Understanding RIR (Reps in Reserve):
The Key to Smarter Training and Better Results
When it comes to strength training, most people know that intensity matters. But how do you actually measure how hard you’re training without overdoing it—or leaving gains on the table? That’s where RIR, or “Reps in Reserve,” comes in. In this article, we’re going to break down what RIR is, why it’s one of the most effective tools for gauging training intensity, and how you can apply it to build more muscle, strength, and endurance.
You can also watch an overview of RIR, here:
What is RIR in Weight Training?
RIR stands for Reps in Reserve. It’s a simple yet powerful way to measure training intensity by estimating how many more reps you could perform in a set before reaching failure.
For example: if you finish a set of squats and feel like you could have done 2 more reps before failing, that’s an RIR of 2.
Here’s a quick breakdown of the scale:
- RIR 0 – You trained to absolute failure; no reps left.
- RIR 1–2 – Very close to failure; you could only grind out 1–2 more.
- RIR 3–4 – Moderate effort; a few reps left in the tank.
- RIR 5+ – Light effort; plenty of reps left before failure.
👉 Using RIR lets you push hard enough for growth without constantly training to failure, which can increase injury risk and hinder recovery.
Why RIR Matters for Muscle Growth and Strength
Many lifters either go too hard—training to failure every set—or too easy, leaving progress behind. RIR provides the middle ground.
Benefits of Training with RIR
- Maximizes hypertrophy – Studies show you can build muscle effectively within 1–3 RIR without always hitting failure (source).
- Protects recovery – Failure training is taxing on the nervous system. RIR ensures you can train consistently without burning out.
- Improves longevity – By auto-regulating effort, RIR keeps your training sustainable across months and years.
How to Use RIR in Your Training
Match RIR to Your Training Goals
- Strength – Stick to lower RIR (1–2) on heavy compound lifts like squats, bench press, and deadlifts.
- Hypertrophy (muscle growth) – Aim for 1–3 RIR on accessory lifts to maximize stimulus while maintaining form.
- Endurance or technique work – Train at 3–5 RIR to build work capacity and refine movement patterns.
Apply RIR Across Training Phases
- Accumulation phase – Use 3–5 RIR to build a base and perfect form.
- Progressive phase – Ramp intensity with 2–3 RIR.
- Peaking phase – Occasionally push to 0–1 RIR to test strength and peak performance.
RIR vs RPE: What’s the Difference?
RIR is often paired with RPE (Rate of Perceived Exertion).
- RIR 2 = RPE 8 (You had 2 reps left, so the set felt like 8/10 difficulty).
Using both methods together provides a more accurate measure of effort.
Common Mistakes When Using RIR
- Underestimating reps left – Beginners often think they’re closer to failure than they really are.
- Always training at 5+ RIR – Leaving too much in the tank prevents growth.
- Never training to failure – Occasionally pushing to RIR 0 helps you recalibrate your effort.
Practical Tips for Getting Started with RIR
- Track your RIR in a logbook – Note effort levels to spot trends over time.
- Test true failure occasionally – On safe lifts (machines, isolation work), go to RIR 0 to gauge accuracy.
- Auto-regulate intensity – On low-energy days, stay at 3–4 RIR; on good days, push closer to 1–2 RIR.
- Pair with progressive overload – Increase weight, reps, or sets while keeping RIR steady for long-term growth.
RIR for Beginners vs Advanced Lifters
- Beginners – Start with 3–4 RIR while learning technique. You’ll still grow because nearly everything is a stimulus at this stage.
- Intermediate lifters – Train mostly at 1–3 RIR to balance stimulus with recovery.
- Advanced athletes – Use 0–2 RIR strategically during peak phases to maximize performance.
RIR vs Training to Failure
One of the most common questions is whether training to failure is better than using RIR.
- Failure training can help build mental toughness and provide maximum muscle fiber recruitment.
- RIR-based training allows for more sustainable progress, less fatigue, and better long-term adherence.
👉 The best approach? Use failure training sparingly, and rely on 1–3 RIR for most sets.
FAQ: RIR (Reps in Reserve) Training
- What does RIR mean in lifting?
RIR stands for Reps in Reserve, a way of measuring how many reps you had left before failure. - How many RIR should I use for muscle growth?
For hypertrophy, aim for 1–3 RIR on most sets. - What’s the difference between RIR and RPE?
RIR = reps left in the tank. RPE = how hard the set felt on a 1–10 scale. They complement each other. - Should I always train to failure?
No—failure is useful occasionally, but RIR provides a smarter, more sustainable way to train. - Is RIR good for beginners?
Yes. Beginners should start at higher RIR (3–4) to focus on form and safety. - How do I know if I’m estimating RIR correctly?
Test failure occasionally on safe lifts, and compare your estimate with reality.
Final Thoughts: Training Smarter with RIR
RIR isn’t about working less—it’s about working smarter. By balancing intensity, recovery, and progression, you’ll see consistent gains without burnout.
Whether your goal is muscle growth, strength, or endurance, Reps in Reserve is one of the simplest tools to optimize your training.
👉 Want to actually apply more of these smart training strategies? Check out what we have to offer at Tailored Coaching Method, with our Training App, The Tailored Trainer, or apply for Customized Training and 1-on-1 Coaching. You can also follow Cody McBroom on Instagram for more science-based coaching insights.
