Reps in Reserve (RIR) is a training concept that refers to how many repetitions you could still perform before reaching muscular failure during an exercise set. For example, if you stop a set at eight reps but could have done ten, you have two reps in reserve. This method helps athletes and lifters gauge their effort without always pushing to absolute failure.
Using RIR in training supports sustainability by managing fatigue and recovery better. Training to failure on every set can cause excessive fatigue, which may reduce the frequency and quality of future workouts. By leaving a few reps in reserve, you reduce the risk of overtraining and injury, allowing for more consistent progress over time. Research shows that training close to failure but not all the way can produce similar muscle growth and strength gains while improving recovery status[2][3].
RIR also helps lifters develop better self-awareness of their limits. Studies indicate that people can accurately estimate how many reps they have left, especially as they become more experienced. This accuracy allows for safer training by avoiding pushing beyond technical failure, which can compromise form and increase injury risk[3].
In practice, a common recommendation is to leave 1 to 3 reps in reserve on compound lifts, which are more demanding, and only push to failure on the last set of isolation exercises. This approach balances intensity with recovery, enabling athletes to train harder over the long term without burnout[2].
While some traditional bodybuilders, like Dorian Yates, advocate training to failure for maximum intensity, modern evidence supports that RIR-based training can be equally effective and more sustainable for most people[1][2].
Sources
https://www.menshealth.com/uk/building-muscle/a69216657/dorian-yates-reps-in-reserve/
https://rippedbody.com/rpe/
https://www.empower.physio/blog-all/rpe-vs-rir-1
https://www.minimumviablepump.com/guides/rir
