Repetition tempo: slow or fast for building muscle and strength?
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Lifting the bar with maximal intended speed almost doubled bench press gains in a 6-week trial, and for muscle, reps lasting from half a second to 8 seconds all work. Which tempo to use for your goal, how it is written and the mistakes worth avoiding.
In 2014, Juan José González-Badillo and his team at Pablo de Olavide University in Seville had 20 people train the bench press 3 times a week for 6 weeks. Both groups moved the same weights, with the same sets and reps. Only one thing changed, controlled with a sensor on the bar: one group lifted each rep as fast as they could and the other at half that speed. The fast group improved their max by 18.2%; the slow group by 9.7%.
Six weeks, the same weight, almost double the improvement. And yet social media is full of routines with 4-0-4 tempos or endless lowering phases “to feel the muscle”. What does the evidence say about repetition speed? It depends on whether you are after muscle or strength.
Tempo and muscle: a very wide range works
The meta-analysis by Brad Schoenfeld, Ogborn and Krieger (2015) pooled the 8 studies comparing different repetition durations with sets taken to failure for at least 6 weeks. Their conclusion: hypertrophy was similar with reps lasting between 0.5 and 8 seconds. Only deliberately very slow reps, over 10 seconds, seemed worse for muscle, although there were too few studies to say so with certainty.
The review by Michał Wilk and colleagues (2021) reaches a similar point: tempo influences variables such as time under tension or how many reps you can complete, but the evidence on its long-term effect is not conclusive, and hypertrophy guidelines usually apply to a naturally chosen tempo.
| Study | What it compared | Result |
|---|---|---|
| Schoenfeld (2015), 8 studies | Repetition duration, sets to failure | Similar muscle from 0.5 to 8 seconds; worse above 10 |
| González-Badillo (2014) | Lifting at maximal versus half speed, bench press | Max: +18.2% versus +9.7% |
| Davies (2017), 15 studies | Fast versus moderate or slow reps | Similar strength; trend favouring fast reps at 60-79% of max |
| Pareja-Blanco (2017) | Stopping the set after losing 20% or 40% of speed, squat | Same strength with 40% fewer reps; more muscle when letting speed drop further |
Tempo and strength: lift with intent
For strength, the story changes. González-Badillo's trial showed that trying to move the bar as fast as possible on the way up almost doubled the improvement. Note: with heavy loads the bar moves slowly anyway; what counts is the intent to accelerate it.
The meta-analysis by Davies and colleagues (2017), with 15 studies, was more cautious: fast and moderate or slow reps improved strength similarly overall. But with moderate loads, 60 to 79% of max, there was a trend favouring fast reps (effect of 0.31), and the result did not change with age or experience.
The practical rule: lower under control, without dropping, and lift with maximal intended speed even if the bar does not move fast. It works for muscle and adds to strength.
How a tempo is written (and when you need one)
Tempo is usually written with four numbers: lowering, pause at the bottom, lifting and pause at the top, in seconds. A “3-1-1-0” means lowering in 3 seconds, pausing for 1 at the bottom, lifting in 1 and not pausing at the top. Sometimes an X is used to mean “as fast as possible”.
| Goal | Lowering | Lifting | Why |
|---|---|---|---|
| Building muscle | 2-3 seconds, controlled | 1-2 seconds | Within the 0.5 to 8 second range that works |
| Building strength | Controlled | Maximal intended speed | Almost double the improvement in the 2014 trial |
| Learning technique | Slow, 3-4 seconds | Controlled | Gives you time to feel and correct your position |
| Not worth it | Reps longer than 10 seconds | Worse result for muscle in studies | |
Speed also tells you when to stop
The same Seville researchers use speed for something else: deciding when to end the set. In the trial by Pareja-Blanco and colleagues (2017), 22 men trained the squat for 8 weeks, stopping each set after losing 20% or 40% of the speed of the first rep. Both groups gained the same strength, although the 20% group did 40% fewer reps and improved their jump more (9.5% versus 3.5%). The 40% group, closer to failure, gained a bit more muscle in two of the quadriceps.
Without a sensor, the practical way to apply this is to count the reps you have in reserve: when reps start to slow down a lot, you are close to failure. We explain it in RIR and RPE, and in training to failure you will see when it pays to push harder.
Common tempo mistakes
- Dropping on the way down: losing control of the bar is not “going fast”, it is losing technique. Controlling the descent also protects your joints.
- Endless lowering phases “to feel the muscle”: they lengthen the session, force you to use less weight and, above 10 seconds, studies give them no advantage.
- Counting the tempo and forgetting the range: a good tempo with half the range is still half the range; we cover it in full or partial range of motion.
- Deliberately lifting slowly with heavy loads: if you are after strength, intended speed is what adds up.
The Progrevia generator sets the tempo for each exercise according to your goal: 3-0-1-1 for hypertrophy, with a controlled lowering phase within the range that works, and 2-1-X-0 for strength, with a pause at the bottom and maximal-speed lifting. If you are starting out, the beginner strength routine gives you a base with progression, and in the mechanisms of hypertrophy you will see why tension matters more than the clock.
- Schoenfeld BJ, Ogborn DI, Krieger JW. Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. Sports Medicine. 2015;45(4):577-585.
- González-Badillo JJ, Rodríguez-Rosell D, Sánchez-Medina L, Gorostiaga EM, Pareja-Blanco F. Maximal intended velocity training induces greater gains in bench press performance than deliberately slower half-velocity training. European Journal of Sport Science. 2014;14(8):772-781.
- Davies TB, Kuang K, Orr R, Halaki M, Hackett D. Effect of movement velocity during resistance training on dynamic muscular strength: a systematic review and meta-analysis. Sports Medicine. 2017;47(8):1603-1617.
- Pareja-Blanco F, Rodríguez-Rosell D, Sánchez-Medina L, et al. Effects of velocity loss during resistance training on athletic performance, strength gains and muscle adaptations. Scandinavian Journal of Medicine & Science in Sports. 2017;27(7):724-735.
- Wilk M, Zajac A, Tufano JJ. The influence of movement tempo during resistance training on muscular strength and hypertrophy responses: a review. Sports Medicine. 2021;51(8):1629-1650.
Progrevia · · How we write our guides
Frequently asked questions
Do slow reps build more muscle?
No. In the meta-analysis by Schoenfeld (2015), hypertrophy was similar with reps lasting between 0.5 and 8 seconds, and reps longer than 10 seconds seemed worse.
Should you lift the bar fast to build strength?
It pays to lift it with maximal intended speed. In the trial by González-Badillo (2014), that improved bench press max by 18.2%, compared with 9.7% when lifting at half speed.
What does a 3-1-1-0 tempo mean?
Lowering in 3 seconds, pausing for 1 second at the bottom, lifting in 1 second and not pausing at the top. The numbers always go in that order: lowering, bottom pause, lifting and top pause.
How long should the lowering phase take?
For building muscle, a controlled 2-3 second descent works well and is within the studied range. The key is not to drop the weight.
Can speed tell you when to stop a set?
Yes. In the trial by Pareja-Blanco (2017), stopping the set after losing 20% of speed gave the same strength as stopping after 40%, with 40% fewer reps.
Informational content based on the available scientific evidence: it does not replace advice from a healthcare professional. If you have an injury or a medical condition, or are pregnant, check with one before changing your training or diet.
