What does RIR mean?
After a set, ask yourself: how many more reps could I have done with the same form? The answer is your RIR. If you had 2 reps left in the tank, your RIR was 2. RIR 0 means you went to failure.
The scale from 0 to 4
- 0 left: you could not have done another one.
- 1 left: one more would have gone, but only just. The last rep is slow.
- 2 left: heavy, and the last reps take focus.
- 3 left: challenging but controlled.
- 4 left: clearly hard work, but with a good margin.
With 5 or more left, the set is closer to a warm-up than a working set. Further from failure than that, it also gets hard to judge accurately.
You may also come across RPE, an effort scale out of 10 where RPE 10 means you could not have done another rep and RPE 8 roughly equals 2 reps left.
How to judge how many reps you have left
A few signs help:
- Speed. When reps slow down clearly even though you are pushing as hard as you can, you are getting close.
- Form. If the movement starts to change, for example your hips rising before your chest in the squat, you are close to the limit.
- Straight after. Ask yourself as you put the weight down, not after your rest.
Test yourself now and then
A good way to learn is to take the last set of a safe exercise all the way to failure every so often, such as dumbbell curls or leg extensions. Notice when you think you have 2 left, then keep going until you cannot do another rep. If you got 5 instead of 2, you know you tend to underestimate yourself.
Beginners often underestimate what they can do
Many people new to the gym end a set when it starts to burn or feel uncomfortable, long before they are actually done. But feeling heavy is not the same as being unable to do another rep.
That is why a beginner's estimate is often off. If you think you have 2 left, it could just as easily be 4 or 5. Early on that matters less, because your body responds to less when training is new. After a few months it becomes more important that your sets are genuinely hard.
Form still comes first. Learn where your limit is with the test above on safe exercises, not on heavy compound lifts.
Burning muscles and heavy breathing are normal. If something hurts, rather than just feeling heavy, stop the exercise and have it looked at by a doctor or physiotherapist.
How close to failure do you need to go?
For building muscle
Your sets need to end fairly close to failure to do their job. For most sets, 1 to 3 reps left is enough. If you use light weights and high reps, you need to go closer, or the set ends up as little more than a warm-up.
Smaller exercises, such as lateral raises, curls and leg extensions, can be taken closer, sometimes all the way to failure on the last set.
For getting stronger
Strength is built from lots of heavy reps with good form. You rarely need to go to failure for that. Stop with 1 to 3 reps left instead, so every rep looks like the one before. This matters most on the squat, deadlift and bench press.
Failure sparingly, and on the right exercises
Going to failure on every set costs more recovery and often makes your next set, or your next session, worse. Use it as a tool, not as the default:
- On the last set rather than the first.
- On machines, cables and smaller dumbbell exercises, where you can let go of the weight safely.
- Not on heavy squats or deadlifts, where form tends to break down when you are most tired.
- On the bench press only with a spotter, or with the safety bars set in the rack.
RIR and progressive overload
RIR tells you when it is time to add weight. Say you are doing three sets of 8 on the squat and aiming for 2 left on each set:
- Week one: 70 kg for 8 reps, with about 2 left on the last set.
- Week two: 70 kg for 8 reps, but now with 3 or 4 left.
- Week three: 72.5 kg, and you are back to about 2 left.
More reps left at the same weight is a sign you have got stronger. That is progressive overload in practice. If you instead hit 0 left before reaching 8 reps, stay at that weight for a while longer.
RIR also ties in with the reps you choose. If you are doing 10 reps with 2 left, pick a weight you could manage about 12 times. Read more in the guide to sets and reps.
How BIP helps
In BIP you log the weight and reps for every set, and in your next session you can see what you managed last time. The log and your own sessions are free in the training log. The programmes BIP builds often show an RPE value next to the exercises, telling you how hard the sets should feel. The first week of a programme is free in the generator, and with Premium (99 kr a month) BIP builds your next week every week based on what you actually lifted.
Frequently asked questions
Do you have to train to failure to build muscle?
No. Sets that end close to failure, with 1 to 3 reps left, go a long way for most people. You can use failure now and then, on the last set of a safe exercise.
Should beginners think about RIR?
Yes, as a rough guide. Aim for 2 to 3 reps left, focus on your form and expect to be able to do more than you think.
Do I need to write down RIR for every set?
No. Noting it for the last set of your main exercises is often enough. What matters most is having your weights and reps in your log.