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Reps in Reserve (RIR): What You Need to Know

Kinsey Mahaffey
Kinsey Mahaffey
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Most lifters are familiar with calculating percentages of their 1 Rep Max (aka, 1RM, the maximum amount of weight that you can lift for 1 repetition of an exercise) to choose the appropriate weight for an exercise based on their desired intensity for the day.

What if you don’t know your 1RM for an exercise, but you still want to make sure you get those #gains? The Reps in Reserve (RIR) method is a quick and relatively easy way to choose the right weight to help you reach your goals.

What Does Reps in Reserve (RIR) Mean?

Reps in Reserve (RIR) is rising in popularity as a method to measure the intensity of a lift by describing how many more repetitions you could perform before technical failure (an inability to perform the lift with good form). It’s best to employ this method after you’re comfortable with resistance training and have been familiarized with the scale.

Let’s say you’re doing a set of bench press and you do 10 reps. When you finish, you know that you could have done 2 more reps with good form before failing. Your Reps in Reserve (RIR) is 2 in this case, since you could have performed only 2 more repetitions with good form.

Calculating a percentage of your 1 Repetition Maximum (RM) to choose the load you need for your lift works, but the calculated load might be too heavy if you’re feeling less than your best, or it might even be too light on the days that you’re functioning at maximum capacity.

Using the RIR measurement will automatically adjust for your readiness to train, allowing you to still train at the desired intensity with good form. Additionally, if you don’t know your 1RM for an exercise, RIR can be particularly helpful in helping you nail down the appropriate weight for an exercise.

Reps in Reserve Chart: Example Workout

RIR can be the most useful in building muscular endurance, muscular development (hypertrophy), strength, or the max strength exercises in the power phase (Helms, et. al., 2016). Here is how RIR can be applied to Phases 2-5 of the OPT Model:

Phase of Training Repetitions Recommended RIR
Phase 2 Strength Endurance 8-12RM RIR 0-1
Phase 3 Muscular Development 6-12RM

RIR 0-2, Note: Train RIR 0 (to failure) only on the last set of a single-joint exercise

RIR 2-4 is best for multi-joint movements, and will avoid excessive muscle damage

Phase 4 Maximal Strength 1-5RM RIR 1-2, and occasionally, RIR 0
Phase 5 Power 1-5 reps for strength and 8-10 reps for power

RIR 2-3

RIR 4 (intensity cap to ensure adequate explosiveness in the movement)


Let’s apply it to a chest and triceps set in Phase 3 Muscular Development, employing the RIR method so that the intensity increases with each set:

Exercise Sets Reps RIR Tempo

Barbell Bench Press

Incline DB Chest Press

Triceps Rope Extension

     3       8

      Set 1: 4 RIR

      Set 2: 3 RIR

       Set 3: 2 RIR

   *For triceps, 0-1   RIR for the last set



There are many ways to apply RIR to reach your goals by simply staying within the above guidelines! You can keep the same RIR each set or manipulate it within the recommended range to vary your intensity level (making it harder or easier as you go).

Reps in Reserve Vs Training to Failure

We know that lifting close to failure is critical for muscular hypertrophy and strength development. Leaving some “reps in the tank” by employing the RIR method will accomplish this task without allowing you to go into failure each set.

It’s acceptable to train to failure every so often to reach a max strength goal, but training to failure often can cause changes in resting hormone concentrations and increases in strength may be compromised due to over training (Helms et. al., 2016).

How to Calculate Reps in Reserve

For new lifters, it can take some practice to properly gauge how many reps you have left “in the tank” before your form fails. You might practice a lift with a spotter and near the end, call out how many reps you think you have left, and see if you’re correct.

This can help teach you to gauge different intensity levels (4-6 RIR, 2 RIR, 1 RIR, etc.) and to know your personal limits. More experienced lifters will have a better feel for how many additional reps they could do once they finish their set, although they could use the same method to test their accuracy.

Can You Increase Your One-Rep Max with RIR Training?

According to the principle of specificity, the best way to increase your 1RM is to train at very heavy loads at low repetitions (aka to practice “maxing out”). RIR training can be a helpful guide when it comes to selecting the intensity required to achieve this goal.

To increase your 1RM, you’ll want to train in Phase 4, Maximal Strength Training. Using the guidelines listed above for recommended RIR usage in Phase 4, you’ll want to train in the 1-5 repetition range with an RIR of 1-2, and occasionally progressing to RIR 0 as you’re training to increase your one-rep max.

Here’s an example training plan for someone who wants to increase their 1RM of a lift over the course of 4 weeks:

Week 1: 5x5, 1-2 RIR
Week 2: 3x5, 1-2 RIR
Week 3 and 4: Use a Pyramid Set (example below)

Set 1: 5 reps 2 RIR
Set 2: 4 reps 2 RIR
Set 3: 3 reps 1-2 RIR
Set 4: 2 reps 1 RIR
Set 5: 1 rep 0 RIR

*Be sure to allow for 2-4 minutes of rest between each lift for each muscle group!

Is RIR Better for Hypertrophy or Strength Training?

RIR can be equally effective when applied to hypertrophy or strength training. The key is to train according to the rep ranges and intensity levels listed above according to your goals.

What is The Difference Between RIR and the RPE Scale?

The RPE, or Rate of Perceived Exertion, is a technique used to express how hard you feel like you are working during an exercise on a scale of 1-10, 1 being very easy and 10 being maximum effort. Similar to the RIR, it’s a method used to measure exercise intensity.

The difference is that the lifter reports how they feel (RPE) versus the number of repetitions they could still perform (RIR). Although the RPE measure was originally used for cardio workouts, it is also used to help lifters determine their intensity of effort.

Here’s a side by side of how the RPE scale and RIR matchup:

10 - Maximum Effort 0 Repetitions Remaining
9 - Very Hard 1 Repetitions Remaining
8 - Very Hard 2 Repetitions Remaining
7 - High, Vigorous 3 Repetitions Remaining
5-6 - Moderate to Somewhat Hard 4-6 Repetitions Remaining
3-4 - Light to Moderate

1-2 - Very Light -


These two methods can be used in tandem to help lifters gauge overall intensity, based upon the preference of the lifter. If you’re ready to ditch the calculator during strength training sessions, give the Reps in Reserve technique a try for a simple way to choose the right weight for your workout based on your goals.


Helms, E. R., Cronin, J., Storey, A., & Zourdos, M. C. (2016). Application of the Repetitions in Reserve-Based Rating of Perceived Exertion Scale for Resistance Training. Strength and conditioning journal, 38(4), 42–49.

The Author

Kinsey Mahaffey

Kinsey Mahaffey

Kinsey Mahaffey, MPH, is a Houston-based fitness educator, personal trainer and health coach who developed her commitment to lifelong fitness while playing Division I volleyball. She’s passionate about helping others cultivate a healthy lifestyle and enjoys educating other fitness professionals who share this vision. She’s a Master Instructor and Master Trainer for NASM. You can follow her on LinkedIn here.


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