Acute Fatigue and Chronic Adaptations with Set-Termination and Intra-Set Rest Strategies in Resistance Training: An Umbrella Review

This umbrella review examined acute fatigue and chronic adaptation with non-failure versus failure and cluster sets or rest redistribution versus traditional sets. Velocity-loss thresholds formed a supplementary branch. Seven databases were searched, most recently on 17 September 2026. Eligible systematic reviews addressed direct comparisons in healthy adults; main chronic evidence required at least six weeks. The synthesis considered methodological confidence, target-study overlap and evidence-unit eligibility. Joint interpretation required corresponding comparators, populations, loads, volumes and rest structures. Thirty-three reviews were included: 30 had critically low and 3 low methodological confidence. Ten supplied 69 quantitative and 16 narrative evidence units for the main synthesis, including dependent estimates. Selected post-exercise neuromuscular and perceived-exertion estimates favoured non-failure. Intra-set rest findings varied across within-session measures. Chronic findings depended on the outcome and prescription. Selected hypertrophy estimates favoured failure or, in trained men with unequal achieved volume, higher velocity loss; preserved adaptation was not established. None of the 13 selected, non-exhaustive combinations assembled during extraction supported a joint interpretation. This finding applies only to those combinations, not all potential acute–chronic comparisons. Training decisions remain conditional on the studied populations, prescriptions and outcomes. No external funding was received; the review was not prospectively registered.