Minimal, cushioning, barefoot? Maybe it doesn’t matter.
The last 10 years have seen the barefoot and minimalist running revolution come and maybe even go, however it is a question that I get daily from patients. What kind of shoes should I wear? And how should I run to minimise the impact on the ground, should it be a heel strike, midfoot or something in between?
The study that pushed people to question this was the work by Lieberman in 2010 Nature paper that suggested that impact forces were lower with barefoot running compared to wearing shoes. This seemed to spark the revolution, however consistently since that time researchers and clinicians alike have been looking at the multitude of other factors that go into what makes up running ground impact forces, how technique adjusts with different footwear and the overall effect of running conditions.
More recent work by Udofa et al 2019 using the techniques developed by Ken Clark and Peter Weyand starts to look at the effect of different footwear and how impact forces are created and also adjusted by different footwear. Interestingly loading is similar in each condition, the main difference is that people will alter the angle or point of contact with the ground if they are wearing shoes or not. So typically wearing shoes the runners are happy to put their heel onto the ground and have a higher loading rate, which is the speed at which the force is created (this sounds bad but is probably not, I will explain shortly) whereas the barefoot runners will place the midfoot onto the ground and absorb the forces through the calf and achilles to reduce the loading rate that the impact force creates. The interpretation by a number of researchers and clinicians is often that this reduction in loading rate is a good thing, the rationale being less is better. But our friends from physics will tell us that the first law of thermodynamics is that energy is neither created or destroyed, it is just transferred.
Why is this important?
The energy or forces that occur when landing do not disappear based on where you put your foot down onto the ground or what shoes you are wearing. They just transfer to other areas of the body. This means that you can try and manipulate the landing position of the foot but you will always have to deal with the forces somewhere. In the barefoot example, your calf and achilles absorb the forces, so if you are getting knee pain due to landing on your heel on the ground, the solution of running barefoot or landing through the midfoot is robbing Peter to pay Paul. You may get less knee pain, however you may develop achilles or calf problems due to the compensation that occurs on landing.
So what is the solution?
Particularly if you are not sprinting (distance running), the best solution is to adopt a running pattern that creates an even distribution of forces through the foot, ankle, knee and hip. The best way to do this is to land on a full foot strike (greatest base of support) and keep the landing under the hip as much as possible (close to the center of mass of your body). This allows you to ustilise each joint and surrounding muscle and connective tissue to their greatest capacity and allows you to use the biomechanical advantages (levers etc) to distribute forces evenly, as we said the forces will always be there, you get to choose which joints and muscles need to deal with them. Now you can also manipulate step length and frequency, which we will not get into now, however particularly increasing step rate will allow you to land under your centre of mass easier and thus assist with this force distribution.
So does it matter whether you wear shoes or not? Probably not, the best solution is to learn to run in a way that maximises your body’s capabilities to distribute forces and push you forward.