There is a lot of discussion in the media and running circles about running technique, and specifically heel strike vs forefoot and the pros and cons of each. Unfortunately almost all the discussions have over simplified the topic and miss a few key points.

Before I go into more explanation let me summarise by saying:
1. There is nothing wrong with heel striking depending on where the rest of your body is when your heel strikes the ground.
2. Changing to a fore/mid foot strike doesn’t necessarily improve your running or decrease your risk of injuries and may even increase the risk of injury.
3. Forefoot strike is not necessarily a more effective, more economical way of running. Read on to find out why.

First of all let’s look at what runners actually do in races, not on a treadmill (where the majority of studies are carried out). Depending on which study you read somewhere between 65-85% of elite runners heel strike during a marathon. So if the majority of elite distance runners heel strike why is everybody trying to change to a forefoot strike? As with most things the answers lie in the shades of grey that most discussions on foot strike completely miss.

Speed
The faster you run the more likely you will forefoot strike. Try sprinting for the bus and see if you still heel strike. If we are going to have a discussion on heel vs forefoot strike we need to put that in context of speed. A 400m runner that heel strikes is probably very inefficient, a marathoner who heel strikes may not be. When talking about speed we can’t talk about absolute speed since for a Kenyan marathon runner 3 minute kilometres are comfortable whereas for the average runner it is a sprint.

 

Heel strike and elastic energy
There is an idea that if you heel strike you can’t take advantage of the elastic energy that can be stored in your Achilles tendon and used to propel you forward. This is based on the notion that it is the little stretch you get between when your forefoot hits the ground and when your heel touches (or moves towards the ground) that loads the Achilles tendon. But even if you heel strike the forward movement of the lower leg relative to the foot will load the Achilles if it happens rapidly enough. If you look at the diagram below you will see in figure 1 that if you heel strike out in front of the body the lower leg has to move through a large range before it stretches the Achilles. During this time a lot of energy will leak into the ground. If however, like in figure 2, the heel strike is near or underneath your centre of mass the lower leg doesn’t have far to travel before the Achilles becomes loaded.

Different types of heel strike
It’s not as black and white as heel strike and forefoot strike. We have midfoot strike and also what I call a glancing heel strike. To understand a glancing heel strike is to understand why elite runners can heel strike and be very efficient and back of the pack runners can heel strike and be very inefficient.

Glancing heel strike
A glancing heel strike has two main distinctions from a normal heel strike:

• The foot lands close to or under the centre of gravity.
  The motion of the leg just before contact is either slightly backwards or downwards.

This differs to normal heel strike, which occurs when the foot is out in front of the centre of gravity and the motion of the leg is forward. Let’s look at both of those in more detail.

Foot landing position
If the foot lands out in front of the body then a braking force occurs in the opposite direction of travel. If the foot lands underneath then this minimises any braking force.

Leg motion
If the leg is moving forwards at foot contact then once again a braking force occurs. If the leg is moving backwards or downwards at contact then as the foot comes to rest momentarily on the ground the resultant momentum drives the rest of the body forward. Neither of these are dependant on which part of the foot hits the ground – it can happen with either heel or forefoot.

Effect of shoe on foot strike speed
The lower the heel on your shoe the more likely you will land mid/forefoot regardless of speed. But barefoot runners can still heel strike. Despite what you read, barefoot or minimalist running isn’t a cure for heel striking but A higher heel will lend itself more to heel strike and the higher the heel the more likely (in general) you are to make contact with the ground out in front of your body.

What’s the ideal heel for a shoe?
That depends on the person, the speed they run at and the distance they run. For a 200m sprint you wont need any heel at all since your heels won’t touch the ground. For an ultramarathon a little bit of support under the heel is probably a good thing as the cumulative load on the calfs and achilles is reduced with a slight heel.
How much support? I recommend anywhere from 2-8 mm depending on the individual. Go too low and it can overstress your calves and achilles.

Should you change from heel strike to forefoot strike?
The focus shouldn’t be on what part of your foot hits the ground but where the rest of your body is when it hits the ground. Minimising braking forces and conserving forwards momentum is the goal as this will improve running economy and decrease your risk of injury. To do this you need to land more under your centre of gravity and have the leg travelling backwards or downwards at point of contact. Unfortunately without slow motion video it’s very hard to determine where your body is when your foot hits the ground. A variable that is easier to measure is your stride rate. In general the lower your stride rate the more chance there is of your foot landing out in front of you.

Stride rate
A quicker stride rate, or cadence, reduces the chance of your foot landing forward of your body and this is of far more importance than which part of your foot hits the ground first. Changing your stride rate will take time and conscious effort. Be aware it will also load muscles differently so you should make any change gradual. Start by focusing on stride rate during speed sessions (you are doing speed sessions aren’t you?). Particularly notice what happens to your stride length when you fatigue. In many runners fatigue increases stride length making you less effective.

Is there an ideal stride rate?
You may have read that 90 is the magic number that we should all be aiming for. This is untrue and stride rate has a number of variables which change from athlete to athlete. Some athletes when they increase their speed increase stride rate, others increase stride distance, others do both. The key point is that if you increase stride length then that length should not come out in front of you, it should come from the distance the leg goes behind your body.

Hip extension
One reason why we fatigue as our cadence drops and the foot lands in front is that we may lack hip extension. This means we get more stride length in front of the body rather than behind it. Developing greater dynamic hip extension will help increase stride length without the foot landing forward of the body. If you have plenty of available dynamic hip extension then it may be the glutes and/or hamstrings don’t have sufficient strength to propel you forward far enough to allow a longer stride.

Should you change your cadence?
First of all become aware of your cadence and how it changes – if your cadence slows as speed increases or slows when holding the same pace as you tire you can assume you are over-striding. Quicken your stride rate slightly to get your foot back towards your body when it hits the ground. If your cadence is pretty constant at different speeds and less than 90 there may be nothing wrong with that. The only real way to know is to get someone to video you and look at it in slow motion. But it is still worth playing around with cadence to see if a small change feels more economical. Experiment in your speed sessions and see if you feel any better with a slightly higher stride rate. If you do then gradually start to work that into slower speed running. Like any change it should be increased gradually to give the body a chance to adapt. But whether your cadence is 84 or 94 or 104 you need to look at the whole body to determine if that’s a good or bad thing. There is not a magic number that applies to every athlete, our bodies are all individual. So don’t worry if you hit the ground with heel first, there may be nothing wrong with that, despite what you may read in some seemingly scientific articles. Unless you take into consideration the position of the rest of the body when your foot hits the ground it is meaningless.