Mastering RIR: The Smarter Way to Build Muscle and Strength

RIR, or Reps in Reserve, is one of the most powerful tools in your training toolbox if you know how to use it properly.

Here's how to get the most out of it without overcomplicating your training.

Start With Breathing Room...

You don't need to go all-out immediately when you begin a new program or mesocycle.

Start your sets with around 3 RIR, which means you could do three more reps if you really had to. This gives you space to build and sets you up for steady progress. From there, increase the load or reps by small, manageable amounts each week—nothing drastic, just enough to keep pushing forward.

Build Up to the Limit

The goal is to gradually work your way from 3 RIR to 0 RIR (actual failure) over the course of a program.

This approach keeps fatigue in check while maximising hypertrophy/strength training.

Eventually, you'll stall. That's fine. When progress stops, it's time to change programs and recover—either with a deload, lower volume week or even a complete break from hard training. Then, restart the process again.

It's Simple…

RIR training doesn't have to be complicated, but it does take a program or two to learn what your real RIR feels like truly. Most people struggle here.

Let's break down some common problems:

Common RIR Misjudgments

You think your 3 RIR is actually 3, but it's probably more like 5.

You think your 3 RIR is accurate, but it's really more like 1.

You hit a set and said it was 0 RIR, but could you actually have done another rep on the hack squat?

You're solid at knowing what 3 RIR feels like, but get lost between 2 and 0.

These are super common. And every week that you misjudge RIR is a week of less-than-optimal training.

But don't worry—there's a solution.

How to Improve Your RIR Accuracy!

Here's how to dial things in and make your training as effective as possible:

Stick to consistent load/rep schemes week to week. This makes it easier to track your performance and progression clearly. (This is why we follow a program)

Track your rep strength across the mesocycle. This gives you feedback. If you fail at the end of the program, you can look back and see how accurate your 3 RIR estimates really were.

Use this feedback to tweak your starting intensity for the next meso. Now you know if you overshot or undershot.

You can use last week's performance to guess this week's starting RIR better.

Over time, this becomes second nature.

Adapt as You Go.

Things don't always go to plan, and that's okay. Here's how to make in-session adjustments based on how sets actually feel:

If your plan was 2 RIR, but the set felt like 0 RIR: Reduce the load or reps slightly in the next set to stay on target. You still want to challenge yourself, but don't go into the red too soon.

If your plan was 0 RIR, but the set felt like 2 RIR: Add a bit of load or reps to push closer to failure as intended.

These micro-adjustments help you manage fatigue, stay on track, and avoid spinning your wheels.

In conclusion:

RIR-based training works really well, but only when you're honest with yourself and consistent with your data.

Take time to learn your true RIR, track your performance, and use feedback to improve each training session/cycle.

This isn't about crushing yourself every workout—it's about training hard, training smart, and progressing with purpose.