How do you choose the running shoes you buy? Do you get advice from a professional? What criteria do they use to select the ‘best’ shoe for you? Although the tide is slowly changing, there are still a lot of myths circulating out there regarding how to select appropriate running shoes, ranging from ‘not a lot of evidence’ to ‘simply not true’. Despite what you may have read or been told, research shows that there really isn’t a hard-and-fast way of telling what type of running shoe will be best at keeping injury away.

LOW ARCHES AND OVERPRONATION

Although popular, the traditional method of selecting running shoes according to arch type (high/neutral/low) is not actually based on any scientific evidence. In fact, research suggests that choosing your footwear in this way provides about the same chance of injury prevention as choosing a shoe at random. And sometimes it can make things worse!

WHY IS ‘ARCH TYPE’ USED?

In a nutshell, because it’s simple. It allows all runners to be placed into one of three categories for which each has a shoe type solution. The idea is believed to have come from a military study on interpreting enemy footprints by seeing what marks they left in the snow. This developed into the ‘wet foot test’, i.e. the imprint that your wet foot leaves on the ground telling us whether you have high, neutral or low arches, and that those with high arches need a more cushioned shoe, those with low arches a motion control shoe, and those of us who are in the middle and ‘normal’ can enjoy a ‘neutral’ shoe. A neat, tidy idea but sadly no evidence to support it.

OVERPRONATION

Though the wet foot test is generally no longer used as a way of recommending shoes, what happens at arch level continues to form the basis of most running shoe selection and recommendation. Many injured runners tell me they are ‘pronators’ as if that was some kind of problem. Pronation is a natural movement that occurs when we walk, run and jump. It refers to a series of joint movements at foot level that allow us to absorb impact (decelerate) and prepare for the next push off (accelerate). One of the most noticeable is the dropping of the arch on the inside of the foot (the medial longitudinal arch). But, as is so often the case with human physiology, how much the arch drops can vary a lot according to the individual. Somehow, the shoe industry decided that everybody should be pronating a certain amount, and if you fell outside the ideal ‘neutral’ position you were opening yourself to injury. But there is no robust evidence to suggest an optimum amount of pronation. You only have to look at some of the elites to realise that ‘overpronation’ is alive and well and setting world records. Running legend Haile Gebrselassie is a great example.

HOW DO WE CHOOSE RUNNING SHOES?

So, despite the erroneous explanations, we do know that different types of running shoes help some runners out, some of the time. We just don’t know how or why. Researchers are working hard to discover why some runners with, for example, low arches benefit from motion control shoes but others get even more injured. In the meantime, it’s a case of using trial and error and going by what feels comfortable. Though this sounds like a very unscientific way of choosing running shoes, research has linked comfort with reduced injury, so there is in fact more evidence for using comfort than anything else.

DEGREE OF CUSHIONING

It’s natural to feel that repeated landing on a hard surface like pavement, track or treadmill demands some form of cushioning. This is why running shoes traditionally have a built-up heel. And yet, studies show that the moment when the highest amount of load travels through our leg is not at initial contact (when many of us at lower speeds land on the heel) but actually at midstance when your bodyweight is over your foot, or at toe off when your back foot leaves the ground. In other words, for many runners reducing impact is probably more of a question of improving running form rather than wearing built up heels. There is also growing evidence that the body has its own very clever way of dealing with impact and different running surfaces. Every step you take, internal receptors are feeding back information to the brain so that it can make necessary adjustments to minimise potential harm. To deal with changes in impact forces, it has options like modifying joint stiffness, changing the way the foot strikes the ground, and also via a concept known as ‘muscle tuning’. Based on information received visually and from the previous foot strike, the body adjusts how strongly the muscles in your leg contract before the foot hits the ground again. Imagine jumping on a trampoline – your legs naturally stiffen in preparation for the soft landing. Now imagine yourself jumping onto concrete – your legs naturally become less stiff in preparation for the hard landing.

LEG STIFFNESS & INJURY

If wearing more cushioned shoes equates to more stiffness in the legs and less cushioned shoes means less stiffness, how does this relate to injury risk? Well, as is so often the case in running injury research, results conflict. Some studies (Dr. Irene Davis) link increased leg stiffness with issues like plantar fasciitis and tibia stress fractures. But other studies (Dr. Benno Nigg) find that overall injury rates are slightly lower among runners with increased leg stiffness. The studies do mean that leg stiffness could be an important factor to consider with regards to certain injuries. If your body has suffered plantar fasciitis and tibia stress fractures, then one of the solutions worth considering (among the many other potential modifications) would be to try and wear a less cushioned shoe. By landing on a harder surface, your body will automatically reduce leg stiffness, which in theory could reduce your susceptibility to plantar fasciitis and tibia stress fractures. At this stage, it is all theory, and we draw particular attention to the word ‘try’. As always, introduce any changes to your habitual routine very slowly and gradually. Running shoes are no exception to this rule. Give your body a chance to tell you how it feels about the change before you do any harm to yourself.

GO FORTH AND TRY OUT DIFFERENT SHOES

There may not be any hard-and-fast model for selecting a running shoe, but try not to despair. See it as liberation as opposed to a hindrance. One of the best things to emerge from the downfall of the traditional running shoe selection model is that we today have a far larger variety of designs of running shoe to choose from. Having seen that heavy cushioning is not necessarily helpful to everybody, you should now hopefully be more confident to test some lighter trainers. The secret is experimenting to see what feels comfortable for you. And bear in mind that a trainer that suits you for one distance, terrain or speed may not work as well for another.

TRY SLIGHTLY LESS HEEL

The technical term for this is less of a ‘drop’ (the difference in height between the heel and the forefoot). Traditional running shoes have a heel-toe drop of about 12mm. Vibram Fivefingers have pretty much a drop of 0mm. Choosing a shoe that takes you straight from 12mm to 0mm is not a good idea. There is a wide range of 6-10mm trainers on the market which will allow you to experiment more gently.

MORE THAN ONE PAIR

If the majority of running related injuries are down to repetitive overload, one way to vary that load is to vary the type of trainer you wear during the week (as well as the type of terrain). Even a very slight change in trainer style will change the impact forces your legs have to deal with.

LISTEN TO YOUR BODY

If comfort is the best system we have of seeing if a particular running shoe suits our body, running on a shoe that niggles is not a good idea. Many of the running injuries I see in clinic are linked to a runner buying a new pair of trainers and failing to break them in gently. Even a new version of the same trainer can be slightly different. Respect the fact that your body will often need time to fully accept it.

F.I.T. BEFORE FOOTWEAR

At the end of the day, you can get injured in pretty much any shoe. Frequency, Intensity and Time of running play a far more important role in injury prevention than what you put on your feet. Running form can also play an important role, which is why gait analysis needs to be more about looking at running technique rather than a way of prescribing running shoes.

 

Written by Matt Phillips of Studio57clinic & StrideUK.
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