Reps in Reserve (RIR) is a useful way to track fatigue over weeks by measuring how many repetitions you could still perform at the end of a set before reaching failure. Instead of pushing every set to complete exhaustion, leaving some reps in reserve helps monitor how fatigued your muscles are and how your strength fluctuates over time.
When you record RIR consistently, you get insight into your training intensity and recovery status. For example, if you usually finish a set with 2 reps left in the tank but over several weeks you find you only have 1 or 0 reps left, it indicates increasing fatigue or that the workout is becoming more challenging. Conversely, if you notice you have more reps in reserve than usual, it might mean you are recovering well or your strength has improved. This feedback allows you to adjust training loads or volume to avoid overtraining or undertraining.
Using RIR alongside other metrics like weight lifted and total reps helps create a clearer picture of your fatigue levels. It is especially helpful because strength can vary day to day due to factors like sleep, stress, or nutrition. By tracking RIR, you can auto-regulate your training intensity to match your current capacity, ensuring you push hard enough for progress but not so hard that you accumulate excessive fatigue.
Over weeks, monitoring RIR trends helps identify when you need to reduce training intensity or volume to recover, or when you can safely increase load for progressive overload. This approach supports long-term gains by balancing effort and recovery rather than relying solely on fixed percentages or maximal lifts.
In summary, Reps in Reserve is a practical tool to gauge fatigue by showing how close you are to failure each session. Tracking it over time reveals patterns in your readiness and recovery, enabling smarter adjustments to your training plan.
Sources
https://www.verrotraining.com/blog/maximize-your-training-accuracy-the-verro-e1rm-formula
https://rippedbody.com/rpe/
https://www.jefit.com/wp/general-fitness/break-through-strength-plateaus-jefit-guide/
