The measurement of Rating of Perceived Exertion (RPE), or more simply, the feeling of exertion, is a method that is being used more and more in running. Indeed, when you encounter a route with a positive elevation gain, particular technical features or unfavorable weather conditions, it is more accurate to determine your pace by the feeling of exertion than by speed.
We use RPE in our RunMotion Coach algorithms to verify the correct execution of training sessions. Here’s how it works.
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The advantages of rating perceived exertion over raw data
Almost all runners have a GPS watch or a watch connected to it. These watches provide information on distance covered, time, speed, elevation gain, etc. Some also have a heart rate sensor on the wrist.
In principle, we can evaluate this data to check whether a training session has been completed perfectly.
However, this data is rarely very accurate.
The error tolerance of a GPS watch in open terrain is around 1%. In wooded terrain or near tall buildings, it is closer to 3%. On a 1 km route, this makes a difference of 10-15 seconds, which is a lot. You might think you are 10 seconds too slow, even though you are actually right on target!
If you wear a cardio chest strap, we think the heart rate data is accurate. If you only wear it on your wrist, the accuracy is uncertain. This is all the more true for short distances where your heart rate often fluctuates.
Finally, with regard to positive and negative altitude gain, watches without a barometer sometimes give unrealistic values. In this case, we use the elevation gain to estimate a grade adjusted pace. However, a 1 km climb with 100 m positive elevation gain on technical terrain with roots and rocks is slower than a climb with the same characteristics on asphalt.
In short, many conditions are required for the data to fully reflect the reality of the training performed.
And that’s not even counting the weather conditions. We could determine the weather based on the GPS position of the day. But how do you know whether you had a headwind or a tailwind, or whether you found a sheltered spot?
Finally, there may be factors inherent to the runner that can alter performance. These include fatigue and stress caused by personal or professional life.
The most accurate way to find out how your run went is to ask yourself! And in this regard, the assessment of perceived exertion is scientifically well documented!
The Rating of Perceived Exertion (RPE) as seen by science
RPE is a quantitative measure of perceived exertion during physical activity. It was developed by Professor Gunnar Borg. The Borg scale rates exertion on a scale from 6 to 20.
The 6 stands for rest, which can be associated with a classic resting heart rate of 60 beats per minute, and the 20 stands for maximum effort, which can be associated with a maximum heart rate of 200.
For a runner with these particular characteristics, a regular outing with an average heart rate of 150 beats per minute theoretically corresponds to an RPE of 15.
The Borg scale simplified from 0 to 10
To simplify matters for the general public, the Borg scale is also shown from 0 to 10.
We have done this in RunMotion Coach with the following information for the RPE:
- You feel very light, you are breathing through your nose and could maintain this effort for many hours
- You feel very light, breathe through your nose and could maintain this effort for several hours
- You feel light, breathe easily and can speak easily
- You feel comfortable and the pace feels natural
- You have to make a little effort to keep up the pace
- Speaking starts to become difficult and you have to concentrate to maintain the effort
- The effort becomes difficult and you can barely speak
- You have to strain to keep up the pace, your breathing is noisy
- You have given almost everything to this effort
- You have pushed yourself very hard, it is impossible to go another meter
NB: 0 would be in case of a break
The RPE is based on the runner’s physical and mental sensations. It takes into account the physical condition of the runner, the general level of fatigue, the effort management and the environmental conditions.
Numerous scientific studies have proven its value and shown a correlation between heart rate and the Borg scale. For those interested, here are some studies on this topic. The Borg Rating of Perceived Exertion (RPE) scale. The validation of the Adult OMNI Scale of perceived exertion for walking/running exercise.
How RunMotion Coach takes RPE and training load into account
RPE is a proven scale for measuring exertion. Our algorithms analyze the perceived exertion during your training session and the RPE value we expect. You can see this in the coach’s feedback after your session.
Just because you missed a session or felt you were struggling, you shouldn’t question everything. So we analyze a trend over your last ten training sessions. Similarly, if you feel euphoric during a training session: We look at the trend over the previous training sessions and the session in question.
In addition to the RPE, we ask you how you felt (you know, with the emojis):
- I felt great
- I felt good
- The sensations were average
- I didn’t feel very good
- The sensations were terrible
This allows a more precise analysis, because sometimes you manage to carry out the session as planned, but with average or not so good sensations.
We correlate the analysis of your perceived effort with your training load in order to offer you a personalized and evolving program.
We try to add further parameters. They are analyzed based on the tens of thousands of sessions we receive every week. We have some correlations, but they need to be validated with a high degree of precision.
So here’s more about why RPE is useful for running training and how we use it in RunMotion Coach. And as a reminder, your training pace will be adjusted according to your race results, which is the best way to check your progress.