TUT vs. Effective Reps Theory

What’s Best for Hypertrophy?

What builds more muscle? Time under tension or training to failure or close to it? Here’s what you need to know.

What’s the optimal time under tension (TUT) for a set or rep? There’s no such thing! To understand why, you have to understand the effective reps theory.

The Bullet Points

  • Time under tension refers to the duration of a set in seconds. If you do 10 reps with a 3-second eccentric (lowering phase) and a 1-second concentric (lifting phase), the TUT will be roughly 40 seconds.

  • From an energy systems perspective, there’s some logic to paying attention to TUT. For hypertrophy, not so much.

  • Tension builds muscle, but it’s all about getting enough “effective reps” in a set. The effective reps in your set are the ones that recruit the growth-prone fast-twitch fibers.

  • Effective reps require a high level of effort. You also need a high amount of tension in those fibers. The slower your reps, the more tension. That doesn’t mean going slow on purpose. It means you’re trying to lift the weight at a normal speed and push hard, but the movement gets slower because fatigue sets in.

  • Normally, the last 4-6 reps of your set are the effective reps, regardless of the total number of reps you’re doing. So, TUT doesn’t factor into that.

  • Adding more non-effective reps just to increase TUT doesn’t build muscle.

  • Increasing the duration of a rep’s eccentric phase (negative) can be beneficial, but only to a point.

  • I don’t even consider TUT when programming.

You could think about it like this:

  • If you train to failure, those last 5 (4-6) reps are effective at stimulating hypertrophy.
  • If you stop one rep short of failure, you have about 4 effective reps.
  • If you stop two reps short of failure, you have about 3 effective reps.
  • Etc.

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So would rest pause training/ drop sets increase the number of effective reps in a set?

Yes. That is the purpose of rest/pause and drop sets.

I personally prefer rest/pause because the drop set tends to ass non-effective reps too.

So when doing a drop set, I prefer to only do a small drop so that I can add, at the most 6 additional reps… any reps above that will be non-effective reps that just cause more fatigue.


Thanks for the reply Christian. I’ll be sure to put this info to good use the next time I’m pumping the iron!