Effects of Resistance Training Performed to Failure or Not to Failure on Muscle Strength, Hypertrophy, and Power Output: A Systematic Review With Meta-Analysis.
Level 2 - randomized trial
Systematic review including both randomized and nonrandomized longitudinal studies
PubMed 33555822 · doi:10.1519/JSC.0000000000003936
What was done
A systematic review and meta-analysis of longitudinal studies (intervention duration ≥6 weeks) comparing resistance training to failure (RTF) versus not to failure (RTNF) on maximal strength, muscle hypertrophy, and muscle power in adults across 3 electronic databases. Both randomized and nonrandomized studies were eligible. Pooled effects were calculated as standardized mean differences (SMDs) with 95% confidence intervals using random-effects models.
What was found
Thirteen studies were included: - Maximal strength: No overall difference between RTF and RTNF (SMD: -0.08, p = 0.642); RTNF showed greater strength gains when volumes were not equalized (SMD: -0.34, p = 0.048). - Muscle hypertrophy: RTF showed greater hypertrophy in the overall analysis (SMD: 0.75, p = 0.005), but no difference was found when training volumes were equalized. - Muscle power: No overall difference was found (SMD: -0.20, p = 0.239); RTNF yielded greater power improvements when training volumes were not equalized (SMD: -0.61, p = 0.025).
Why it matters
This review demonstrates that lifting to failure is not mandatory to optimize strength, power, or hypertrophy. When total training volume is equated, non-failure and failure training produce comparable hypertrophy, while non-failure training may better support strength and power when volume differs.
Limits
The analysis included only 13 studies and mixed nonrandomized with randomized designs. The abstract does not report the total participant sample size, subject characteristics (age, sex, training status), or exact 95% confidence intervals.
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.