It’s becoming increasingly popular to base workouts off of RPE or RIR. These two acronyms stand for “Rating of Perceived Exertion” and “Repetitions in Reserve”. They are part of a larger schema called “Auto-regulation”, or self-regulation based on how you feel in that exact workout. Not an emotional perception of the workout, but an honest look at physical readiness.
The two are basically mirrored versions of each other, with RIR having been developed primarily for the lifting world, whereas RPE was adopted from another discipline.
RPE uses a scale from 1-10 in lifting (other disciplines use different scales).
When lifting, we’re generally only concerned with ratings 5 and above. It’s kind of like earthquakes in California: unless something fell off my shelf and broke, the magnitude of the earthquake wasn’t high enough for me to care.
RPE 5: A warm-up set. The difficulty doesn’t have anything to do with the weights, but has everything to do with getting blood flowing in your body.
RPE 6: A final warm-up set. This RPE means that you have roughly 4 reps left in the tank,
RPE 7: Definitely 3 reps left in the tank – somewhat challenging.
RPE 8: Definitely 2 reps left in the tank – challenging, but only a bit more than 7.
RPE 9: Definitely 1 rep left in the tank – very challenging, takes quite a bit of focus to execute the lift well.
RPE 10: No reps left in the tank – Maximal effort and extremely challenging.
RIR functions in a similar, more directed manner.
RIR 4: I have 4 reps left in the tank.
RIR 3: I have 3 reps left in the tank.
So on and so forth, until we get to,
RIR 0: Maximal effort, zero reps left in the tank.
When given a rep range and a prescribed RPE/RIR, this makes your workouts much more open to alteration. Maybe you do your bicep curls with 25lbs for 20 reps at RIR 2 usually, but you’re feeling especially strong today. You decide to push it and you end up doing 25 reps at RIR 2 this workout. You’ve added a bit more volume and gotten stronger now! If you have a particularly rough day, maybe you only do 19 reps at RIR 2. This allows you to foster better recover on bad days, and push the limit and get extra volume on good days.
How do you know what RPE or RIR you’re at? Practice! Get to know your body. Start taking isolation exercises or machine exercises to failure and seeing how it feels. The only way you get better at gauging RIR or RPE is by making yourself aware of it in the midst of doing a set. I always recommend learning this method by going to failure on little exercises regularly for a while. After a little bit, you’ll start to feel what being 1-3 reps away from failure is like. It’s a great skill to have, and one I believe should be practiced every session!