RIR Training (Reps-in-Reserve) vs. Training to Failure: What the Latest Study Means for Lifters

Chasing muscle and strength doesn’t have to mean grinding every set to the point of failure. A new study in resistance-trained lifters found that cycling your proximity to failure (RIR) can deliver similar strength and hypertrophy gainsto always training at RIR1 (near-failure)—but with lower session fatigue.

Here’s what that means for your training in [City], [Region] and how our coaches at [Your Gym/Service] use it to help you progress without burnout.

Key Takeaways

• Similar gains: Both groups improved in squat and bench strength, and quadriceps size.

• Less grind: Training from RIR4 → RIR1 across a block reduced session fatigue while matching results.

• Skill benefit: Lifters got better at estimating RIR, especially around RIR3.

• Muscle nuance: Triceps grew more in the RIR4 → RIR1 group, but quads grew similarly in both.

What is RIR?

Reps-in-Reserve (RIR) means how many good reps you have left at the end of a set.

• RIR1 = almost failure (one rep left).

• RIR3 = comfortably strong (about three reps left).

It’s a simple way to autoregu­late training so you push hard when you’re fresh and pull back when recovery is low.

What the Study Did

• Who: 31 resistance-trained adults.

• Training: 4 days/week, upper-lower split, with squat, bench, and accessory lifts.

• Groups:

  • RIR1: All sets near failure.

  • RIR4 → 1: Started blocks at RIR4, ended at RIR1.

• What was measured: Strength, quadriceps size, triceps thickness, perceived exertion, and RIR accuracy.

What They Found

1. Strength and size improved in both groups. Squat and bench 1-RM, plus quad growth, were similar whether lifters trained at RIR1 all the time or cycled RIR.

2. The RIR4 → 1 group felt less fatigued. Session RPE was consistently lower, even though the results matched.

3. RIR accuracy improved. Practicing with RIR targets made lifters better at knowing when they were 2–3 reps away from failure.

4. Triceps had a small edge for the RIR4 → 1 group. Gains were statistically significant only there, though the difference may not matter much in practice.

How to Apply This

• Use RIR2–4 for most accessory lifts.

• Save RIR1 top sets for heavy compounds or late in a training block.

• Use deloads with easier intensity (RIR2–3) instead of near-failure, to aid recovery.

• Track your RIR weekly and review videos to sharpen accuracy.

FAQ

• Do I have to train to failure to grow?

  No. This study shows you can gain strength and muscle while training a few reps away from failure.goes here

• Is training further from failure a waste?

  Not at all. As long as volume and progression are managed, RIR2–4 sets contribute to growth without burning you out.

• How accurate does my RIR need to be?

  You’ll get better with practice. Most lifters start within 1–2 reps and improve over time, especially around RIR3.

Reference

• Martikainen O, Niiranen H, Rytkönen T, Schoenfeld BJ, Ahtiainen JP, Hulmi JJ. Influence of Varying Proximity-to-Failure on Muscular Adaptations and Repetitions-in-Reserve Estimation Accuracy in Resistance-Trained Individuals. Journal of Science in Sport and Exercise. 2025.
  Read the full study here.