Does lifting tempo matter?
Not much: anything from half a second to eight seconds per rep built muscle about equally, as long as the set was hard.
“Time under tension” is a worse predictor than it sounds. Slower reps mean fewer reps at the same weight, so the total work ends up similar, and so does the growth.
Two things still matter. Control the lowering instead of dropping the weight, because that is where the muscle works under stretch, and use the full range. Beyond that, lift at the speed that lets you keep form and add weight over time.
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Sources
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- Schoenfeld, B.J. et al. (2015). Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. Sports Med 45(4). 8 studies, all training to failure: growth was similar across rep durations of 0.5 to 8 seconds.
- Refalo, M.C. et al. (2023). Influence of resistance training proximity-to-failure on skeletal muscle hypertrophy: a systematic review with meta-analysis. Sports Med 53(3). What the set has to deliver is effort close to failure.
- Wolf, M. et al. (2023). Partial vs full range of motion resistance training: a systematic review and meta-analysis. Int J Strength Cond 3(1). Range of motion is the part of technique that does show a difference, generally favouring the full range.