Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: A systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of intervention trials
PubMed 33497853 · doi:10.1016/j.jshs.2021.01.007
What was done
Authors conducted a systematic review and meta-analysis evaluating the effects of resistance training to repetition failure versus non-failure on muscular strength and muscle hypertrophy. Subgroup meta-analyses assessed potential moderators: training status (trained vs. untrained), volume equation (equated vs. non-equated), body region (upper vs. lower), exercise selection (multi- vs. single-joint for strength), and study design (independent vs. dependent groups).
What was found
Fifteen studies were analyzed, all in young adults. Overall meta-analysis showed no significant difference between failure and non-failure for muscular strength (ES = -0.09, 95% CI: -0.22 to 0.05) or hypertrophy (ES = 0.22, 95% CI: -0.11 to 0.55). Subgroup analyses by body region, exercise selection, or study design showed no significant differences. When training volume was not equated, non-failure significantly favored strength gains (ES = -0.32, 95% CI: -0.57 to -0.07). In resistance-trained individuals, training to failure showed a significant positive effect for muscle hypertrophy (ES = 0.15, 95% CI: 0.03 to 0.26).
Why it matters
This review demonstrates that lifting to failure is not necessary for maximizing strength or size, allowing trainees to avoid unnecessary fatigue unless pursuing marginal hypertrophy gains in trained states.
Limits
All included studies were limited to young adults, leaving older adults and highly trained or elite athletes unrepresented. Total subject count, specific exercise loads, proximity to failure in non-failure groups, and long-term adherence effects were not detailed in the abstract.
Cited by
- supports Emerging scientific evidence indicates that leaving one or two repetitions in reserve achieves comparable muscle hypertrophy and strength gains to training sets to failure.