Reps in Reserve (RIR) is a concept that refers to how many repetitions you could still perform at the end of a set before reaching failure. It plays a crucial role in progressing over time because it helps balance training intensity and recovery. Instead of always pushing to failure, leaving 1 to 3 reps in reserve allows you to train hard enough to stimulate muscle growth and strength gains while managing fatigue effectively.
Training with some reps left in the tank helps you avoid excessive fatigue that can impair recovery and reduce your ability to train frequently. Research shows that training to failure does not necessarily produce better results than stopping just short of failure, but it does increase fatigue and recovery time. By using RIR, you can maintain higher training frequencies and overall volume, which are important for long-term progress. For example, leaving 1-2 reps in reserve on compound lifts and only occasionally training to failure on isolation exercises can optimize gains and reduce injury risk.
Additionally, RIR helps you adjust your training intensity based on daily performance fluctuations. On days when you feel strong, you can push closer to failure, and on days when you feel weaker, you can back off slightly without losing progress. This autoregulation ensures consistent effort over time, which is key for steady improvement.
In summary, reps in reserve is important because it allows you to train intensely enough to promote adaptation while managing fatigue and recovery. This balance supports sustainable progression in strength and muscle growth over the long term.
Sources
https://rippedbody.com/rpe/
https://betterme.world/articles/building-a-workout-plan/amp/
https://www.menshealth.com/uk/building-muscle/a28433729/full-body-workouts/
