Gait Analysis for Runners: simplifying the jargon

Walking into a running shop to be greeted by a wall of trainers can be intimidating to say the least. Well, that was my experience last week when I finally decided it was time to replace my Asics GT2000’s. I mean, where do you even start? By brand? Stability? Colour?? When it comes to choosing the right running shoes, it’s a minefield. So, I’m going to do my best to use my physio experience in an attempt to simplify a world of overpronation, midstance and toe boxes!

Let’s start with the gait cycle. Which, by the way, is just the technical term to describe the way we walk or run. There are two main parts:

Stance phase

The period during which the foot is in contact with the ground

Swing phase

The way the leg swings through BEFORE the foot makes contact with the ground again

In terms of considering running shoes, the swing phase is largely irrelevant as the foot isn’t in contact with the ground so I’m going to concentrate here, on the all important stance phase.

The stance phase is commonly split into three separate stages.

Initial contact

Imagine you’re running along. Your left foot is out in front of you about to touch the ground. The exact moment it does, a mere fraction of a second, is called ‘initial contact’.

What should happen?

The initial point of contact will vary depending on your speed and individual biomechanics. When walking for example, you should strike the floor with your heel first.  Increase the pace to a run, and the point of contact usually moves further towards the middle of the foot. High level sprinters will even land straight onto the ball, known as toe striking. Something you can really notice on this slow motion footage of Usain Bolt.

With each of these three options, the strike point should be with the foot in a slightly supinated position. This basically just means that the sole of the foot is turned ever so slightly inwards towards the other foot so that as it hits the floor, the contact point is on the outside of the foot. You can check this by looking at some shoes you’ve owned for a while. Towards the heel, the outside of the shoe should show more wear than the inside. You can see in the photo above, my foot is tilted so that the outside of my heel is going to contact the floor first (this is supination).

Wherever you land on your foot, initial contact is the ‘cushioning phase’. It triggers a chain reaction through the muscles in your leg that should help to absorb the landing.

Common problems

A heavy heel strike in runners is thought to be less efficient. It is often a sign of landing with your foot too far out in front of you, meaning that it acts like a brake rather than the pre-loading of a spring. In the running world this is called ‘over striding’.  As a result, the foot stays in contact with the floor for far longer than with a mid foot strike, as your body weight has to move over the top of it before you can push off again. Technically this is far less efficient, especially when multiplies by the tens of thousands of steps taken during a marathon.

The bigger problem though, is that it also seems to be closely linked with certain injuries. In particular conditions like shin splints. This may well be because the muscles in the lower limb are less able to cushion your landing in this position and so the forces are transferred directly through the other structures in your legs, such as your tibia (shin bone).

The ‘fix’

Try to concentrate on increasing your cadence (the number of times your foot hits the floor each minute). I find counting helps with this, or trying to match your foot turnover to the beat of a faster paced song. You are aiming to land almost directly on top of your foot. If you can see it when you look down, it’s probably still too far in front. Start by concentrating on this during small sections of a short run and build up gradually. The more you practise, the more it will become second nature.

As a physio, I found that this technique was preferable to trying to force a landing further towards the front of the foot. If this doesn’t come naturally, which it doesn’t for most runners, then it can often lead to a whole host of other problems, like achilles tendon issues.

Shoe recommendations:

Runners who heel strike usually don’t do well in minimalistic running shoes. Aim for something with more cushioning that will help with the shock absorption. Heel strikers also tend to prefer a bigger heel drop (the difference in height between the front and back of the shoe), where as mid-foot strikers will feel like this gradient gets in the way and should opt for a flatter shoe.

Remember: Most people with shin splints are heel strikers, but not all heel strikers get shin splints! i.e. if it aint broke, don’t fix it. Plenty of people heel strike with no drama. If however, you’ve had problems with shin splints or other over use injuries, then this may well be something worth looking at.

Midstance

From initial contact, the rest of the foot flattens to the ground. This flat foot position is called mid-stance. The main aim here is for the foot to provide a stable platform for your body weight to pass over. Because your other foot is now in swing phase, your entire body weight is on the one leg. This is why it is particularly susceptible to injury at this point.

Think of mid-stance a bit like pressing down on a spring. You are creating potential energy ready to release it in the next phase.

What should happen?

As your foot rolls through to a flat position, it should pronate from the supinated posture of initial contact. This essentially means that the inner arch of your foot elongates and flattens allowing the ankle to roll inwards (pronation). This action helps to absorb shock and is completely normal.

Common problems

If the foot is still pronating when mid stance is reached, the foot will roll excessively and too much weight will be transferred to the inner side of the foot. This results in a lack of stability. In an attempt to compensate for the inward movement, the knee and hip are forced out of alignment which potentially contributes to injuries such as ITB syndrome and plantar fasciitis.

The ‘fix’

In theory strengthening the small muscles in the foot can help, although I’ve had limited success with this in practise. There is some merit in global lower limb and particularly core strengthening work, ensuring that any exercises are both weight bearing and difficult enough to be of benefit. The biggest improvements are probably brought about with corrective footwear though.

Shoe recommendations:

If you stop pronating when your weight bears down on your leg during midstance, you can wear a neutral shoe. If not, over pronation is usually best corrected with a stability shoe.

Not all stability shoes are created equal, and there are several ways in which manufacturers attempt to control over-pronation. Most use some sort of physical arch support that blocks your foot from rolling too far inwards. There are other alternatives though. On Cloudace for example have introduced a new liquid injected ‘speed-board’ which only reacts when it is flexed by your feet, acting more as guidance than a rigid block.

Which of these you find most effective will depend on the severity and reasons behind any over-pronation. It’s best just to try lots of pairs for comfort as well as perhaps taking advantage of any opportunity to watch your gait in slow motion for comparison.

Toe off

Toe off, or propulsion, is the third and final stage of stance phase. It begins as soon as the heel lifts off the ground again and is responsible for driving you forwards.

What should happen?

As the weight rolls through the foot the big toe turns upwards. This triggers a chain reaction called the windlass mechanism. The plantar fascia, the band of connective tissue in the sole of your foot, contracts raising the arch of the foot. This allows the muscles down the back of your leg, particularly your calf muscles, to transmit a powerful force of propulsion using the foot as a more effective lever. The foot should be in a slightly supinated position once again with the sole of the foot facing gently inwards as you push off your toe.

Remember that spring analogy? Toe off is like taking your thumb off of the spring and watching it explode into the air.

Common mistakes

Having a stiff big toe will effect the windlass mechanism. If you can’t dorsi-flex your big toe fully (pulling it backwards towards the top of your foot) then the arch of your foot will not from as rigidly and the transfer of propulsive power through the foot may not be so efficient, putting stresses on other areas such as your achilles tendon.

The ‘fix’

Stretching your big toe by crouching down and then sitting back to stretch the sole of your foot may be helpful. If your big toe is permanently stiff and causing biomechanical problems however, then this is usually best corrected with customised orthotics, and it may be beneficial to see a podiatrist.

Shoe recommendations

Sometimes a bigger heel drop (the difference between the height at the heel compared to the toe) will help the push-off phase when the big toe is stiff or ineffective. 12-16mm heel drop is usually considered high.

Also make sure the toe box (the bit of the shoe that houses your toes!) is wide enough. This varies hugely between brands, so it’s worth trying a few.

My hints for choosing a new shoe

As you can see, there’s a lot to think about! I would first establish whether you are a heel, or mid foot striker. You can do this fairly easily by looking at the wear on your current shoes or filming yourself side on and watching a slow motion replay. Most shops can help you with this.

Then work out the severity of your pronation. Is it a normal cushioning reaction, or is your ankle collapsing inwards as your weight goes on it? Filming yourself from behind works best.

When you’ve answered these two questions, you should be able to establish whether you are looking for a stability or a neutral shoes. That reduces the options by about 50%!

Next, you can start narrowing it down by things like heel drop and toe box width. Oh, and price! To be honest once you’ve picked 5 or 6 pairs, my best advice is to try them. Most good running shops will have a treadmill and be able to film you in slow motion. But, never forget to factor in comfort. Someone can put you in your ‘perfect’ shoe and if it doesn’t feel comfortable it’s going to do nothing for you. Buying running shoes is definitely a head and heart decision. The technical spec is a good place to begin, but ultimately one pair will just feel right. And when it does, buy three pairs, because you don’t want to go through all this any time soon! Just kidding. Or am I?!

As a side note, it’s worth saying that for marathon training in particular, you would usually expect to go up a full shoe size compared to your normal daywear. You’d also expect to replace most pairs every 500 miles or 6 months depending on which comes first.

Wrapping it up!

Gait analysis is hugely complex. Here, I’ve purely concentrated on what happens at the foot during stance phase, but obviously running isn’t that one dimensional. Your knee and hip both have a role to play. As does your upper body, and your free leg. So whilst I think it’s helpful to understand what should happen when you run and how that might affect your choice of shoe, for every runner who fits the rule, there will be one who doesn’t.

Personally, I run with horrendous biomechanics. I sometimes heel strike and marginally over-pronate. I have a super wide fore foot and a left big toe which has zero movement in it. Unhelpfully, my hips are attached in a really funky position which make me look knock kneed when I run. And yet somehow, it works! I wear a basic stability shoe and get on fine with it.

So my final two pieces of wisdom would be:

  1. prioritise comfort over everything else
  2. There’s no such thing as normal, so despite this article, don’t get too caught up in the techy stuff. If it aint broke, don’t fix it.

Happy shoe shopping!

 

 

 



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