Time Under Tension, Rep Speed/Tempo and Eccentric vs Concentric

Two topics I purposely left out of my guide to creating The Ultimate Weight Training Workout Routine are time under tension and rep tempo. Why? Mostly because I didn’t feel they were important enough to include. Plus, I just didn’t think people would actually care about them.

I still think I’m right about that first part, but boy was I wrong about the second. Seriously. I’ve probably had someone ask me about these two subjects every single day since then, and I keep responding with the same ‘copy and pasted’ answer along with a promise to eventually write an article about it.

Today it’s time to finally make good on that promise.

Let’s first begin with the basics to make sure we’re all on the same page…

The Anatomy Of A Rep

The following is going to be pretty noob-ish stuff that most people already know, but since I know I’ll be referring a bunch of noobs to this page in the future, I can’t leave it out.

So, let’s break down the 4 steps of a typical rep of a typical set of a typical exercise:

  1. The starting position. This is where the weight is when you begin a rep of an exercise. For example, with a barbell biceps curl, this is the point when your arms are down at your sides and the barbell is down in front of your upper thighs.
  2. The ending position. This is where the weight is when you finish a rep of an exercise. For example, with a barbell biceps curl, this is the point when your elbows and biceps are flexed and the barbell is up in front of your chest.
  3. The concentric portion of the movement. This is the “lifting” or “positive” portion of a rep, when you are moving the weight from the starting position to the end position (against the resistance). With a barbell biceps curl, this is when you actually do the “curl” and flex your elbows/biceps to move the weight up towards your chest.
  4. The eccentric portion of the movement. This is the “lowering” or “negative” portion of a rep, when the weight is moving from the end position back to the starting position (with the resistance). With a barbell biceps curl, this is when you are extending your elbows and the barbell is being lowered back down towards your thighs.

And that brings us to two related topics involving exactly how these 4 steps should go…

Rep Tempo/Speed and Time Under Tension

  • Rep tempo (sometimes called “rep speed”) refers to the tempo (or speed) at which you perform a rep of an exercise. For example, 2 second concentric, 1 second pause at the top, 3 second eccentric, 1 second pause at the bottom (this is just one completely random example, by the way).
  • Time under tension (aka TUT) refers to how long each set lasts, or really the total amount of “time” your target muscles are “under tension” during a set of an exercise. For example, you might see something along the lines of 1-20 seconds being ideal for strength, 20-60 seconds being ideal for muscle growth, and 60+ seconds being ideal for muscular endurance.

Time under tension can generally be increased or decreased two ways. The first is by simply doing more or less reps in a set. So, a set of 10 reps will (typically) lead to more time under tension than a set of 5 reps on a given exercise.

The second way is by adjusting the rep speed. If you perform that set of 5 reps with a slower tempo and/or the set of 10 reps with a faster tempo, the set with fewer reps can become capable of providing a larger time under tension than the set with more reps.

How Important Is Time Under Tension?

I think the idea of TUT is an important aspect of your training, especially when the goal is muscle growth. Because, after all, you do want your muscles to be under a certain amount of tension.

But at the same time, I don’t actually think you need to give a crap about it.

Not even half a crap, in fact.

What I mean is, if you’re exclusively doing a bunch of REALLY short sets, I don’t think you’ll be training optimally for muscle growth. Similarly, if you’re exclusively doing a bunch of REALLY long sets, I also don’t think you’ll be training optimally for muscle growth.

But, you know this already. It’s why exclusively doing really low reps (like 1-5) or really high reps (like 15+) wouldn’t be ideal for muscle growth either. And it wouldn’t. The first would be more ideal for strength, and the second would be more ideal for endurance.

This of course is why I recommend 5-15 as the ideal rep range for muscle growth, along with a rep tempo that is neither too slow nor too fast (more on that in a second).

Which is all just my way of saying that you don’t need to focus at all on how long your sets are taking. No need to set a watch. No need to count in your head. No need to purposely make your sets last a specific number of seconds.

What you should focus on is making sure your overall workout program is designed intelligently for your goal (optimal volume, frequency, intensity/rep ranges, exercise selection, etc.), that you’re using good form/properly training the target muscle group(s), and that you’re creating progressive overload.

That’s the stuff that matters.

And as long as you’re doing that stuff right, guess what? Your time under tension will automatically end up being whatever the hell it should be and the rest will take care of itself.

How Important Is Rep Tempo/Speed?

I’d say it’s important, but not enough to turn it into a mess of over-complicated specifics.

Let me explain.

I definitely think there is a right way and a wrong way to perform each rep of each exercise. There is a “good” general speed and tempo, and then there’s the opposite of that which I think can best be described as either stupidly fast and stupidly slow.

And as long as you’re avoiding those stupidly fast/stupidly slow extremes and fall somewhere in the middle, you’re probably doing your reps just fine.

Simple as that.

So while rep tempo can certainly have its uses, I honestly don’t put much emphasis on it and almost never use or prescribe a specific number of seconds for the concentric or eccentric portion of a rep. I find it’s more of a distraction than anything else. I’d much rather see 100% of the focus during a set be on proper form, using the target muscle(s), and progression… not counting seconds.

That doesn’t mean I don’t have a slightly more specific recommendation for you, though.

Here’s What I Recommend

For most of the people, most of the time, I like to see the weight lowered under control on the way down, and then exploded back up.

Allow me to break that down…

The Eccentric

Regardless of the exercise being done, you should lower the weight in a slow, smooth and controlled fashion. Definitely NOT super slow (that’s a whole other idiotic training method for another day). Just slow enough so that you and the target muscles are fully in control of the weight rather than just gravity alone.

This would mean that the weight is NOT just dropping and you’re NOT just letting it fall and lower on its own. You’re controlling it the whole way down.

The Concentric

As for the lifting portion, this can vary depending on the exercise being done.

In most cases however (especially most compound exercises), you should explode the weight. Or, as I sometimes like to describe it… hit your reps with a purpose.

Meaning, don’t intentionally slow down the speed of this part of the rep. Try to move it from the starting position to the end position in a quick and explosive manner. This DOES NOT mean throw the weight, or bounce the weight, or swing the weight, or use momentum to get the weight where it needs to go.

It just means, in a controlled fashion where proper form always remains intact and nothing funny/stupid makes an appearance, you should move the weight from point A to point B in a powerful, forceful, swift motion. Hit that rep with a purpose.

Are There Exceptions?

Yes, some exceptions to these recommendations do exist.

For example, calves tend to benefit from a slower eccentric and a pause at the bottom. And certain exercises are just less suited for being “exploded” (e.g. isolation exercises where the focus should be more on contracting/feeling/fatiguing the muscle rather than maximal strength output and progression). Plus, certain goals warrant doing certain things (such as speed benching).

But for the most part… controlled eccentric, explosive concentric is what I recommend.

No need to make it any more complicated than that.

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39 thoughts on “Time Under Tension, Rep Speed/Tempo and Eccentric vs Concentric”


  1. Being a ‘noob’ to your blog, I’m not really sure where best to ask my questions. Unless you don’t mind e mails about this stuff.

    But here’s a question I have had on my mind for a while. There seems to me that barbells are favored over dumb bells? (I realize there’s a bad joke hidden here someplace). In terms of exercises. I guess what I really asking is in the exercise routines you have outlined in the ” beginners” menu. Or can dumbells be used in lieu of barbells and i should know this? For example in the chest and shoulder press, dead lifts and squats.

      • Thanks, article was exactly on point. As I read it I found myself saying I (should have) knew that. HA.
        As always, which works for me. I don’t have a spotter and doing squats with a barbell bothers my shoulders. So I use a machine or leg press. I’m gradually working on squats with a barbell though. Just for the variety.

        Once again, thanks for the great advice.

  2. Does this apply to resistance bands as well? I use them for verity , and they are a-bit easier on the joints when winter time arthritis flares up.


    • In most cases I’d say yes, the same thing applies.

      Although, since bands are being used specifically because of injury issues and/or working around pain, things may need to be adjusted a bit to suit those needs.

  3. hi Jay..i just wanna thank you for the great online resource you have provided… I wish i had found out about this program earlier as it was just a the year back when i started weight training… so its only appropriate that i tell you about the things ive learnt after going through your book now at the start of the next year.

    Being a novice with no prior experience and knowledge i tried a couple of much hyped programs like tony hortons p 90 x and vince del monte’s hypertrophy max to name a few… what i felt was that these were really too exhaustive for a begginer with very high volume and i would hit the gym and sleep for pretty much the rest of the day …. What’s more these were like 5 or 6 day programs…. what eventually happened was me losing a couple of pounds without gaining much muscle….and of course skipping the gym and not being able to stick to any particular routine …
    until a workout routine happened…and ive had some amazing results…with my workout time cut to more than half…gonna stick to this now :):)
    thanks and have an amazing year ahead

  4. Happy New Year Jay! Did you see that study that showed that light weight with lots of reps or heavy weights with less reps that both brought muscle to failure, produced the exact same muscle growth? In this study, they found that the only difference, was the lower rep heavy weight group gained more strength, but not more muscle. Their conclusion was muscle fatigue regardless how you do it, produced the same hypertrophy, BUT when it came to measuring strength, those used to lifting heavier performed better. You can find this with a simple Google search. What is your opinion of this study?

    Also, what do you think of Kettlebell workouts? I happen to really like doing them. They don’t seem to fall nicely into cardio, resistance or any category exactly. I do one arm raises, 2 arm raises, cleans, snatches, sumo squats, various other exercises with a 35 lb.d Kettelbell. I feel that it make some more “athletic” and gets my heart pumping like a HIIT.

    • I think I know know study you’re talking about, and I think higher rep training can certainly produce muscle growth. It’s part of why I like the 5-8 rep range for the big important stuff, and anywhere from 8-15 for the secondary stuff. Even higher reps than that can produce growth too of course, but I tend to stay away from going that high in reps because it will not be optimal for strength progression and cardiovascular fatigue will likely cause form to go to shit on most exercises as you get higher and higher in reps.

      As for kettlebells, they are a tool like any other that can be beneficial for certain goals at certain times. I personally don’t use them much, though.

  5. Again, thank you for bringing a sense of sanity to a sport where superstitious ritual is often mistaken for science and super egos often cloud good judgement and common sense.

  6. Great article Jay!

    I hope this helps you to get less questions on things that don’t really matter.
    I never payed attention to this since, by reading your guide and understanding the principles, these concepts were automatically taken care of.

    Good job!

  7. All your articles are very useful and always hilarious and informative. I am 45 year old (5’3″, 135 lbs, 17% BF) and have been workout for about 2 years now. I wish I have found your website sooner, but better late than never. I have try workout plan from PhD dude, P90x dude and countless other from low rep, to high rep (I kid you not, 50 reps for shoulder press…I was like ‘Shit’, I can’t do that with no freaking weight), HIIT training classes ($80/month), to mention a few. I almost feel embarrass mentioning it because I consider myself a fairly well educated guy. I have been in better shape now than before obviously, but can’t seem to lower my BF no matter what programs I try (or how much money I spent..lol). Long story short, I just got your guide and will do the 4-day split (It fits my schedule and preference). The hard part is watching my diets to maintain the calorie deficit (…damn I love wings and beers during football season). I really don’t have any question (I was having a few but you tend to have already answered here somewhere), I just want to say ‘thank you’ for simplified the process. Will let you know how it goes in about 3-6 months…Have to let the routines work for you, right? Thanks, Jay

    • Very happy to hear it! Looking forward to your progress updates.

      And you’re right, the hard part for most people is never the training part… it’s the diet part. And when it comes to fat loss, the diet part is honestly the only part that truly matters. Nailing that down is the key.

  8. Great website jay your advice virtually mirrors every ing my pt had taught me which shows I have a good one .

    Regarding reps etc and this study for muscle growth I personally think for pure looks it really doesn’t matter what rep range you do . It all about pushing your muscle group to failure or close to -How you do that from a looks pov is irrelevant . However as a secondary benefit. Lower reps will provide strength and higher reps will increase muscular endurance, possibly burn more calories if it’s in the moderate 10 to 12 range. I tend to use a combination during my training week so first chest session will do lower reps and second will do higher. Or I might start with heavier reps then drop to lighter reps when tired in same session. What do you think?

  9. Would you do me a personal favor and write an article about crossfit? Not because I am wondering what your opinion is, I think I might have a pretty good idea where you probably stand (although I could be wrong). I just want to READ an article written by you about crossfit….because I bet it would be hilarious and awesome. Please?

  10. Just reading your blog on various topics. I must say finally i found a good place to get sound advice. Thank you

  11. Hey I was wondering about my breathing during reps. I have heard you should breath in and out with the eccentric and concentric parts of the movement but when I do this I feel like I am not getting enough air so I just breath normaly and make sure I am breathing. Do you think I should keep this up or change it? Thanks

  12. Thanks, this is another good no-nonsense article. I would like to add that during my 20 years of lifting, I have found that significantly reducing the weight used while increasing reps and slowing the tempo has allowed me to continue to progress during injuries and times when my joints were too sore from lifting heavy.

  13. Hi Jay!
    I basically train using my bodyweight (pullups, dips, etc)
    So when i reach the top end of the rep range (let’s say 8 reps for pullups) basically i am left with time under tension for more progressive overload or going higher than the rep range.
    Aside from the obvious (adding weight to the exercises), which is the best way to go? The 8 reps for pullups, for example: shoot for 9, 10, 11… or do those 8 more slowly, feeling the muscle, perfecting form, etc?

  14. I have a question in this subject.

    In some cases we are training in a environment where there is no heavy weights available for training.

    For example, I have only 20Kg in weights and this shit is very expensive. I use the same 4x5kg in my dumbell bars and in my barbell bars. I also, during my Kung Fu trainings, do a set of push-ups and planks.

    In this scenario, can I efficiently use slow reps (or even isometrics) to make a progression? Or is this totally bullshit?

    Great blog, I’m learning a lot here! I’m now sure about some things that I already knew and I’m also learning new things and fixing misconceptions.

    • Slow reps is crap, assuming it’s the type of slow reps I’m thinking of. A better idea would be to progress by increasing reps and/or decreasing rest periods, and finding other ways to increase the resistance.

      • Thank you by answering!

        When I say slow reps I mean doing the entire rep more slow, not holding in some points of the movement.

        Now I’m in cutting. I think I will buy more weight to use in my dumbbells/barbell to when I start bulking.

        Also, I need some advice in the matter of bulking.

        I train Kung Fu in Wednesdays and in Fridays. The train consists in 2:30 hours of exercise, mixing cardio, strength, explosion, etc, using the entire body (most of legs and shoulders). I also do during the training 4 sets of straight push-ups and some short sets of planks (straight, lateral, star).

        I was thinking about to do a weight workout in Sunday and other in Monday, mainly with compound exercises (and only free weights – I don’t have machines at home).

        What do you recommend?

        I thought in legs/back in Sunday (squat, deadlift, lunge and bent rows) and chest/shoulders in Monday (inclined dumbbell bench press, inclined flying, clean and press, crush grip dumbbell press and lateral raises). But I’m concerned about using my shoulders two days in a row.

        What do you think?

        Thanks in advance, and once again: amazing site, I’m learning A LOT here.

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