Does Slowing Down Your Reps Actually Build More Muscle?
By Adi · September 18, 2026
No—rep tempo barely moves the needle on hypertrophy. Faster or slower concentricts and eccentrics (within a normal range) both grow muscle about the same.
The Core Finding
No—rep tempo barely moves the needle on hypertrophy. Faster or slower concentricts and eccentrics (within a normal range) both grow muscle about the same.
A 2025 systematic review and meta-analysis led by Alysson Enes with Brad Schoenfeld and colleagues pooled 14 studies (278 participants) that deliberately changed either the concentric or eccentric phase while holding other variables constant. Both faster tempos (roughly 0.3–2 s per phase) and slower ones (1.7–4.5 s) produced solid, medium-sized growth. Head-to-head, any difference was trivial and favored the faster side only slightly—with high uncertainty. The same pattern held for upper vs lower body and for both lifting and lowering phases.
🏋️♂️ Key Takeaways
Stop obsessing over the stopwatch: Use any controlled tempo you prefer between ~0.25–4.5 seconds per phase. Muscle growth will be essentially identical.
Prioritize the big rocks: Volume, progressive overload, and proximity to failure matter far more than exact cadence.
Keep the eccentric controlled, not theatrical: Dropping the weight like a hot potato risks joints; a 1–3 second lower is plenty.
Match the tempo to the exercise and goal: Explosive concentricts can help strength/power work; a slightly slower eccentric can feel better on isolation moves. Neither is required for size.
⚠️ The Catch (Study Weaknesses)
Most included trials were relatively short (~8–9 weeks on average) and used modest sample sizes. Certainty of some subgroup estimates (especially failure vs non-failure interactions) was lower. Extremely slow tempos (>8–10 s total) were largely outside the analysis and still look suboptimal from older data because load has to drop too far.
📲 The Adi.fit Application
Busy parents and professionals: quit counting “3-second lowers” in your head during a rushed 45-minute session. Pick a natural, controlled tempo that lets you feel the muscle and stay safe, then focus on adding weight or reps over time.
Log every working set in the Adi.fit app—track the load, reps, and how close you got to failure. The app’s progressive overload tools and weekly volume summaries will show you the real drivers of growth while tempo stays a free variable you can adjust for joint comfort or preference.
Scientific Reference: How Slow Should You Go? A Systematic Review With Meta-Analysis of the Effect of Resistance Training Repetition Tempo on Muscle Hypertrophy. Enes A, Piñero A, Hermann T, et al. (including Schoenfeld BJ). 2025. PMID: N/A (DOI: 10.1519/JSC.0000000000005302).