Training to muscular failure increases recovery time compared to non-failure protocols when total training volume is matched.

Study: Influence of Resistance Training Proximity-to-Failure, Determined by Repetitions-in-Reserve, on Neuromuscular Fatigue in Resistance-Trained Males and Females

When people lift weights until they can't do another rep, their muscles take longer to bounce back than when they stop a few reps short—even if they do the same total amount of lifting. The study found people felt stronger again faster when they didn’t push to complete failure.

Study: Time course of recovery following resistance training leading or not to failure

When people lift weights until they can't do another rep, their muscles take longer to recover than when they stop just before exhaustion—even if they do the same total number of reps. This study proved it by testing both methods and seeing that failure made people slower to bounce back.

Study: Acute Effects of High-Load Training to Failure vs. Non-Failure on Posture and Core Endurance in Collegiate Weightlifters: A Crossover Study

When people lift weights until they can't do another rep, their body gets more tired and their posture gets worse afterward than when they stop before reaching failure—even if they do the same total amount of lifting. This means their body needs more time to recover.

Study: Acute fatigue and recovery responses to resistance training performed to momentary muscular failure: an exploratory multimodal physiological study.

When people lift weights until they can't do another rep, their muscles take longer to recover than when they stop before failure—even if they do the same total amount of lifting. The study found more soreness, stress, and slower strength recovery after going to failure.