Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: a systematic review and meta-analysis
Grgic J, et al.
Evidence is still building up
Summary
A systematic review and meta-analysis of 15 studies comparing resistance training performed to repetition failure against non-failure training. All participants were young adults. The pooled analyses found no significant difference between conditions for muscular strength (effect size -0.09, 95% CI -0.22 to 0.05) or hypertrophy (0.22, 95% CI -0.11 to 0.55), and subgroup analyses by body region, exercise selection or study design showed no differences either. In studies that did not equate training volume, however, the analysis significantly favoured non-failure training for strength (-0.32, 95% CI -0.57 to -0.07); and in resistance-trained individuals specifically, training to failure showed a significant effect for hypertrophy (0.15, 95% CI 0.03-0.26). The authors conclude that training to muscle failure does not seem to be required for gains in strength and muscle size, but does not seem to have detrimental effects either, and that more studies among older adults and highly trained individuals are needed.
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Key findings
- 1
Pooled analyses found no significant difference for strength (-0.09, 95% CI -0.22 to 0.05) or hypertrophy (0.22, 95% CI -0.11 to 0.55).
- 2
In studies that did not equate training volume, the analysis significantly favoured non-failure training for strength (-0.32, 95% CI -0.57 to -0.07).
- 3
In resistance-trained individuals, training to failure showed a significant effect for hypertrophy (0.15, 95% CI 0.03-0.26).
- 4
Subgroup analyses by body region, exercise selection and study design showed no significant differences between conditions.
- 5
All participants were young adults; the authors call for more studies among older adults and highly trained individuals.
- 6
The abstract addresses neither reps-in-reserve as a measure nor injury, fatigue or muscle damage markers.
Articles featuring this study
- Research vs Bro-science
Weekly and per-exercise sets: what our sources can and cannot say
"Lifting heavy is the key to muscle growth" vs. "what matters is accumulating enough total volume" — this has been debated endlessly in training communities. All three sources we hold concern sets per week or per exercise, or training to failure. We hold no study of intensity (%1RM), so we cannot rank intensity against volume. We set out what our sources report about sets. Both sources we hold (Schoenfeld 2017, Krieger 2010) concern sets, yet we drew conclusions comparing them against intensity (%1RM). We hold no study of intensity, and have withdrawn everything ranking the two. We also misattributed the failure meta-analysis to Schoenfeld; its first author is Grgic, and we have corrected it.
Shingo Yoshizaki
- Research vs Bro-science
Do You Really Need to Train to Failure to Build Muscle? Common Belief vs. Research
"The last rep that breaks your limits is when muscles grow" — this mantra drives many gym-goers to push to failure every single set. All three sources we hold compare training to muscle failure against non-failure training. None uses reps in reserve as a measure, and none assessed injury or overtraining. We set out what they report about strength and hypertrophy. We have withdrawn everything about RIR as a measure, the mechanism of the hypertrophic signal, damage markers, fatigue, injury risk and recovery cost. None of our three sources (Schoenfeld and Grgic 2019, Grgic et al. 2022, Sampson and Groeller 2015) addresses them. We also wrongly described Sampson and Groeller (2015) as volume-equated; repetitions per set differed significantly between groups.
Shingo Yoshizaki
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