Updated: Sep 27
Rate of Perceived Exertion (RPE), can be used as a guide to know how hard an exercise or even a workout was. It can also be a guide to know how heavy, how much load and how many reps to perform.
E.g. Perform 3x10 squats at 7-8 RPE.
Or within a program it could be ...
week 1 = perform 3x10 squats at 4-6 RPE
week 2 = perform 3x10 squats at 7-8 RPE
week 3 = perform 3x10 squats at 9 RPE
How hard should you be working?
Well, there can be times where you might be at an RPE of 10, but very rarely. Most of the time (and to see results from resistance training) you would need to be at least 7 on the RPE scale. This would correspond to 2-3 reps in reserve (RIR). So, if you had to perform 10 reps, pick a weight where the maximum number of reps you could perform is 12 (2-RIR).
If you only perform 10 reps with a given weight but could have actually performed 15, thats most likely too light to have achieved anything. And if you do this over and over throughout a workout, you might be tired, but not actually achieve much at all!
For those older individuals and some newbie's to resistance training, you can see improvements with an RPE as low as 4 (so moderate intensity), with more reps in reserve. But like the example above, if you only perform 10 reps when you can have actually performed 15, then you you might not have achieved much from that set.
There are some downsides to RPE; which include a bit of practise using it, and knowing what RPE numbers feel like. I would recommend programming actual loads/weight still, but note your RPE too.