How Closely Should You Follow Reps in Reserve in Your Workouts
When you’re lifting weights, one of the most common questions is how hard you should push each set. Should you go all out until you can’t do another rep? Should you stop early? The answer lies in understanding reps in reserve, or RIR, which is a simple but powerful concept that can transform how you train.
Reps in reserve simply means the number of repetitions you could theoretically do with good form before reaching complete failure. If you finish a set and feel like you could have done two more reps, you stopped with two reps in reserve. This concept matters because it directly affects your recovery, your ability to train consistently, and ultimately, your results.
The traditional approach to weight training often involves pushing every set to failure or near failure. Many lifters believe that going all out is the only way to build muscle and strength. However, research shows this isn’t necessarily true. Training to failure and training with reps left in the tank produce similar muscle-building adaptations. The key difference is that training to failure leaves you in a more fatigued state, which can hurt your recovery and your ability to train hard in future sessions.
Think about it this way. If you exhaust yourself completely in your first workout of the week, you’ll feel beaten down going into your second session. You won’t be as strong, you won’t be able to lift as much weight, and you’ll accumulate more fatigue without getting proportionally better results. By contrast, if you manage your fatigue smartly, you’ll walk into every session feeling fresh and ready to perform at your best.
The practical recommendation is to aim for one to two reps in reserve on most of your sets. This means stopping when you feel like you could do one or two more reps with good form. For compound exercises like squats, deadlifts, and bench presses, this approach is especially valuable because these movements demand a lot from your nervous system and joints. Leaving reps in reserve helps you manage the overall stress on your body.
There’s an exception to this rule. On the final set of isolation exercises for each muscle group, you can take that set closer to failure. Isolation exercises like leg curls, bicep curls, or cable flyes are lower risk and don’t tax your nervous system as heavily. Taking the last set of these movements to failure or near failure can provide additional stimulus without compromising your recovery or your ability to train hard in future sessions.
RPE, or rate of perceived exertion, works hand in hand with reps in reserve. RPE is a scale from one to ten that describes how hard a set feels. An RPE of nine means you could do one more rep, while an RPE of eight means you could do two more reps. Using RPE allows you to adjust your training based on how you feel on any given day. Some days you’ll feel stronger than expected after your warm-ups, and you can push a bit harder. Other days you’ll feel weaker, and you can dial it back. This flexibility is crucial because it prevents you from overtraining on bad days and allows you to capitalize on good days.
The data on this is clear. When lifters train with an RPE of nine on their first set, they actually perform more total reps across all their sets compared to training to failure. In one comparison, training to failure resulted in 22 total reps across three sets, while training with an RPE of nine resulted in 26 total reps. This happens because you’re fresher on subsequent sets when you don’t completely exhaust yourself on the first set. More total reps means more volume, which is one of the primary drivers of muscle growth.
Following reps in reserve closely doesn’t mean being lazy or not working hard. It means being strategic about your effort. You’re still lifting heavy weights, you’re still creating significant stimulus for muscle growth and strength gains, but you’re doing it in a way that allows you to recover better and train more frequently. Frequency matters because you can hit each muscle group more often when you’re not completely wrecked after every session.
The intensity of your training should still match your goals. If you’re training for strength, you’ll use heavier weights with lower reps, typically three to six reps per set. If you’re training for muscle growth, you’ll use moderate to heavy weights with moderate reps, typically six to twelve reps per set. If you’re training for endurance, you’ll use lighter weights with higher reps, typically fifteen to twenty or more reps per set. Regardless of your goal, the principle of leaving one to two reps in reserve applies.
One important note is that reps in reserve is somewhat subjective. It requires you to develop body awareness and understand your own capabilities. Over time, as you train consistently, you’ll get better at judging how many reps you have left in the tank. You’ll learn the difference between a set where you could do one more rep versus two more reps. This skill develops naturally through experience.
The bottom line is that you should follow reps in reserve fairly closely, especially on compound movements. Aim for one to two reps in reserve on most sets, take your final isolation set closer to failure if you want, and use RPE to adjust based on how you feel. This approach will help you train hard, recover well, and make consistent progress over time. You don’t need to go to complete failure on every set to build muscle and strength. In fact, doing so will likely slow your progress because you’ll be too fatigued to train optimally in future sessions.
Sources
https://www.mensjournal.com/health-fitness/what-is-escalating-density-training
