So, what is it?
If you’ve ever completed a set and thought, “I probably had two more reps in the tank,” that’s RIR in a nutshell. The concept is solid: Instead of treating every set like an all-out war, stop a few reps short and use the reps left in the tank to manage fatigue, volume, and long-term gains.
But the problem arises when it is left open to interpretation.
Some lifters use RIR as an auto-regulation tool, while others treat it as a comfort blanket, convincing themselves that they are training hard when they are away from it.
Here we attempt to explain what RIR is, why some and others defend it, why critics dismiss it, and, most importantly, whether RIR helps or hurts your bottom line.
RIR origin
Reps in Reserve (RIR) emerged from exercise science research in the early 2000s, specifically from studies on the assessment of perceived exertion (RPE). Popular in endurance sports, RPE was adapted to strength training to measure how hard a set felt based on the number of reps you had left in the tank.
RIR, a strength-specific spin-off from RPE, was refined and popularized by evidence-based training leaders such as Dr. Mike Tuchscherer and later Dr. Mike Israetel. Israel’s vision went viral because it blended periodization, hypertrophy science, and autoregulation: the idea that you can adjust exercise intensity based on how your body feels and performs, rather than chasing numbers.
But what started out as a self-regulation tool for intermediate to advanced lifters somehow became shorthand for “don’t train too hard” on social media, especially when it came to more inexperienced lifters. Many influencers started preaching RIR as gospel without explaining how to measure it or when to use it. As expected, the reaction followed.
In short: the concept was solid. The execution? Things haven’t always gone as planned.
What are Reps in Reserve (RIR) in strength training?
Reps in Reserve is a self-assessment tool that estimates how many quality reps you can do in a set before a technical failure occurs. Technical failure occurs when you cannot perform another full movement repetition with good form. So if you’re doing 225 reps and you feel like you have two reps left in the tank, that’s RIR 2. It’s a way to automatically regulate effort based on how you’re feeling that day – useful when you’re juggling stress, sleep and recovery. RIR helps control fatigue and ensures that you still train with sufficient intensity.
This is what RIR should not be used for
- RIR doesn’t mean you have to quit just because it’s hard.
- It’s not a license never to grind.
- And it is certainly not a substitute for effort.
If you say a set was RIR 2, but you could have done 5 more reps… then you are misjudging your effort and not using RIR. It works best if you are honest with yourself and have put in enough time to feel the difference between hard work and near failure.
How to use RIR correctly without wiping out your profits
Reps in Reserve, when used correctly, will balance your gains and post-workout recovery. It lets you flirt with failure without crashing into it, which helps with progress, recovery, and longevity. But using RIR requires self-awareness, effort and honesty. Yes, it will take some time if you’re new to it and you need to know what lifting to failure feels like before you decide if you have a few more reps in the tank.
Experience is your greatest teacher here. To make this practical, here’s a visual guide:
How to apply RIR
| Sample RIR guide | |||
|---|---|---|---|
| Goal | Exercise type | RIR target | Why |
| Maximum strength | Composite lifts | 1-2 RIR | Maintains rod speed and shape under heavy loads without grinding |
| Hypertrophy (size gain) | Connection and insulation | 0-2 RIR | Tension + Proximity to failure creates a stimulus for growth |
| Muscular endurance | High repetition movements | 1-3 RIR | Maintains shape and manages fatigue |
| Skill/technique work | Olympia lifts, complex movements | 3-4 RIR | Prioritizes movement quality over effort |
What science actually says about RIR and profit
RIR is a reliable tax recommendation tool
A study published in the Journal of strength and conditioning research found that RIR is a reliable method for recommending loads for exercises such as deadlift and bench press. When trained lifters use RIR consistently, it matches actual intensity, making it useful for autoregulatory training.
RIR reflects how close you are to failure
Research on RPE scales coupled with RIR shows that lifters’ subjective estimates of how many reps they have left correspond to meaningful differences in training intensity, especially as lifters gain experience with the system.
RIR accuracy improves with experience
One criticism of RIR is that lifters cannot judge how many reps they have left. The evidence is mixed but promising: experienced lifters tend to be fairly accurate in estimating RIR, especially near failure, while beginners tend to be conservative.
Proximity to failure and profit
Several studies have examined how close to failure you train, the core of RIR, and how this affects muscle and strength: an intervention comparing sets performed to failure with sets held back by a few reps found that muscle size and strength gains were similar when training to failure. This study suggests that it is not necessary to perform each set completely to make a profit. Research manipulating RIR zones (e.g., 1–3 RIR vs. 4–6 RIR) found similar strength gains between zones and similar gains when training to actual failure. This study supports the idea that quitting for the sake of failure can maintain growth while reducing extreme fatigue. A dose-response view points toward more growth as sets get closer to failure, but researchers still haven’t established the exact relationship between RIR and hypertrophy
So why is RIR under scrutiny?
Why some lifters say RIR is ‘lazy training’
Representatives in the reserve are not under fire because it doesn’t work; they are under fire because it is sometimes misinterpreted and treated as a license to slow down. Here’s what the naysayers have to say.
RIR turns into ‘lazy training’
Some coaches claim that RIR encourages undertraining. The logic? If you always leave 3-4 reps in the tank, you may never reach the effort threshold needed to make gains, especially if you’re not honest with yourself. Critics like Jeff Nippard have warned that too much RIR can lead to sandbagging. This way of thinking has led to the opposite extreme: “Just fail every time and forget the numbers.” But that creates its own problems: burnout, poor recovery and stagnation.
Where the confusion exists
Recently, Dr. Mike Israetel, a longtime proponent of RIR-based training, helped popularize this system by giving lifters a framework to regulate intensity across training blocks. But now even some experts, followers and content creators have questioned how rigid or over-intellectual the RIR method has become when practiced by less experienced lifters.
His approach has been successful for many RP Strength users and RIR proponents. The other side of the argument emerges when it comes to less experienced lifters.
- I don’t know what failure actually feels like
- Overestimate how hard you push
- Stay in a high RIR zone forever and call it “smart training.”
Some coaches now argue that lifters should learn RIR only after they have developed a solid kinesthetic sense of actual failure, and not before. This argument makes a lot of sense.
N1 vs RP
Cassem Hanson from N1 Trainingwho has challenged Israel and RP’s hypertrophy approach in recent months. The feud has sparked controversy on YouTube, Instagram and podcasts.
Kassem states that:
- RIR and volume targets are overestimated without proper training selection
- Lifting form, joint angles and biomechanics are more important than chasing reps and proximity to failure
- Many lifters who follow the RIR templates don’t know how to contract muscles or control tempo, so the effort metric becomes meaningless
This collision has revived a larger discussion in the lifting world:
What is more important: data or context? Science or execution? Templates or customized coaching? Neither side is wrong, but this debate is a reminder: frameworks are not infallible, and coaching nuance trumps spreadsheets.
In short, for men focused on strength, recovery and longevity
Reps in reserve is a legitimate, science-based method to measure effort and manage fatigue without grinding yourself into dust. It’s not perfect, and it’s not for everyone, but it’s far from it
useless. What kills profits isn’t RIR; it’s not training hard enough while pretending to do so.
RIR’s biggest critics have often not tried, misinterpreted, or abused it. If your idea of “leaving three reps in the tank” means stopping when your biceps tingle, you’re missing the point. Before you slam RIR, try it first.
Train hard. Recover smartly and don’t be afraid to try before you throw it aside.
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