Reps in Reserve (RIR) is a concept used to gauge how many repetitions you could still perform before reaching muscle failure during a set. When learning new movements, using RIR can be quite useful because it helps manage effort and fatigue while maintaining good technique. Instead of pushing to complete failure, leaving some reps in reserve allows you to focus on form and control, which is crucial when mastering unfamiliar exercises.
For beginners or when trying new movements, aiming for an RIR of about 1 to 3 reps—meaning you stop a set when you feel you could still do one to three more reps—helps prevent excessive fatigue and reduces the risk of injury. This approach encourages consistent practice without overloading the muscles or nervous system too early, which can hinder skill acquisition and recovery. It also allows you to build confidence in the movement pattern before increasing intensity.
Training to failure can cause more fatigue and longer recovery times, which might slow down progress, especially for novices still learning proper technique. By using RIR, you can train hard enough to stimulate adaptation but still keep enough energy and focus to perform subsequent sets or sessions effectively. This balance is important because it supports both strength gains and motor learning.
Moreover, RIR is linked to the Rating of Perceived Exertion (RPE) scale, where an RPE of 8 to 9 corresponds roughly to leaving 1 to 2 reps in reserve. This intensity range is often recommended for compound exercises when learning new movements, as it provides a good stimulus without excessive strain. Isolation exercises or machine work can sometimes be taken closer to failure safely, but for complex new movements, maintaining some reps in reserve is safer and more productive.
In summary, using reps in reserve when learning new movements helps you train effectively by managing fatigue, protecting technique, and allowing for better recovery. It encourages a sustainable training pace that supports both skill development and strength improvements.
Sources
https://rippedbody.com/rpe/
https://www.mensjournal.com/health-fitness/what-is-escalating-density-training
https://www.minimumviablepump.com/guides/myo-reps
https://www.youtube.com/watch?v=2S4LwKoKMY0&vl=te
https://www.womenshealthmag.com/uk/fitness/strength-training/a69105961/two-30-minute-workouts-build-strength-study/
