Playing with my PEL

Have I ever mentioned I am a researcher by profession? I don’t do it for a living these days, having got a bit burnt out as I specialised in social research and it led me down some tricky alleys during the early 2000’s. However, I am a researcher by personality and if I am interested in something, I am compelled to read around the subject.

Training my legs and heart to do a half marathon is not enough. I have to read everything I can on the subject too. Part of my reading has included the recently published “Half Marathon” by the venerated Hal Higdon. (I will be posting my review of the book at a later date). Hal is a big fan of heart rate training. He likes to “keep it simple” and his advice is “run a lot at a 50-60% of your maximum heart rate and a couple of times a week at 80-90%”. I like the simplicity of this.

However…….. I don’t have a Heart Rate Monitor. Of course I do have a stop watch and I can check my pulse, but who has the desire to stop every few minutes during a run to take their pulse? I’d never get home! A bit of digging on the Internet revealed that there are very close correlations between the Heart Rate training  zones and the levels on the PEL.

Perceived Effort level – PEL, also known as Rated Percieved Exertion  – RPE, is based on a scale developed by Gunnar Borg in 1970 and further refined over the subsequent 30 years. He has also developed a scale for rating pain but I think I may leave that for another day.

As Borg states:

*A high correlation exists between a person’s perceived exertion rating times 10 and the actual heart rate during physical activity; so a person’s exertion rating may provide a fairly good estimate of the actual heart rate during activity (Borg, 1998)

I have of course crossed paths with this idea before but had not realised how useful it could be with my running. I was a bit concerned that it was a self-reporting scale and therefore a highly subjective training tool, one that I would use as an excuse not to try too hard and make excuses for myself. Guess what? I was wrong.

The original scale goes from 6 (no exertion at all) up to 20 (maximal exertion). Each increase on the scale was approximately equal to a 10 beats per minute increase in maximum heart rate, i.e. 17 on the scale was approximate to a 170 beats per minute. It looks like this

As runners, of course this make perfect sense to us, but not everyone understood how to use it and so the scale was redeveloped into a 10 point scale and also equated to heart rate training zones:

I love the smiley at RPE 10. We’ve all been there.

The scale has been widely tested and adapted, with some sports scientists even breaking it down to a 100 point scale. However, it has generally been concluded that it is an effective way of measuring training load. Just one example can be read here from a 2013 Australian study Reliability and Validity of RPE

Based on this scale, I have been making a conscious effort to monitor my PEL during my training runs. This has led me to reach a number of conclusions.Firstly, you have to concentrate really hard to monitor your effort when you are running and that there are a number of factors that change the effort and that more than one may occur just on a single run. For example, the gradient  – even that small incline has a distinct impact on your effort level, the weather – a recent warm spell pushed my PELway up the scale, how tired you are from other runs and even humidity levels. Constant feedback assessment and adjustments are necessary and this takes concentration.

Another interesting thing I have learned is that every run must be judged in isolation. A recent 5k run at a PEL 7 was surprisingly comfortable. A 1ok 3 days later at an PEL 5-6 was much less comfortable on that particular day.

One learning that surprised me was that on long, slow runs, about 4 kms in, my body adapts and changes and the effort required to maintain a PEL 5-6 significantly drops and I need to up my pace to keep up the effort.

It has also taught me to have more confidence in myself. I mentioned the recent 5k at a PEL of 7. This was on the plan as a Race Pace run. I was unsure of what that pace would be and referred back to Hal’s writing which said to aim for a 7-8 PEL. I was unconvinced I would be able to maintain this effort over that distance, or of the pace it would result in. I was wrong. I was able to maintain it and even had a strong finish, taking it up to a 8-9 effort. The pace turned out to be 10 seconds per km faster than I had expected.

My final observation on training with the RPE scale is that it is helping me to get fitter and faster. Yesterday I ran 11k on my LSR – the furthest I have ever run. It was done at a 5-6 PEL and I had to keep reminding myself to slow down, walk even. Despite this, I was running at the same pace I had been running just 5k only 4 weeks before!

Have you tried using the RPE/PEL scale in your training? What experiences did you have?