Reps in Reserve, or RIR, is a simple way to know how hard you are working during a set. It means the number of extra reps you think you could do if you pushed yourself. For example, if you stop a set feeling like you could do two more reps, that’s 2 RIR. If you stop when you feel you could do four more, that’s 4 RIR. This idea helps you stay in control of your effort, especially when you switch exercises.
When you change exercises, your body responds differently. Some movements are harder on your joints and nervous system, like squats or deadlifts. Others, like machine presses or cable rows, are easier to recover from. Using RIR helps you adjust your effort based on the exercise. For heavy, complex lifts, it’s smart to leave more reps in reserve, like 2 or 3. This keeps you fresh and lowers the risk of injury. For lighter, isolation moves, you can go closer to failure, maybe 1 or 2 RIR, since these don’t cause as much fatigue.
RIR also helps you manage fatigue when you switch between different types of workouts. If you do a lot of compound lifts one day, you can use higher RIR to stay safe. On days with more isolation or machine work, you can lower your RIR and push a bit harder. This way, you get the most out of each exercise without burning out or getting hurt.
Another benefit is that RIR lets you listen to your body. Some days you feel strong, other days you feel tired. By paying attention to how many reps you have left, you can adjust your weight or reps to match your energy. This is especially useful when you try new exercises or change your routine. You don’t have to guess how hard to go. Just check how many reps you think you could do and use that to guide your effort.
RIR also helps you build muscle and strength over time. Training close to failure sometimes is good for growth, but doing it all the time can make you tired and slow your progress. By using RIR, you can balance hard sets with easier ones, so you keep making gains without overdoing it. This is important when you switch exercises, because each one puts stress on your body in a different way.
Sources
https://rippedbody.com/rpe/
https://www.getlabtest.com/news/post/reps-meaning-strength-training
https://www.menshealth.com/uk/building-muscle/train-smarter/a69163138/back-off-sets/
https://www.performancelab.com/blogs/fitness/transform-muscle-strength-and-size-with-the-3-7-method
https://www.muscleandfitness.com/workouts/workout-tips/why-fst-7-can-be-a-top-training-method-for-making-massive-gains/
https://betterme.world/articles/calisthenics-daily-workout-plan/
https://www.elevaterope.com/blogs/articles/rate-of-perceived-exertion
https://www.menshealth.com/uk/building-muscle/a69163130/vince-girondas-8×8-system-iron-guru/
https://www.womenshealthmag.com/uk/fitness/strength-training/a69105961/two-30-minute-workouts-build-strength-study/
