel there is a blatantly obvious missing link that this approach fails to consider, and that is the role of trunk stability. Think about it – instead of just simply making changes at the foot level, what if what goes on further up can also have just as significant an effect? This is what I refer to as a ‘Top-down Approach’. This makes perfect sense when we consider the lifestyle factors of the world we live in – for instance we do far too much sitting, which just in itself can cause muscle imbalances by weakening the core, hips, glutes and hamstrings. So, let’s look at the glutes for a minute – if the Gluteus Medius muscle is too weak, then when walking and running, the individual is likely to experience ‘knock-knees’, where the knee collapses in towards the midline.
"Think about it – instead of just simply making changes at the foot level, what if what goes on further up can also have just as significant an effect?"
Now let’s go back to my overpronation example – what if the tendency of the knees to collapse inwards due to the weak glutes was also causing the feet to roll in in this way? This is a perfectly valid hypothesis given the fact that if there’s already a tendency for the knees to collapse inwards, so why would the feet (which are further down the chain) not follow suit? It isn’t just the glutes that could have an effect either, as the core and hip muscles could also contribute to this same problem in a very similar and interrelated manner. In fact, in an ideal world, I think that we would get to the point where the vast majority of us; barring any disabilities or permanent dysfunctions with the potential to alter the individual’s biomechanics, could all wear neutral running shoes and not require any extra support, because our trunk stability would provide intrinsic stability instead of relying on the shoes. This is much in the same way that you wouldn’t see a wild animal requiring orthotics to move as it’s naturally supposed to.
"you wouldn’t see a wild animal requiring orthotics to move as it’s naturally supposed to."
To conclude, simply trying to correct misalignment with orthotics would only serve as a ‘quick fix’ as it isn’t targeting the root cause while dysfunction is present further up. It also goes back to what I always say about treating the cause, and not just the symptoms. Therefore, when it comes to treating dysfunction, we need to consider the whole body, and not use a tunnel vision approach, looking at just one isolated area (e.g. the feet). Many podiatrists advertise themselves as ‘Biomechanical Podiatrists’, and while they may look at the Biomechanics of the lower limb, I don’t think that this is what Biomechanics is truly about. As practitioners we all have our specific areas of the body where we specialise, but I feel it’s time to branch out to an approach where we combine the ground-up and top-down philosophies to examine the human body as a connected structure.