Lifting Tempo and Muscle Growth: How Slow Should You Go?
A new meta-analysis of 14 studies reveals that lifting speed has minimal impact on muscle growth, freeing lifters from tempo obsession.
Are those gruelling slow-motion reps at the gym actually worth the extra effort? This fresh meta-analysis picks through one of the most debated topics in strength training: whether slower repetition tempos truly deliver superior muscle growth compared to faster lifting speeds.
Key Points
Aim
The research team systematically analysed 14 studies to determine the independent effects of manipulating eccentric (lowering) and concentric (lifting) repetition tempos on muscle hypertrophy. Unlike previous reviews that examined total repetition duration, this study specifically isolated how the speed of individual muscle actions affects muscle growth.
Methods
Researchers conducted a comprehensive meta-analysis using Bayesian statistical methods to compare “slower” tempos (1.7-4.5 seconds, averaging ~3.5 seconds) versus “faster” tempos (0.3-2 seconds, averaging ~1 second) across 278 participants from 14 controlled studies. The analysis examined concentric and eccentric phases separately, with subgroup analyses based on body region, training to failure, and muscle action type.
Results
The findings revealed that faster and slower tempos produced similar muscle growth outcomes. When combining all studies, faster tempos showed a trivial advantage (pooled mean = 0.09) with a very low probability of meaningful differences. Specifically:
Within-group changes: Both faster (0.43 effect size) and slower tempos (0.34 effect size) produced medium-magnitude hypertrophic adaptations
Between-group differences: Central estimates trivially favoured faster over slower tempos
Subgroup analyses: No meaningful differences emerged between upper and lower body regions
Training to failure interaction: Faster eccentric tempos showed modest benefits when not training to failure, while slower tempos were marginally superior when training to failure
Related
Practical Takeaways
These results offer significant practical freedom for lifters and fitness enthusiasts. The research demonstrates that individuals can effectively use a wide range of repetition tempos (0.25-4.5 seconds) to promote muscle hypertrophy without compromising results. This is particularly valuable for:
Rehabilitation contexts: Those with joint issues can use slower, controlled movements without sacrificing muscle growth
Training variety: Coaches can manipulate tempo for program variation without worrying about suboptimal hypertrophy
Personal preference: Lifters can choose tempos based on comfort and safety rather than strict adherence to specific speeds
Load management: When unable to use heavy weights, slower tempos can provide adequate stimulus through increased time under tension
Key Takeaways
This comprehensive meta-analysis definitively shows that repetition tempo has minimal overall effect on muscle hypertrophy, challenging long-held beliefs about optimal lifting speeds. The research suggests that mechanical tension remains the primary driver of muscle growth regardless of tempo, and that coaches and practitioners should prioritise other training variables like volume and proximity to failure over specific repetition speeds. Most importantly, this study provides evidence-based reassurance that there is no single “perfect” tempo for muscle growth. It gives lifters the freedom to adjust their training based on individual needs, limitations, and preferences while still achieving optimal hypertrophic outcomes.
Reference
Enes, A., Piñero, A., Hermann, T., Zamanzadeh, A., Hennessy, T., Montenegro, D., ... & Schoenfeld, B. J. (2025). How slow should you go? A systematic review with meta-analysis of the effect of resistance training repetition tempo on muscle hypertrophy. Manuscript submitted for publication in Journal of Strength and Conditioning Research.
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