This is probably the most talked-about subject when it comes to running technique so it's only right that I should write a blog to explain the issue as clearly and concisely as possible.
Striking the ground with the heel first when running is widely considered to be a major contributor to many ailments related to running as well as reducing efficiency, speed and running economy. When we land on the heel there is no natural cushioning of the landing and the impact is almost straight onto bony structure. Studies have shown that a classical heel striking impact causes a braking force which has been measured anywhere between 3-7 times the runner's bodyweight. For one that is a an extremely high force of repeated impacts to cushion and secondly, it means the runner is braking and thus has to accelerate again with every step which is highly inefficient.
Overstride Heel Strike - lifting toes to reach for the heel, a massive braking impact force.
On the other hand, midfoot or Forefoot striking allows the body to utilise the structures of the foot, ankle, and calf as a kind of energy-efficient spring system to cushion the landing and spring onto the next leg cycle phase. A perfect midfoot strike is a beautiful thing, a heavy heel strike looks ungainly and painful. Midfoot/Forefoot striking is, however, very demanding on these structures, and many of us are very weak in this area after a lifetime of poor footwear resulting in weak, stiff feet and ankles. Shifting to forefoot regularly shows up these issues and I would be lying if I didn't say that I see just as many issues with forefoot runners as heel strikers. However, that doesn't mean it's not more ideal, it's just that many change to forefoot too quickly, not addressed foot and ankle strength and mobility or they haven't addressed the bigger issues...bigger than just where you strike first (see later).
Textbook Landing midfoot - relaxed ankle, vertical shin, contact close to COG.
The first thing that one should understand is that its very much a sliding scale of efficiency when it comes to how one lands. One can have a very problematic hard heelstrike and one can have a very hard problematic forefoot/midfoot strike. Likewise one can do both quite well too. If you have a keen eye you can watch even the best world-class marathon runners land slightly heel strike on their way to glory. It's not the Holy Grail to be a perfect midfoot striker, likewise, it's not the Devil if your heel strikes momentarily first. One needs to look at the movement as a whole and not focus on just where you land or what shoe you wear.
When we are talking about the first point of contact, it's the leg cycle that is the issue. 99% of the time people land with the ankle at around 90 degrees - the position in which the ankle is when you stand. So if you take a step and reach your foot out as far as you can in front of you with the foot at this angle, you will naturally land on the heel first. If you lift your foot up and maintain this 90(ish) degree angle and place it straight back down underneath you, you will land forefoot first due to the angle of the shin. We have done nothing with the ankle or the foot, yet the contact point has changed. In-between those two points are a myriad of possibilities and angles all caused by how efficient your leg cycle is.
Leg Cycle
When walking, the legs act as almost pendulums from the hips, with relatively little knee bend when walking on the flat. Running however should be a much more cyclical motion where the foot drives backwards against the ground, then recovers up underneath the hips with a flexed knee driving forward before then placing the foot down again underneath the body. Effectively the foot makes a cycling motion where the downward placement of the foot coinciding with backwards drive. When the leg cycles in this way, the foot will land naturally more underneath the body. If the leg starts to act more like a pendulum, lazily swinging forwards, the foot will land ahead in an overstride position and naturally on the heel. An efficient leg cycle demands good hip extension, quad length, dominant glutes and strong hamstrings, good postural control and an effective arms swing...hence why solely focussing on how your foot is landing is rarely a successful path to running efficiency and longevity.
So the leg cycle is usually the biggest part of the heelstrike/forefoot problem and although our methodology does include working on the landing, we do most of that work when not running and allow the runner to naturally find their best landing when working on the leg cycle itself. There are however some occasions in which we directly need to focus and "play" with the landing.
The Heavy Heelstrike
A Heavy Heelstrike is the bad habit of really reaching to land on the heel. Some people manage to do this despite improving their leg cycling and it is generally due to the years of heavily cushioned shoes and can't shake the bad habit of reaching for the heel - even when landing nicely just a few cm in front of the centre of gravity. The bad habit of lifting the toes and reaching for the heel can be quite a tricky one to fix as it usually goes hand in hand with very weak and stiff feet and calves and so improving can be slow as a lot of structures need to get up to speed to catch up with the rest of the body in terms of strength and mobility. I have a whole program specifically designed for such issues, however, the constant wearing of overly cushioned poorly designed shoes is the biggest roadblock. Check out our blog on the problems with footwear to find out more.
The Forefoot Overstride
The forefoot overstride is where the client continues to overstride but now points the toes/plantarflexes the ankle to reach for a forefoot landing. This is often due to them hearing about the benefits of forefoot running or having been poorly coached. Without effectively changing their leg cycle they now are putting their feet and calves to work to try to absorb the massive impact of the overstride. This often results in Achilles and calf problems due to the overused or previously undertrained lower leg and foot structures. Another factor that comes into this is that the big glute and hamstring muscles tend to switch off. One of the common errors that happen at session 2 of our programme is that the client has remembered how it felt to land midfoot and has focussed on that feeling rather than the new leg cycle as a whole and they exhibit the more pendular overstride with a forefoot landing...often complaining that their calves in shreds the day after doing our homework drills.
One final thing to bear in mind is that I have studied a LOT about running technique and foot and ankle health. I am one of the original Foot Collective "Foot Nerds" and have done a lot of work with barefoot running and barefoot health. I preach and teach every day that barefoot is best for health and that most brands of shoes are just awful in their shape, form and cushioning. I see things from the barefoot side and a lot of people are very vocal that heel striking is just awful and they can be very black and white. What's important to understand is that striking lightly on the heel with a good leg cycle, limited overstride and negative shin angle is ok. The heel has been designed to be a rocker for you to strike and roll over when walking, so it's perfectly capable of taking SOME impact, especially if the impact is just glancing/momentary as part of a good leg cycle with good landing/cushioning mechanics.