Time Under Tension: Everything You Need to Know

Time Under Tension: Everything You Need to Know

TUT or Time Under Tension is a technique that helps optimise muscle hypertrophy. Here’s how to use it!

What does time under tension mean?

TUT stands for Time Under Tension; that is, a principle based on the portion of time that muscle fibres are under constant tension during weight training exercise, causing fibrillar “micro-tears” which are the key to muscle growth.

The time under tension technique maximises muscle volume gain and the creation of new tissues.

When using the technique, a simple rule is to avoid blocking the joint. That’s to say, the weight shouldn’t be at the end of the exercise or at the beginning, and it’s important to maintain a slight bend of the elbow, knee, shoulder…

TUT is fully oriented towards muscle hypertrophy.

What are mechanical stress and metabolic stress?

These are two related but somewhat opposite terms, and a balance between the two concepts will help generate maximum hypertrophy:

On the one hand, mechanical stress is related to the intensity of the load, that is, getting as close as possible to our 1RM or Repetition Maximum.

Training with a high load is synonymous with high mechanical tension and, with it, contributes to greater development of strength and muscle hypertrophy.


Time Under Tension and Hypertrophy

For its part, metabolic stress is related to the density of training, that is, the volume of training: sets and repetitions.

High metabolic stress will generate a large accumulation of metabolites: lactate, inorganic phosphate, hydrogenations… which also have an important role in terms of muscle hypertrophy.

Time Under Tension for Hypertrophy

Remember that hypertrophy is the consequence of creating new muscle tissues based on stimulus (training) and correct diet (nutrition).

Depending on the stimulus generated, the body counteracts by synthesising new tissues in accordance with the intensity of the stimulus so that it’s prepared to withstand it for future work.

We force the body to make us stronger, and we develop new muscle mass.

In doing so, the mechanical tension applied during load training is crucial: tension is created at the moment our muscle has to support as opposed to the lifting we do.

The higher the tension applied, the greater the signalling through the mTOR pathway, and therefore, the greater the synthesis of muscle protein…

What is a TUT exercise?

A TUT exercise implies using the technique to promote muscle hypertrophy by applying a certain execution tempo to each repetition.

This is essentially how it works. However, mTOR signalling is inhibited after about 60 seconds of tension, and if the load isn’t quite right, tension is reduced.

The key is finding the right load-tension relationship.

TUT in exercises

When lifting a really heavy load, but only one, we generate a lot of tension, but the tension time will be reduced.

Therefore, our “mission” is to find the right load to help us generate the corresponding stimulus, and maintain a total tension of less than 60 seconds.

What is tempo in exercise?

When we talk about “tempo” we’re talking about the fraction of time the movement of the load is divided into when we apply the TUT. Let’s look at the 4 phases we’ll divide the execution of the exercise into:

  • Eccentric Phase: This is the phase in which the load moves in relation to gravity, so the muscle is “relaxed”.
  • Final Phase: This is the point where the load moves from the end of the eccentric phase until the concentric phase begins.
  • Concentric Phase: The part of the movement in which force is exerted against gravity and muscle contraction occurs properly.
  • Beginning Phase: Phase in which the ROM is almost complete, but without reaching it, and for this we’ll always leave a slight joint bend.
Example of Squat with Tempo “202x”:
  1. Eccentric Phase (2): it takes 2 seconds from the start of the repetition to go through the eccentric phase (get down on the squat).
  2. Final Phase (0): once we’ve reached the lowest point of the squat, we don’t wait to go up and start the concentric phase.
  3. Concentric Phase (2): the primary phase of movement, where we truly “squeeze” and muscle contraction occurs. In the example, it lasts 2 seconds.
  4. Beginning Phase (x): right from the end of the concentric, and then we start again with the next repetition. We won’t rest for the example.

How long should a set last for hypertrophy?

If a repetition takes us 5 seconds to perform, then a set of 6-12 repetitions to emphasise load and tension would take us 60 seconds.

How long should my weight routine last?

Another determining factor when planning our “hypertrophy strategy” is to be clear that workouts lasting over 1 hour tend to also inhibit the mTOR pathway, due to the metabolic load or excess work.

Testosterone levels are significantly reduced in long workouts, which isn’t ideal for muscle growth. Hormones such as cortisol are at work here.

In turn, such ATP-intensive workouts cause mTOR signalling to decrease, meaning we use as little of this substrate as possible and maximise the time under tension, if hypertrophy is our goal.

In short, if we want to generate greater hypertrophy, based on what has been explained, we’ll have to completely recover between sets and avoid the high metabolic demand induced by the activity.

Tips for Increasing Time Under Tension

Below are some recommendations for using the technique:

Use Machines

I always prefer free weights, but there’s no question that machines can play their role if the specific purpose, and the method of application, are well set out. If we’re going to carry out training sessions where the concentric part is of interest, the machines will be of great help.

Increasing TUT

The muscles simply need to be stimulated by the tension applied, so you can use the machines for specific sessions emphasising TUT.

Another advantages of the machines for our purpose is that if we “fail” to perform the TUT, we won’t need anyone next to us to avoid any “catastrophe”… although we might need one to give us encouragement :).

Perform Descending Sets

With machines, we can perform descending sets, taking advantage of the fact that it’s easy to vary the load and thus always allow the maximum tension to be maintained for 60 seconds.

2 descending sets will be enough to maximise the TUT technique:
  1. Start with a weight you’re able to move 2-4 times, maintaining tension, then quickly change the weight and lower it.
  2. Doing so, we’ll essentially be stimulating the maximum number of motor units, with some muscle fibres fatiguing at first, and then generating the work in other units of a more resistive nature.

Performing Unilateral Movements

Another important element to consider is how to divide the symmetrical work of our limbs. For this, we’ll use exercises such as curls, working with both limbs but only one at a time in the concentric phase, doing all the work.

Try to use the “supporting arm” to start the movement, and when you can no longer hold the eccentric, finish the set or don’t exceed the 60 seconds period.


To maximise muscle gain if your goal is to achieve maximum hypertrophy:

  • Move within a range of 6-12 reps.
  • Creates sufficient tension to apply the necessary stimulus.
  • Keep the duration of the tension time under 60 seconds.
  • Avoid highly strenuous activities and generate metabolic demand.

Related Entries

  • Do you know about Hybrid Workouts for better gains? Click here
  • If you like Cross-Training, are you be interested in orienting your training towards hypertrophy? We tell you how to do so here.
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About Javier Colomer
Javier Colomer
"Knowledge Makes Stronger", Javier Colomer's motto, sets out his clearest statement of intentions expressing his knowledge and fitness experience.
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