Running footwear is a multi billion pound industry and the choices available to the runner are mesmerising. The science behind the marketing campaigns can be hard to find but there are some features inherent to running footwear that need consideration when making your purchase of your shiny new trainers and this guide is aimed at making your final decision a little more specific to you.
Before we get to the key points is worthwhile considering other factors outside of the trainer selection that are essential.
Running trainers in isolation will rarely provide the solution to an injury once its occurred but can minimise some of the factors that could lead to the development of an injury.
Training errors such as consecutive running days and a high running volume are the biggest risk factors in running injury; you can either over-train or under-recover!
Gradual increases in mileage are vital in allowing the body to adapt to the increasing mechanical stresses placed upon it.
Adding in a specific strength and conditioning programme for your legs is a key way to build up robustness.
The choice of your runner will be based on 2 main factors (other than cosmetics!):
The running trainer purchase by itself is not going to cut your 10km time to a sub 40 minute session from 50 minutes.
To improve performance you need to be able to gradually increase your training load and allow the body to adapt to the mechanical demands and the running shoe can be one variable in minimising injury risk.
When looking at the wealth of running footwear options I would recommend considering the following components in running shoe design:
It sounds basic but one of the key features in running shoe selection is the fit. This is where the trip to the running shop in the first instance is important. The last fitting or upper fit needs to be relatively snug, a running shoe that is too big will allow the foot to shear (slide) in the trainer which will increase the risk of blistering on the foot and, in a similar fashion, a trainer that is too small will add compression (squeezing) force on the foot and increase the risk of bone injury.
Those dreaded toenail problems with bleeding or bruising underneath the nail plate can also be caused by poor fit so its worthwhile seeking advice from a health care professional with a special interest in foot problems if this is occurring.
Fit and therefore comfort is a big part of running footwear selection, if you have a choice between two trainers and one feels more comfortable than the other (assuming the other variables below are similar) then go with the comfortable one.
The running shoe industry has been through a culture shift over the last few years with an explosion in minimalism.
Lack of ankle joint movement in an upward direction (dorsiflexion) is a risk factor for injury. It is relatively simple to screen for with a lunge test (bending knee over the foot and measuring the angle of the shin bone) and this provides useful information for choosing a shoe with an appropriate heel height or drop.
It is recommended that the Lunge test is performed in the presence of a health care professional that is familiar with this test as you would be surprised how people unknowingly cheat!
The heel height, referred to as pitch or drop in the footwear world can range from 0 – 14 (for the purposes of illustration) and is measured in mm.
As a rule of thumb the stiffer the ankle joint (closer to the wall your toe is on the Lunge test) the more relevant a running trainer with a higher heel drop.
Footwear designs have changed over the last few years with shoe companies exploring the concept of minimalism.
This essentially means that the heel drop profile on the trainer is reduced to anything from 0mm to 4mm and the overall stack height of the trainer (sole unit thickness) is also reduced, considerably sometimes.
I use ankle flexibility or lack of, as a guide to the heel pitch profile of a running shoe choice and is one metric that I measure in my clinical assessment.
There is no straight forward answer here but any material that absorbs impact force that sits between you and the floor has to be a good thing right?
The industry is constantly looking at these type of materials and Nike have developed their Lunarlon range and Adidas their Boost midsole as examples.
The main question is how much is too much as this could add to instability, picture landing on a pillow! and what is the minimum required. This is one area that needs consideration and is related to factors such as your biomechanics and body weight and would benefit from advice from a specialist.
In my experience there are very few runners out there that fit the minimalist running shoe model and these would tend to more toward the elite end of the spectrum and / or low body mass.
For those of us who run to a moderate or reasonable level then we would need to consider an element of cushioning in the midsole along with the other factors such as heel drop and fit.
Cushioning is not our enemy in the running world, reducing impact forces is critical in moderating the forces we generate when we run.
Too much cushioning brings other issues so understanding how you move and how your body deals with impact forces is crucial in choosing the footwear range that reflects you own unique risk factors.
As simple as it sounds its important to consider the type of surface you run on and the compatibility of the outsole.
There are key differences in the type of outsole for road trainers and all terrain or off road trainers.
Those of you that have run on a surface with the wrong outsole may recall sliding around and the risk of soft tissue injury is increased.
Remember its the outsole that is different, invariably the midsole factors should be consistent from the road version to the all terrain version.
Welcome to the contentious world of motion control!
Bottom line is that footwear can be overly engineered but there are some design features that contribute to reducing the mechanical forces on the foot and lower limb and therefore reduce injury risk.
The concept of pronation bad is oversimplifying the foot contribution to injury risk but it does highlight how foot position can be a factor in the spectrum of mechanical forces that will lead to lower limb symptoms.
There is no question that in my clinical practice foot position is a component part of the runners injury risk factor.
Landing on an overly cushioned sole unit offers very little in terms of any meaningful push back potential. Looking at your landing angles can provide an insight into the stability features that may mitigate some of the forces that act on the foot / ankle / leg during running.
Gait analysis provides that feedback mechanism, essentially you can see what your clinician sees when your running gait is assessed and video playback is a key tool in the visual feedback process.
If you run on a regular basis and have any niggling joint or soft tissue problems or you are looking to make a new investment in running footwear then it might be worth looking at a foot and movement screen to be more informed about your mechanical make up.
In a similar fashion if you are new to running or are considering adding running into your exercise régime then its a great time to look at your structural risk factors for injury and minimise these to progress in your running program.
Technology and cheating!
The media is full of how Nike have (allegedly) cheated their way to world record times with their modified Vapour Fly and next generation sole units.
The sole unit on the Nike is not a new concept, New Balance ventured down this path in the 80’s with limited success and an (alleged) suspicion that it was contributing to an increased injury risk in the lower limb.
Bizarrely we have been modifying footwear historically for decades with sole unit stiffeners and rocker soles to manage many of our orthopaedic cases where big toe joints or ankle joints are limited post surgery or post trauma.
In my opinion what Nike have achieved is an amazing design of combining stiffness with cushioning and refined the external forefoot curve to achieve potential performance gains.
Reducing big toe joint bending moments in theory creates a mechanical advantage (this blog is not about this discussion so please read up on the facts about the project).
The sole unit profile though is a fantastic addition to the armoury when dealing with runners or non runners with forefoot pain, so conditions like stress fracture / sesamoid pain / neuroma / post surgical forefoot patients benefit from this concept.
The stiff rocker concept is not unique to Nike, Asics do a couple of trainers with this concept, as do Hoka with their Carbon X. Its likely an evolving space given the alleged performance gains so we may well see other companies following this pattern.
It is essential to note though that this trainer is not the panacea for all runners to improve performance or to deal with all types of lower limb injury.
For certain people it is a great shoe option, for others its trading risk factors.
The evidence behind specific running footwear is limited and one type (neutral / stability / motion control) will not suit all.
Every runner is case study one and and one shoe type is not going to suit everybody.
The key to shoe choice is based on a number of key variables described in this article and if you want to know more about your mechanical make up and its interaction with running footwear choice then I would suggest making an appointment with a clinician with a specific interest and experience in this area.