Reps in Reserve (RIR) is a training concept where you stop a set before reaching complete muscle failure, leaving a few repetitions “in reserve.” This approach helps manage joint fatigue by reducing the stress placed on joints during resistance training while still effectively stimulating muscles.
When you train with RIR, you avoid pushing your joints to their absolute limit. Instead of grinding out every last rep, you stop 1 to 2 reps short of failure. This allows you to recruit most muscle fibers needed for growth without overloading the joints excessively. By not going to failure every set, the cumulative joint stress is lowered, which can reduce inflammation and discomfort over time. This is especially important for compound lifts that involve multiple joints, such as squats or bench presses, where joint fatigue can accumulate quickly[1].
Using RIR also helps maintain better lifting form because fatigue often leads to poor technique, which increases the risk of joint injury. When you stop before failure, you can keep control and alignment throughout the set, protecting your joints from unnecessary strain.
Additionally, RIR allows for more consistent training volume and frequency. Since joint fatigue is managed better, you can train more often or with higher total volume without overloading your joints. This balance supports muscle growth while preserving joint health[1].
In summary, reps in reserve help manage joint fatigue by limiting the intensity to a level that still challenges muscles but spares joints from excessive stress. This approach promotes safer, more sustainable training and can improve long-term joint function.
Sources
https://erickimphotography.com/maximum-muscle-growth-the-ultimate-battle-plan/
https://www.si.com/everyday-athlete/training/unlock-maximum-muscle-growth-why-all-rep-ranges-work-and-how-to-use-them
https://www.menshealth.com/uk/building-muscle/train-smarter/a69163138/back-off-sets/
