Running. It used to be so easy. Plan the time and/or distance for your workout, put on your running gear, and go. During the run, you might have monitored pace, and perhaps heart rate, but that was it.
Of course, it is still possible to approach running as we did a few years ago, but, recent technological advancements have brought a large amount of data out of the lab and into the hands of the running enthusiast. The purpose of this new data is to capture your running form. When used intelligently, running form data can be used to make you less prone to injuries and a more efficient runner, which ultimately can make you a faster runner. Here are the most common metrics used to measure running form and how these metrics could be used in your training:
Running Form Metrics
The most common metric used to measure running form is cadence. Cadence is defined as the number of steps you take per minute. Cadence, in combination with your step length—the distance between each foot strike—determines your pace (pace = cadence x step length). So, to run faster, you need to increase your cadence, your step length, or both. Typical values for running cadence range from 140 steps per minute at slow paces to over 200 steps per minute during sprints.
*Note that some running watches and apps display cadence in strides per minute. A stride is defined as two steps. So to go from strides per minute to steps per minute simply double the value.
A second common metric used to measure running form is vertical oscillation. Vertical oscillation is a measure of the up-and-down movement (bouncing) of your torso while you are running, and is usually expressed in centimeters. The more you are bouncing, the higher your vertical oscillation. You can save energy with a lower vertical oscillation because you want more forward motion in running versus vertical. Typical values for vertical oscillation range between 6 and 15 cm.
Ground Contact Time
A third common metric on running form is contact time. Each running step consists of two phases, the stance phase (when your foot is in contact with the ground) and the flight phase (when you are airborne). Contact time is a measure of how long your foot is in contact with the ground during each step (i.e. the length of the stance phase), and is usually measured in seconds or milliseconds. Contact time ranges between 300 milliseconds during a slow jog to under 100 milliseconds when sprinting. Ideal contact time largely depends on pace, so see what works best for you while maintaining a constant pace, like on a treadmill.
Foot Strike Pattern
Although foot strike pattern is not yet as commonly available in running devices as the first three metrics, it certainly deserves to be included as a common metric. Foot strike pattern describes the part of the foot that first hits the ground during each landing, and is divided into three categories: heel, mid-foot, and forefoot strike. Although some runners use the same foot strike pattern regardless of pace, most runners tend to use the heel strike at slower paces and shift towards a midfoot or forefoot strike when running faster. Forefoot striking seems to be more of an effect of running faster, not the other way around. So, if you are prone to running-related injuries then it may be worthwhile to aim to land more on your forefoot.
The final metric to discuss is Wahoo Fitness’ running smoothness™. The idea behind running smoothness is slightly different compared to the previous metrics. Instead of measuring a very specific part of your running form, running smoothness quantifies running form based on the forces and movements in three dimensions: up and down, side to side, and forward to back. The lower the forces (impact) on the runner’s body, and the lower the amount of movement, the higher the running smoothness. Running smoothness ranges between 50 and 150. Since running smoothness is expressed as a relative value it is a unit-less value. A higher running smoothness number means you are using your energy efficiently. You can work on improving this number so your energy is not wasted.
How to Use Running Form Metrics
There are three important things to note about running form:
First, there is no such thing as a universal optimal running form. The optimal running form is different for every runner. So, unfortunately, we won’t be able to give you a standard recipe to perfect your running form. Sorry!
Second, the human body has an incredible ability to self-optimize. This means that even without dedicated form training, our movements will approach the optimal pattern given enough practice. This does not mean that dedicated running form training is not beneficial. Even for the most experienced runners the adjustments required to perfect their running form will likely be relatively small.
Finally, your body has gotten used to a particular running form, whether it is optimal or not. Changing your running form will change the stresses on your body. If you change your form too drastically it will increase the risk of injuries. Give your body time to get used to changes in running form!
Although the results in scientific studies are mixed, there appears to be a trend that elite runners use slightly higher cadences compared to non-elite runners when running at the same pace. One advantage of increased cadence is that it decreases the impact the body experiences each time it hits the ground. As a result, using a higher cadence has been suggested to reduce the risk of injury over time. According to researchers studying the effect of running cadence on injury rates, you should aim to increase running cadence by 5-10% compared to your self-chosen cadence. Based on a large body of research, it is not recommended to increase cadence much more than 10%. Because of this self-optimization as described above, the self-chosen cadence for most runners is very close to their energetically optimal cadence. Changing cadence too much would increase the amount of energy used to run at a certain pace, making you less efficient!
Since our goal is to run forward, vertical oscillation appears to be an unnecessary, wasted movement. It is often stated that vertical oscillation should be avoided. Although there is a trend that elite runners run with less vertical oscillation compared to non-elite runners, elite runners still oscillate. This makes sense—in order to avoid all vertical oscillation you would need to run with highly bent knees, which would cost a lot of energy. Our recommendation would be to focus on decreasing vertical oscillation but certainly not overdo it.
Ground Contact Time
Because of the large dependency of contact time on pace, there is no point to run at a fixed contact time. Scientific studies on the effect of contact time on running efficiency have shown mixed results. Some studies found that shorter contact times correlate with improved running efficiency, whereas other studies found the opposite. Given these mixed results we’d recommend playing around with your contact time while maintaining a constant pace—for example, by running on a treadmill—to see what works for you. One interesting finding is that ground contact time increases with fatigue. Therefore, a good way to use ground contact time during your training would be to aim to keep contact time at the same value at the end of your run as the beginning of your run.
Foot Strike Pattern
Although it is often claimed that forefoot striking is more efficient compared to heel striking, the scientific evidence to support this claim is lacking. From a pure efficiency standpoint, there is little reason to suggest adapting your preferred foot strike pattern. The fact that faster runners tend to land more towards their forefoot compared to slower runners seems to be an effect of them running faster, not the other way around. However, when looking at injury rates, it appears that heel strikers are more injury-prone compared to mid and forefoot strikers. If you are experiencing running-related injuries, it would be worthwhile to aim to land more towards your forefoot to see if this has a favorable impact on your injuries.
Running smoothness is a relatively new metric, so the exact impact of changes in running smoothness on injury rate and running performance is currently not clear. However, we at Wahoo Fitness believe it provides unique and useful information about your running form. It has been shown that experienced runners use a smoother running style compared to less experienced runners. A higher running smoothness value corresponds to lower (impact) forces on the body, and less movement. Reducing impact forces and excessive movement seems beneficial to reduce running-related injuries and improve running efficiency, so we’d recommend working towards a higher smoothness value. For example, by keeping the core more stable to minimize sideways sway and upper body rotations and landing with slightly bent knees to reduce the impact should result in a higher number. As explained above, increasing your cadence reduces the impact the body experiences each time it hits the ground, so it will also be an effective way to increase your running smoothness.