How fast should you perform your reps?

Short answer

For muscle growth, tempo barely matters. Reps lasting 0.5 to 8 seconds gave similar results in a meta-analysis; only very slow reps over 10 seconds tended to do worse.

Figures

0.5–8 s · per rep: similar growth
> 10 s · tends to be worse, uncertain data

From 0.5 to 8 seconds per rep, muscle grew similarly

What the analysis shows

Schoenfeld and colleagues analysed 8 studies lasting at least 6 weeks. Between 0.5 and 8 seconds per rep they found no clear difference. Very slow reps tended to be inferior, but the data did not allow a firm conclusion.

How to use it

Move the weight under control, without momentum, and do not let it drop. A fixed tempo mainly helps keep sessions comparable.

Sources

Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. · Schoenfeld · 2015 · Sports Medicine PubMed DOI Study note
Meta-analysis, 8 studies on repetition duration.

Summaries by SetCtl, not medical advice.