RPE & RIR: How Hard Should You Train?
When you lift weights, it's often not enough to know how many reps to do. You also need to know how hard those reps should feel.
Should you stop when it starts getting difficult? Should you keep going until you can't do another rep? And how do you know how close you actually are to your limit?
That's where RIR (Reps In Reserve) and RPE (Rate of Perceived Exertion) come in.
They are simply ways of describing how close you are to failure.
And while the concept is simple, learning to judge it accurately is a skill that takes practice, experience, and occasionally testing your limits.
Let's start with RIR.
You finish a set and I ask:
“How many more reps could you have done?”
You say:
“Two.”
That's 2 RIR.
But here's the problem:
How do you actually know?
You need to learn what “failure” feels like
If you've never pushed a set to genuine failure, it's very easy to think you're at your limit when you're actually nowhere near it.
Your brain says:
“That's enough. I can't do another one.”
But your muscles might still have several GOOD reps left.
So when I introduce RIR to a new client, I don't expect them to magically know what 2 RIR feels like.
We need to experience it. Gradually.
Here's a simple way to understand it
Imagine I give you a weight that you can definitely lift at least 10–15 times.
Now imagine that every good rep pays you $1,000.
Your job is to make as much money as possible.
There's only one rule:
Your technique has to stay near perfect.
You don't stop because the set is uncomfortable.
You don't stop because the reps are getting slow.
You keep going until you genuinely cannot complete another good-quality rep.
Maybe you make $10,000.
Maybe $13,000.
Maybe $15,000.
The important thing is that you don't stop because you feel like stopping. You stop when your muscles actually say, “Nope, we're done.”
Now you've experienced what real failure feels like with near perfect technique.
And that's extremely useful.
Learn this with moderate weights first
When you're learning RIR, it's much better to practise this with moderate weights that you can lift for 10 or more reps.
You can safely explore what hard effort and failure feel like without putting yourself in a situation where one failed rep could be a serious problem.
Once you've built that experience, you can gradually apply the same skill to heavier weights.
For example, if you're eventually working in a 1–3 rep range, I generally want you to stay around 1 RIR rather than deliberately taking those heavy sets to failure.
By that point, though, you shouldn't be guessing blindly.
You've probably performed hundreds of reps of the same exercise.
You've learned the technique, you've experienced different levels of fatigue, and you've tested your limits with moderate to heavier weights.
That experience gives you a much better idea of when to push and, equally importantly, when not to push.
So how hard should you actually train?
Very, very generally speaking, most of your working sets will probably fall somewhere around RIR 1-3, and warm-up or ramp up sets around about RIR 4-6 just to compare.
That means you're usually finishing a working set with roughly 1–3 good reps left.
For example, if your program says:
3 × 8 reps
and we're aiming for around RIR 1-2, your 8th rep should feel like you have approximately 1–2 good reps left.
So you finish rep 8 and think:
“I could definitely do one more… and I might be able to do two.”
And sometimes, especially on a day when you feel great, your technique feels solid, and your joints feel good, you can ask yourself:
“What if I try one more?”
Then another.
And another.
And another.
You might discover that your original estimate was wrong.
Maybe what you thought was 2 RIR was actually 4 RIR.
That's useful information.
This is one of the ways you learn to judge your RIR better. You occasionally test your estimate instead of always assuming it's correct.
You don't need to do this every workout, and you certainly don't need to turn every set into a failure test.
But sometimes it's worth finding out:
“Was I actually where I thought I was?”
That's how you get better at knowing your body.
Don't worry about getting your RIR exactly right every time. If you think you're at 2 RIR and you're actually at 1 or 3, that's not a problem. The goal is to get better at judging it over time.
Some sets will be easier, some harder, and that's completely normal.
The important thing is that most of your training is hard enough to challenge you, while still leaving you enough room to maintain good technique and recover for your next set and workout.
RIR can change from day to day
Here's another important thing:
Your RIR isn't fixed.
The same weight and the same number of reps can feel completely different on different days.
Maybe you slept badly, you're stressed, you're tired, or you're simply having an off day.
On Monday, 10 reps with a particular weight might feel like 3 RIR.
On Thursday, the exact same 10 reps might feel like 1 RIR.
And that's okay.
Your body doesn't perform exactly the same way every day.
This is why you need to listen to your body and adjust when necessary.
If the program says 10 reps at around 2 RIR, but today that weight feels like 0–1 RIR, you may need to reduce the weight.
If it feels much easier than expected, you may be able to increase it.
The program gives you a target.
Your body tells you where you are today.
But how do you learn to listen to your body?
Experience.
You can't shortcut this.
Especially when you've just started lifting weights, you actually want to put yourself into some uncomfortable situations.
Not every workout. Not every set. And certainly not with every exercise.
But sometimes you need to test yourself and discover:
“What does really hard actually feel like?”
Because otherwise, you may spend months stopping your sets far earlier than you think.
As you gain experience, you'll become much better at recognising the difference between:
“This is uncomfortable.”
and
“I genuinely don't have another good rep.”
That's when RIR becomes much more useful.
RPE is basically the same thing
RIR tells us how many reps you had left.
RPE tells us how hard the set was.
A simple way to remember it:
10 RPE = 0 RIR
9 RPE = 1 RIR
8 RPE = 2 RIR
7 RPE = 3 RIR, etc.
So if I tell you to do a set at RPE 8, I'm basically saying:
Finish the set when you think you have about 2 good reps left.
The most important thing to remember
RIR isn't something you know automatically.
It's a skill.
And like any skill, it takes practice.
You'll get better at judging it by:
training consistently
occasionally testing your limits
experiencing what true failure feels like
paying attention to how your body feels from day to day
It's a long process and a learning curve.
You don't need to push yourself to failure all the time.
But you do need enough experience with hard sets to understand where your actual limits are.
Learn your limits first. Then learn how to stay just short of them.
Comments