Reps in Reserve (RIR) is a useful concept that can help manage fatigue while still promoting progressive overload in training. RIR refers to how many more repetitions you could perform at the end of a set before reaching failure. For example, if you finish a set and feel you could do two more reps, you have 2 reps in reserve. Using RIR allows you to push hard enough to stimulate muscle growth and strength gains without going to complete failure every time, which can cause excessive fatigue and slow recovery.
When applying progressive overload, the goal is to gradually increase training stress over time by adding weight, reps, sets, or other variables. Training with a certain number of reps in reserve helps control fatigue so you can consistently increase these variables without burning out. For instance, stopping a set with 1 to 3 reps in reserve means you are working near your maximum effort but not fully exhausting yourself. This approach lets you maintain good form and recover better between sessions, enabling more frequent and effective training.
Research shows that training to failure is not necessary for muscle growth and can even hinder progress due to increased fatigue. Instead, leaving some reps in reserve can produce similar strength and hypertrophy gains while allowing you to train more consistently. This balance helps you progressively overload by either increasing the weight lifted or the number of reps performed over time, without risking injury or overtraining.
In practice, you might start a training block aiming for about 2 reps in reserve on your working sets. As you adapt, you can increase the load or reps while maintaining that RIR range. This method ensures you are pushing your muscles enough to cause adaptation but not so much that recovery suffers. It also allows you to adjust training intensity based on how you feel day-to-day, making your progression smarter and more sustainable.
In summary, reps in reserve help with progressive overload by providing a way to gauge effort and manage fatigue. This enables steady increases in training stress through weight or reps, supporting muscle growth and strength gains while reducing the risk of burnout.
Sources
https://www.youtube.com/watch?v=CqwNheb8epM
https://www.myjuniper.com/blog/what-is-progressive-overload
https://rippedbody.com/rpe/
https://www.jefit.com/wp/guide/the-science-behind-why-progressive-overload-builds-strength-and-muscle/
