There's always 3 reps in reserve

You're mid-set, the weight feels heavy, and a voice in your head says that's enough. So you rack it.

Here's a question worth asking: was that really your last rep? More often than not, there were a few more in there.^1,2 Learning to tell the difference is one of the most useful skills in training, and it has a name: reps in reserve, or RIR.

What reps in reserve means

RIR is how many more good reps you could have done before you hit failure, meaning the point where you can't complete another rep with decent form.

• 0 RIR: that was your last possible rep.
• 1 RIR: you could have done one more.
• 3 RIR: you could have done three more. It felt hard, but not brutal.

Why it matters

Muscles respond to sets that are challenging, meaning hard enough that the last few reps slow down and take real effort. Sets that stop long before that are less effective, no matter how many you do.

The catch is that people are usually bad at judging it, especially beginners. Research on this keeps finding that lifters tend to underestimate how many reps they have left, particularly when a set is still far from failure.^2,3 So the rep that feels like your last often isn't.

How to use it

1. Most working sets: aim for about 1 to 3 reps in reserve.^4,5 That's hard enough to count and still leaves your form and your joints in good shape.
2. On safer movements, push a little closer. Machines and isolation work (like curls or lateral raises) are good places to go to 0 or 1 RIR.⁶
3. On heavy compound lifts, stay more conservative. Squats, deadlifts and presses are higher stakes. Keeping 2 or 3 reps in reserve there is smart.⁶
4. Take a breath before you quit. When you feel done, pause, breathe and ask whether you could get one or two more clean reps. Often you can.
5. Log it. Write the weight, the reps and how many you had left. Over a few weeks, your judgment gets much sharper.

Common mistakes

• Stopping way too early. If a set never gets hard, it isn't doing much.
• Grinding every set to failure. It's exhausting, hard to recover from and not needed for most sets.^7,6,4
• Letting form fall apart. A rep with a heaved, jerky motion doesn't count. Failure means failing with good technique.
• Comparing yourself to other people. Your reserve is your own. Judge it by how the set feels to you, not by the number on the bar.

The bigger idea

Training isn't about suffering. It's about giving your body a clear reason to adapt and then recovering well. RIR helps you do exactly that, hard enough to matter and controlled enough to keep going next week. That's the same idea behind all of my coaching: effective, sustainable and built around you.