Should I Lift Fast or Slow?

When you go to the gym, you’ll often see a certain group of people cranking out reps as fast as they can, while others appear to be moving in Matrix slow motion as they go through their workout.

So what’s the deal?

Like pretty much anything else that goes on in a typical gym, most days you’ll see people doing completely different things, and it can be a little hard sometimes to figure out who actually knows what they’re doing and who is just being weird.

Fast or slow?

When we talk about lifting weights “fast” or “slow,” what we’re really talking about is a concept called tempo, which is one of the variables that we can manipulate when it comes to our workout. 

These variables include exercise type, exercise intensity, the order of exercises, load (amount of weight lifted), number of sets and reps (volume), frequency of exercise, length of rest periods or recovery, and tempo/speed.

How we should adjust these different variables really depends on the goals we’re trying to achieve in the gym.

So does tempo even matter when lifting?

Short answer: not as much as you would think.

The idea behind adjusting the tempo or speed of your lifting movement goes back to a concept known as “time under tension”, which simply means how much time you are actually lifting (or lowering) the weight.

When you consider the time you spend in the gym choosing an exercise, waiting, preparing, and then recovering from that exercise—the amount of time you spend doing the exercise is fairly short. 

Generally speaking, we’re talking about 10-30 seconds. That doesn’t seem like much time, so it got the researchers thinking…

 We know that the amount of time our muscles are working is an important factor for muscle growth, so what if we intentionally slowed down our reps to increase our muscles’ time under tension?

The good intentions of super-slow weight training

This is one of those times when something that seems to make a lot of sense in theory doesn’t appear to work in the real world.

In fact, research has shown here and here that extremely slow tempos (~10-seconds) create less muscle growth than simply lifting heavier weights at a normal speed.

Part of the problem is that when we deliberately slow down our reps, we end up doing less of them. So even though time under tension is important, it’s probably not as important as some of the other variables, such as total exercise volume, intensity, and frequency.

In other words, doing more reps is more important than increasing your time under tension.

So then does lifting fast build more muscle?

So if super-slow training doesn’t work, what if we speed up our tempo instead to squeeze in a few extra reps before our muscles give out.

These “fast” lifters are also the people you see racing from one machine to the next because they have heard that shorter rest periods lead to bigger muscles.  

It all comes back to your goals for training. 

If you are looking to build power, there is certainly a place for fast, explosive lifting, but if you are looking to build strength and muscle, training as quickly as possible is probably not the way to go.

The problem here comes down to physics, where the force/velocity curve essentially says the heavier the weight is that you are lifting, the slower you will be able to lift it. 

In other words, we can either lift fast or heavy, but not both at the same time. And when it comes to building strength and muscle, it’s more important that we lift heavy than fast.

It turns out that the best option for most of us is not lifting fast or slow, but somewhere in between. 

Controlling the eccentric movement

Although speed may not matter as much as we once thought, there is still a difference between controlling a weight during the eccentric phase and simply letting the weight drop with gravity.

Your goal should be to control the weight on the way down while still moving fast enough to take advantage of the muscle’s natural stretch reflex, which will dissipate if you move too slowly. 

Instead of thinking about the speed of the rep, focus on keeping your muscles tight and controlling the eccentric movement until you can explode powerfully into the concentric movement.

Like so many other things when it comes to health and fitness, I think we have this tendency to focus on things that have very little impact on our overall results instead of the stuff that will make the biggest difference. Things like how much you lift (load/intensity), how many times you lift it (volume), and how often you do it (frequency).

So what is the best lifting tempo?

It turns out that the best tempo is probably the one where you are not thinking about how fast or slow you are lifting.

There was actually a meta-analysis done on this that found that the optimal lifting speed is probably somewhere between 2 seconds (1 second up and 1 second down) and 6 seconds (3 seconds up and 3 seconds down) 

In other words, fast enough that you can get as many reps as possible done in a set, but slow enough that you are still controlling the weight and not injuring yourself in the process.

Personally, I think that a 6 second rep is kind of pushing it, and I don’t see how you can maintain your overall volume and intensity with a 3 seconds up and 3 seconds down tempo. I would recommend sticking with something between 2-4 seconds—or better yet, stop thinking about it at all and focus more on lifting heavy things as many times as possible.

Mixing things up 

Now having said that, if you have hit a plateau in your training, sometimes changing up the tempo (temporarily) is a good way to mix things up and encourage your muscles to adapt to something new.

Just as you can alternate between heavy/light days and low-rep/high-rep days, you can also use faster and slower tempo days to add a bit of variety to your workouts and keep your muscles engaged. Just remember there is a fine line between “mixing things up” and losing sight of the things that will ultimately make the biggest impact (i.e. load, intensity, volume, frequency).

There is one part of my workout, however, where I do like to mix in some slow deliberate reps, and that’s during my warm-up sets. 

Because I am already using a lighter weight for my warm-up, instead of just cranking out a few full speed reps, I like to slow things down to focus on my technique. I will also pause for a moment at the bottom of the rep (eccentric stretch point), which helps to prepare the muscles, tendons, and ligaments that I’ll use for that particular exercise.

I find this type of slow deliberate warm-up especially useful for any exercise that involves the shoulder, hip, or knee joint. 

The bottom line:

Research has generally shown that tempo doesn’t make much of a difference when it comes to muscle growth. 

Although time under tension is an important variable in your workout, it’s probably best to avoid super-slow tempos (>10 seconds) if you are trying to maximize strength and muscle growth.

Overall, the best tempo is probably the one where you are not thinking about how fast or slow you are lifting.

At the same time, make sure that you are controlling the eccentric portion of the lift. Don’t simply drop the weight or lose tension, but use a quick controlled eccentric movement to take advantage of the muscle’s stretch reflex.

If you have hit a plateau in your training, it’s okay to experiment with different lifting tempos and mix things up in order to add variety and stimulate new muscle growth.

What do you think?

Have you ever deliberately changed up the tempo of your workout? What did you do, and what kind of benefits or problems did you discover when you switched things up? If you would take a moment to share your story with us in the comment section below.


Chaves et al. Effects of resistance training with controlled versus self-selected repetition duration on muscle mass and strength in untrained men. PeerJ. March 6, 2020  

Goto K, et al., Hormonal and metabolic responses to slow movement resistance exercise with different durations of concentric and eccentric actions. Eur J Appl Physiol. 2009 Jul;106(5):731-9.

Nóbrega,Sanmy Rocha, et al., Self-selected vs. Fixed Repetition Duration: Effects on Number of Repetitions and Muscle Activation in Resistance-Trained Men J Strength Cond Res. 2018 Sep;32(9):2419-2424.

Schoenfeld, BJ, et al., Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. Sports Med. 2015 Apr;45(4):577-85.

Schuenke, Mark D, et al., Early-phase Muscular Adaptations in Response to Slow-Speed Versus Traditional Resistance-Training Regimens. Eur J Appl Physiol 2012 Oct;112 Epub 2012 Feb 12 

Wilk Michal, et al., Does Tempo of Resistance Exercise Impact Training Volume? J Hum Kinet. 2018 Jun; 62: 241–250.

Wilk Michal, et al., Changes of Power Output and Velocity During Successive Sets of the Bench Press With Different Duration of Eccentric Movement. Int J Sports Physiol Perform. 2020 Jan 14:1-6.

Wilk, Michal, et al.,  The Effects of the Movement Tempo on the One-Repetition Maximum Bench Press J Hum Kinet. 2020 Mar; 72: 151–159. 

Drew Kimble CSCS*D, CPT
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