This is not a generic article recommending low heel recovery. In fact the aim here is to get people questioning the effect of this trend in the coaching of sprint mechanics. For those who don’t know, heel recovery is a term used to describe the movement of the foot during the swing phase of sprinting. Low heel recovery (LHR) is keeping the foot closer to the ground. This is often recommended for the first few steps of a sprint. High heel recovery is cycling the foot up closer to the height of the pelvis, which occurs to the greatest degree during max velocity.
Coaching LHR for speed seems to have exploded in popularity. People note that some elite sprinters display a light drag of the toe when leaving the blocks and try to implement a similar technique with all athletes. Rather than experimenting to see what is effective for each individual athlete, the speed training community has largely assumed that these mechanics are effective and then made feeble attempts to explain why. These attempts include claims that LHR does things like reducing air time, allowing correct direction of force application, and keeping proper acceleration positions.
Key components of a good start:
- Extension of the body at toe off.
- Foot contact roughly under the hip on the first contact. Lower level athletes will likely contact slightly in front, high level slightly behind. Contact gets slightly more in front as the sprint progresses.
- The foot moving roughly straight down into the ground in the moment before first contact. This occurs when backward foot action compensates for forward movement of the body. Movement of the foot before contact gets slightly more forward as the sprint progresses, and again higher level athletes are able to execute this to a greater degree further into the sprint.
- No excessive air time. The components above can often be performed easily for at least the first contact if an athlete does an exaggerated push and spends extra time in the air. Being able to execute with competitive sprinting quickness is the goal. Appropriate air time after the first push of a sprint is generally 0.05-0.07 seconds, and it grows from there.
These components of a good start can occur with or without LHR. As an example the picture below shows the moments of toe-off on the first push and the first foot contact following. This start did not use LHR, and the acceleration positions are right on point. There is no reason this athlete needs to sweep his feet just above the ground in order to achieve this. The full start is shown in the videos coming up.
Appropriate air time can also occur with or without LHR. Efforts to use LHR and almost completely eliminate air time result in major braking forces. With these things in mind, IF low heel recovery is effective for an athlete, I do not believe it’s because of proper positioning or decreased air time.
I believe generating more momentum in the swing leg is the potential benefit of low heel recovery. But we have to consider that with the foot low, the leg is harder to swing.This is where things get tricky. LHR may create more momentum from one stride, but it requires more work be done in hip flexion on the swing leg and in extension of the plant leg. More work takes more time. So there is give and take between maximizing momentum from each push and completing the push quickly. To optimize acceleration we have to find the correct balance between these. Here’s the key:
The point on this spectrum where acceleration is maximized varies from athlete to athlete.
This is influenced by many factors such as power relative to body weight, elastic vs muscle-driven force, height/proportions, and probably 100 other things. The human body is extraordinarily complex. We do not have the ability to calculate optimum heel recovery for any athlete on any stride. Thus it makes no sense to force athletes into an LHR model or any model for that matter. The goal should be extension and a quality foot contact. Heel recovery should take care of itself.
As for a model, the best we can do is maybe identify trends. For example I do not expect a tall, undeveloped athlete to utilize LHR successfully, even on the first step. In higher level athletes I expect to see a trend of lower to higher heel recovery, but that does not necessarily mean they sweep the foot within an inch of the ground on the first step. And it certainly does not mean they do that for several steps. Looking at the start in the video, I do not want to mess with it by trying to utilize lower heel recovery.
Physical abilities influence technique. I have talked about this in the speed context already in Speed Science. The same concept applies to any model for any movement. We have to recognize there will always be a gap between the theoretical ideal model and what is currently ideal for a given athlete, and we need to be wary of forcing athletes to perform a movement strategy to a degree they are physically incapable of executing effectively.
In the case of heel recovery, there may be a trend for great accelerators to use LHR to some degree. Exceptional power may be what makes this work. They are moving a longer lever, but it does not slow them down like it does a low level athlete. This allows them to gain more momentum from each push without much sacrifice of quickness. This does not mean all athletes can use LHR successfully.
Even in the case of an elite accelerator, do not forget the simple physics. In acceleration, velocity is gained with each push. That means ground contact time should decrease on each push. That means the leg swing needs to get quicker on each push. That means the lever (swing leg) needs to shorten as you accelerate. It makes no sense to keep the feet within an inch of the ground for several steps. Stop over-doing low heel recovery!Christian Coleman shows an example of what realistic LHR might look like in an elite sprinter.
- 1st push from blocks: medium heel recovery. Because of the quickness of the push from the blocks, there is usually less time to swing the leg during this first push than on the next one. Thus the leg swing must be quicker, so heel recovery is higher.
- 2nd push: toe drag. Coleman is the type of athlete that can use extreme LHR effectively.
- 3rd push: foot is already starting to come up.
- 4th push: little higher.
- 5th push: high heel recovery already.
The next video compares a natural sprint start to what it looks like when people mess things up with LHR. (Example 1) Most people would probably identify the first example as a bad start on video, but I still regularly see people practicing like this. (Example 2) What’s funny is I was trying to be really quick for this example, but my stride rate was actually slightly lower than on my natural start because the contact time was significantly longer. Plus the strides are shorter. This may not look awful live, but it’s bad technique. (Example 3) Natural sprint start checks the boxes (extension, backward foot action, contact under hip, not excessive air time).