Reps in Reserve (RIR) is a training concept where you stop a set before reaching complete muscle failure, leaving a certain number of reps “in reserve.” This approach can be very useful during strength plateaus because it helps manage fatigue and recovery while still providing enough stimulus for progress.
When lifters hit a strength plateau, pushing every set to failure can lead to excessive fatigue, longer recovery times, and increased risk of injury. Using RIR allows you to train hard but avoid the extreme stress of failure sets. For example, stopping a set with 1-3 reps left in the tank means you maintain high intensity without overtaxing your nervous system. This can help you train more consistently and frequently, which is important for breaking through plateaus[2].
Research shows that training to failure does not necessarily produce better strength or muscle gains compared to stopping short of failure. In fact, training with some reps in reserve often results in more total reps performed across sets and better recovery, which supports long-term progress[2]. This means you can maintain or even increase training volume without the downsides of constant maximal effort.
Additionally, RIR can be combined with strategies like back-off sets, where you perform a heavy top set followed by lighter sets with more reps. This method balances intensity and volume, reducing joint stress and nervous system fatigue while still promoting strength and hypertrophy gains[3].
Using RIR also helps with autoregulation—adjusting your training intensity based on how you feel that day. Since strength can fluctuate due to factors like sleep, nutrition, and stress, leaving reps in reserve lets you train effectively even on lower-energy days without risking burnout[2][4].
In summary, reps in reserve is a practical tool during strength plateaus because it manages fatigue, supports recovery, and allows for consistent training intensity. It helps lifters avoid the pitfalls of training to failure while still pushing progress forward.
Sources
https://www.si.com/everyday-athlete/training/unlock-maximum-muscle-growth-why-all-rep-ranges-work-and-how-to-use-them
https://rippedbody.com/rpe/
https://www.menshealth.com/uk/building-muscle/train-smarter/a69163138/back-off-sets/
https://www.womenshealthmag.com/uk/fitness/strength-training/a69435676/how-many-reps-should-you-do-for-results/
