Ethiopian Almaz Ayana (Olympic gold in the 10,000 meters at Rio 2016) demonstrates the flight phase in her stride.
East African athletes generally run very efficiently. Running efficiency is determined by body posture and running form. There is little you can do about your body posture, besides shedding unnecessary body fat. But you can try to improve your running form. In this article we look at the impact of cadence and stride length on the energy cost of running and running economy.
The cadence and stride length is part of the many running metrics that your sports watch tracks for you and reports after each workout or race.
The cadence is the number of steps per minute. The stride length is the total distance per stride. A stride consists of two parts, the step phase and the flight phase. Your running speed is the product of your cadence times your stride length.
Most runners will have experienced that when you run at a higher speed you have a slightly higher cadence and a slightly longer stride length. The question now is which of the two you can best work on to improve your running economy. When you run with the lowest energy cost of running, you will be able to run faster at the same VO2.
We start with a disclaimer: it is not easy to change a running habit that has been ingrained for years. But it can be done!
Mo Farah
A great example of an elite athlete who consciously changed his running style is Sir Mo Farah. On the track, he primarily ran 5000 meters and 10,000 meters. This successful Somali-born British athlete won Olympic gold at these distances in both 2012 and 2016. After his latest victory in the 2017 IAAF Diamond League 5000 meter final in Zurich, he decided to focus more on road races. His running style was described as “resilient”. After focusing on road races, he managed to successfully change his running style and optimize his running economy.
The Theory
In our book ‘The Secret of Running’ we discuss more details of stride length and cadence. And more importantly, at what values do you run optimally? And what is actually optimal, as fast as possible or with the lowest possible energy cost of running, so as economically as possible?
A bigger stride is achieved by making a bigger step. The stride length is after all the sum of the step length and the flight length. The more flexible you are in your hips, the easier it is to make a bigger step.
With a larger stride, especially the flight phase also becomes longer. This is only possible if you also increase your flight height. The energy you need to “jump” higher cannot be used for your forward movement and speed. You will therefore have to find an optimum in step length, vertical displacement which is necessary for the flight phase (and requires energy) and cadence.
There are limits to your cadence. Many will have heard that 180 steps per minute is a nice goal. Athletes like Mo Farah have no problem running at even 220 spm for extended periods of time. But that is by no means possible for everyone. Many runners will already be satisfied if they reach 170 spm.
For this article, we show one of the many graphs from our books. We have chosen a graph that shows the ratio of vertical energy (for the flight phase) and horizontal energy (to move forward) at different cadences.
What’s the Conclusion?
So to achieve a high speed, you theoretically have the choice between increasing your stride length and increasing your cadence. It turns out that increasing your cadence is more energy efficient than increasing your stride length. This is consistent with the experience of many runners and coaches that much attention should be paid to increasing cadence. Increasing your cadence is also easier to train and the risk of injury is less.
In practice, many runners will want to increase both their stride length and cadence to run as fast as possible. A large stride length has obvious advantages, because it is not easy to increase your natural cadence by more than 10-15% in practice. Someone with a natural cadence of 160 strides per minute will struggle in the race at 180.
Advanced running watches have a metronome, where you can set the number of beeps per minute. This helps you to consciously work on increasing your cadence in training. Ron uses a metronome from the music industry for this purpose because of the louder beeps. There are even digital metronomes that can be attached to your waistband.
You may be able to increase your stride length by 50% or more. Someone with a natural stride length of 1 meter can then reach 1.50 meters in the race (if that race is not too long).
So the conclusion is that increasing your stride length should also be a very important goal of your training. However, the problem is that in practice it is not easy to maintain a large stride length for a long time. This requires strength and endurance. For most runners, stride length decreases significantly as distance increases.
Opinions differ as to the best training strategy to increase your stride length. Several possibilities are mentioned for this: strength training, hill training, interval training, jump training (plyometrics) and running track races over shorter distances.
Probably all forms of training have a contribution and need to be maintained in a structured manner over a longer period of time to be effective.
We do caution our readers not to start increasing their stride length too fanatically because of the risk of injury. Consistency and slow progress is the best in this respect!
How do you measure yourself for results?
You can study your performance to see if you are improving. With the help of the Stryd power meter, you can determine your energy cost of running and thus your running economy.
You do this by regularly calculating your specific energy consumption, or Energy Cost of Running (ECOR), in kilojoules per kilogram of body weight per kilometer.
You take the average wattage with which you have run, for example 315 Watts. If you weigh 80 kg, the specific power you have run with is 315/80 = 3.94 Watts/kg.
If your pace was 4:30 per km, then you ran 1000/270 = 3.70 m/s.
The ECOR for that race or workout is then 3.94/3.70 = 1.06 kJ/kg/km.
In previous articles, we indicated that a value of 1.04 kJ/kg/km is a fair value for a well-trained athlete. So in this example, there is about 2% room for improvement. On a marathon that is an advantage of about 5 minutes.
You could keep track of the different regular distances and see whether you are making progress by training cadence and stride length.
Our book ‘The Secret of Running’ is for sale in our webshop. Also available in German as ‘Das Geheimnis des Laufens’, and in Italian as ‘Manuale completo della corsa’.