Reps in Reserve and Real Strength: How They Connect
When you’re lifting weights, you might hear coaches talk about “reps in reserve” or RIR. This concept has become increasingly popular in strength training circles, but many lifters wonder if it actually reflects how strong they really are. Understanding this relationship requires looking at what reps in reserve means and how it compares to actual maximum strength measurements.
What Reps in Reserve Actually Means
Reps in reserve refers to how many additional repetitions you could theoretically perform before reaching complete muscular failure. If you’re doing a set of squats and you stop when you feel you could do two more reps, you have two reps in reserve. This differs from training to failure, where you push until you cannot complete another repetition with proper form.
The concept sounds straightforward, but measuring it accurately is where things get tricky. Your perception of how many reps you have left might not always match reality. Research shows that people can improve at estimating their reps in reserve over time, but this skill takes practice and self-awareness.[5]
How Reps in Reserve Relates to Maximum Strength
Your one-repetition maximum, or 1RM, represents the heaviest weight you can lift for a single repetition with proper form.[1] This is considered the gold standard measurement of raw strength. Reps in reserve, on the other hand, is more of a training strategy than a strength measurement.
The connection between them exists but isn’t direct. When you know your 1RM, you can calculate appropriate training loads. For example, the 3/7 method uses approximately 70 percent of your 1RM as the working weight.[2] At this load, you’re not testing your maximum strength but rather using a submaximal weight to build strength and muscle over time.
The Accuracy Question
One important finding from recent research involves how well people can judge their reps in reserve. A study examining 30-minute workouts found that participants improved their ability to accurately estimate how many reps they had remaining before failure, particularly when doing bench press exercises.[5] This suggests that reps in reserve becomes a more reliable indicator of your actual capacity the more experienced you become as a lifter.
However, reps in reserve is still an estimate rather than a precise measurement. Your perception can be influenced by fatigue, how well you slept, your nutrition, and even your mental state on a given day. Someone might feel like they have two reps in reserve when they actually have three, or vice versa.
Training to Failure Versus Reps in Reserve
Research comparing these two approaches reveals interesting differences. When participants trained to complete muscular failure, they saw slightly more muscle growth and increases in power compared to those who stopped with reps in reserve.[5] This suggests that stopping short of failure might not fully tap into your strength potential on that particular set.
Yet stopping with reps in reserve offers practical advantages. It reduces injury risk, allows for better recovery between sets, and can be sustained over longer training periods without burning out. For building strength over weeks and months, reps in reserve might actually be the smarter choice even if it doesn’t maximize single-session performance.
What the Research Shows About Strength Gains
Studies examining different training protocols show that you can build significant strength without always pushing to failure. The 3/7 method, which uses moderate loads and controlled rep ranges, produced 1RM improvements of nearly 30 percent in some studies.[2] This happened despite participants not training to absolute failure on every set.
This suggests that reps in reserve doesn’t prevent strength development. Instead, it appears to be a tool for managing fatigue while still creating enough stimulus for adaptation. Your actual strength gains depend more on consistent training, progressive overload, and proper recovery than on whether you squeeze out those final reps.
Experience Level Matters
Your training experience significantly affects how well reps in reserve correlates with real strength. Beginners often misjudge their capacity because they’re still learning movement patterns and haven’t developed the body awareness that comes with experience.[3] An intermediate or advanced lifter typically has a better sense of their true capabilities and can more accurately gauge reps in reserve.
For beginners, starting with simple protocols like three sets of twelve repetitions using bodyweight or light weights provides a safer foundation.[3] As you progress and gain experience, you can use reps in reserve more strategically as part of your training approach.
The Practical Application
Understanding reps in reserve doesn’t replace knowing your actual 1RM. If you want to know your true maximum strength, you need to test it directly or use validated formulas to estimate it from submaximal lifts.[1] Reps in reserve is better viewed as a training tool that helps you manage intensity and volume while building toward greater strength.
Many strength coaches recommend using reps in reserve for most training sessions while occasionally testing your actual maximum to see how your training is translating to real strength gains. This balanced approach gives you the safety and sustainability benefits of reps in reserve while still tracking your actual progress through measurable strength improvements.
The Bottom Line on Matching Real Strength
Reps in reserve can reasonably reflect your strength capacity, but it’s not a perfect measurement. It works better as you gain experience and learn to read your body accurately. Your perception of reps in reserve will generally improve with training age, making it increasingly reliable as an indicator of your true strength levels. However, for precise strength assessment, direct testing or validated estimation formulas remain the most accurate approach.
Sources
https://www.topendsports.com/testing/tests/1rm.htm
https://www.performancelab.com/blogs/fitness/transform-muscle-strength-and-size-with-the-3-7-method
