What is the Rate of Perceived Exertion (RPE) and why is it important for athletes?

Confused by the metric 'Rate of Perceived Exertion' (RPE)? Tri coach Philip Hatzis explains all you need to know about RPE, and why it is a useful tool for athletes

What is the Rate of Perceived Exertion (RPE) and why is it important for athletes?

What is RPE?

RPE stands for the rate of perceived exertion and is simply how hard you feel you are working. This makes it a subjective view of how hard an effort is.

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What is RPE measured in and how do you calculate RPE?

RPE is measured numerically with the two most common scales being 1-10 (10 is maximum effort) and 6-20 (20 being the maximum). The 6-20 scale is also known as the Borg scale and is designed to give a little more insight into effort levels. It approximately mirrors your heart rate too, provided you assume your maximum heart rate is 200 and your resting heart rate is 60.

In reality, most athletes have three efforts ingrained: ‘easy’, ‘working’ and ‘really hard’! The nuances between the different scales are often hard for athletes to identify, especially when their awareness may only be those three, and they are less aware of the subtleties of the implications of effort which we will now explore.

Is RPE time-dependent?

The interesting point about RPE is that when you ask someone how hard an effort was, it can vary as to what response you will get, this is in stark comparison to objective data. Power on the bike and pace when running are two objective data sets, which can be compared against RPE for context. If you asked someone at mile 2 of a marathon or mile 5 of an Ironman bike leg, the RPE value is likely to be lower than the value that they give when you ask them at mile 24 or mile 100 respectively even though they are likely to be at the same or lower pace, or power, than before.

 Does that make RPE useless? What are the limitations of RPE?

In a tech and data-heavy world, it can be easy to assume that such qualitative and variable data is useless. However, this can often miss the point. It is easy to see athletes who missed race opportunities because their “numbers were wrong” and those who went for it and lucked out because they “felt good”. It is clear that some athletes are constrained, and others are informed by this objective data. Often, this depends on their experience and self-awareness, or their naivety. Newer athletes are more likely to “go for it” or “back off” in case they couldn’t go the distance, whereas experienced athletes are more in tune with their effort.

Absolute numbers like power or pace are critical for new athletes, helping them to hone in on their feelings and make their RPE more accurate. For example, it is common for new cyclists to say they find hills really hard. When you ask them to ride with a power meter, it is easy to see that they hit the bottom of the hill and surge for the first third of it and then die for the rest! They have a limited perception of their real exertion and subsequently, make the hill harder than they need to. Riding with a power meter can raise that awareness and help dial into that level of effort, learning so that the next time they can essentially flatten the hill as a single power effort.

Therefore by using the numbers, an athlete can learn the true feel of threshold efforts, of  VO2 Max efforts, or of easy ones. Samuele Marcora talks about the perception of effort and being able to become accustomed to working hard. In other words, you train your RPE to normalise an exertion. Essentially, an RPE scale can help athletes understand what effort actually means.

As a result, these efforts remain fixed; what feels easy should remain easy! The measured values associated with these efforts will change with training though. For example, through a season a rider’s FTP may jump significantly from 230W to 280W, but it will still feel like threshold regardless of what the number says.

How does RPE help athletes?

To go full circle, it is this hyper-awareness of feel and RPE that good athletes need to race competitively and perform. Your watch may die in a race rendering your race plan useless unless you know what the effort is supposed to feel like. Aside from the fact that it won’t “count”, it can also mean that athletes rely on their ability to race off their RPE and associate it with an intensity to complete the race. However, even if your watch is still working, knowing what your race pace should feel like will make the race easier as you aren’t forcing a number, you are hitting a rhythm.

For racers at the sharp end, tuning into their body and racing by feel and using the numbers as a check is the only way to do it. In a draft-legal setting, you have to go with the rider in front of you. You can’t stick to a power plan. At some point in a race, you need to either go with someone or not, and a pace plan can’t rule you. These decisions are based entirely on how you feel, and in many instances, the numbers can help you make a decision.

RPE may be considered the entry-level of training metrics, and of course, it is. Still, by some level of irony, a lot of training and awareness using the “advanced metrics” like pace and power are all designed to rewire your perceived exertion into something more measured to perform. Don’t be ruled by the data; be informed by it.

Philip Hatzis is a BTF Level 3 qualified coach and Ironman certified coach. He is the founder and head coach of Tri Training Harder.

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