How to monitor Training Intensity

It is common for people to go to the gym without a plan, spend 15 minutes on a foam roller, walk another 5 on the treadmill and then spend the next 30 minutes lifting weights that are way too light for them. They then 'call it a day', pack up their belongings, chug their sports recovery drink and head home. These people have wasted their time.

In order to make progress, you need to follow the Overload Principle. The Overload Principle is the concept that in order to make progress and gain strength you need to challenge the limits of the body and overload your capacity. The concept holds generally true. Translated to strength training, in order to get stronger, you need to lift heavy weights. While you don't always need to go to failure, you do need to work hard enough for the body (and the brain) to decide that it is worth it to put on more muscle. The same can be said for conditioning. You need to go hard enough that the brain says 'hold on, we can't keep up with production! Let's make the heart stronger, add some energy resources and pump in some new blood!" This comes down to a question of Intensity. 

Intensity is pretty much what is sounds like: how intense is the effort.

I like to use a scale called the Rating of Perceived Exertion (RPE). RPE is a subjective measure of intensity, usually on a scale of 6-20 or 1-10 depending on the training day.


RPE for Conditioning

For conditioning days I use the 6-20 RPE. The reason it starts at 6 and scales up to 20 is because it is meant to correlate with your heart rate when you multiply it by x10. A rating of 6 would be considered 'no effort', or 'rest', so an RPE rating of '6' should be about 60 beats-per-minute if you were monitoring it with a heart rate monitor. An effort of '20' would be an all-out exertion and correlated roughly with a 200bpm heart rate.

During a race, you are going to be running at an RPE of 20/20 by the end, but you may start out as low as 12/20 depending on the duration. Remember that the length of effort can play a significant role on your RPE. You wouldn't run a 10km race at the same pace as a 200m sprint, but you could finish both races with an RPE of 10/10.


RPE for Strength

For strength sessions I use the 1-10 RPE. This one is a little bit harder to judge. A 10 is pretty clear: you can't perform any more reps. A 1-9 is a little tougher. Usually, I recommend training at an RPE of 6-9. At a 9 you could probably perform another rep, but you might have to break form to do it. At 8 you are confident you could perform another rep, but only one, with clean technique. At 6-7 you should be confident that you could perform 2+ reps without compromising form. As you gain more training experience your RPE will become more accurate and you can use it to judge your weights and reps in future workouts based on past RPEs.

(Take our friend with the pickle jar for instance. I imagine he would rate his effort at 10/10, because he is using his maximum strength just to get one rep in.)


Technical RPE vs Absolute RPE

Whenever I am talking about RPE I am talking about your Technical RPE, which would be based on your Technical Rep Max. To have the conversation about RPE we need to first differentiate between Technical Rep Max (#TRM) and Absolute Rep Max (#RM). Your 1TRM is the maximum amount of weight your can lift for 1 repetition with PERFECT form. You can extrapolate this same concept to your 10 rep TRM (10TRM) which would be the most amount of weight you could lift for 10 reps with perfect form. In contrast, your Absolute Rep Max (1RM) is the maximum amount of weight you can lift regardless of form. For experienced or expert lifters the 1TRM and 1RM should be extremely close, if not identical (for example, Chris Duffin who is a world record holder in the Squat). For the average Joe (or Joanne) there is more likely a differential.

For the sake of athletic performance and injury resilience the TRM is more important, which is why I use it for judging RPE for Strength Training. In my mind, it doesn't matter how much weight you can manage to grunt off the floor if your knees are caving in and your back looks like an scared dog to do it.


How accurate is RPE?

Like anything, being accurate with your RPE will take practice. After a while, you will be able to judge extremely accurately where you heart rate is at while you are training and how many reps you have left in the tank.

The quickest method to practice this skill:

  • Conditioning: Use a heart rate monitor and compare it to your subjective score.
  • Strength: Pick an RPE and then go to failure. Learn from it and commit the feeling to memory.
  • Practice, practice and more practice



How to use RPE to monitor progress

RPE is only useful for monitoring progress if you have practiced it and you use it consistently. If you record your RPE regularly, it is easy to monitor your progress. As you become stronger, your RPE for a weight at a given rep scheme should decrease over time.

For example: during week 1 I deadlift 215 lbs for 5 reps at an RPE of 9. After training, on week 3 I deadlift the same amount of weight for 5 reps, but my RPE is 7. Now I know it is time to either increase the weight or increase the reps, depending on my training goal.

The same concept applies for conditioning training, except your have the added benefit of using your heart rate to validate your progress. As you train and become fitter, your heart rate at a given workload should decrease. To reach that same heart rate you will need to increase your training intensity to get the same training stimulus as before.


The Cliff Notes

  • RPE is the subjective Rating of Perceived Exertion
  • RPE can be used to monitor both strength and conditioning training
  • During conditioning training, use a 6-20 scale which correlates with your heart rate when multiplied by x10
  • During conditioning training use a 1-10 scale, where 10 is your max effort and 1 is as easy as it gets
  • RPE is accurate, as long as you practice and use it consistently
  • RPE can be used to monitor progress and determine progression

Remember, intensity is only one way to add variability to your training and increase overload, but it is one of the most important. In the next few weeks, we will talk about other ways to increase overload and how you can take advantage of the FITT principle to make progress.

Best of luck on your training.

-Mark Murdoch, B.Kin, Doctor of Chiropractic Student (UWS)

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Author: Mark Murdoch, Kinesiologist, Chiropractic Student. Have questions? Email me. I want to help!