Varying Time Under Tension

  13 mins read  

Time to touch on a totally different subject than the previous post.

The objective of this post is to examine several ways of varying time under tension (TUT), and analyze the pros and cons of each method. It’s is essential to keep in mind that the concept of time under tension applies mainly to training for hypertrophy, and not strength training.

Let’s first look at what time under tension is and the goal that it tries to achieve.


TUT is the idea of maintaining tension in a given muscle group for a specified period of time. Instead of just flailing around and doing 3 sets of 12 reps, TUT says to keep tension in the muscle from anywhere between 40 and 80 seconds for a single set. Having tension in the muscle for such an extended period of time allows us to maximize the extent of micro-tears caused by weight lifting.

So what’s wrong with doing an exercise for the standard 3 sets of 12 reps? Nothing at all if you’re doing it right. However, most people tend to perform repetitions too quickly, and this limits the amount of hypertrophy that can occur. This is especially true on the “eccentric” phase of an exercise where beginners tend to let the weights drop instead of controlling them throughout.

TUT remedies this issue by focusing less on the number of reps and more on how the reps are performed. By adding a further constraint that says each rep should last 4 to 6 seconds, workouts will surely become more intense, the pump achieved will feel better, and a lifter’s time is better spent.

Different Rep Styles

Now that we recognize the important of TUT, let’s see how we can acheive that 40 to 80 second tension goal via different styles of reps. We need these basic styles to later on explore how to have variability in TUT.

Concentric Focus Reps

The way I perform these reps are for a count of 3 seconds up and 1 second down (4 seconds for a single rep). For example, when doing a bicep curl, it takes 3 seconds to lift the weight from the bottom to the top, and 1 second to control it back to the bottom position. By doing 10-15 of these reps, the TUT for a single set ranges from 40-60 seconds.


  • Reps only take 4 seconds
  • It’s easier to squeeze a muscle on the way up than on the way down


  • The eccentric portion is performed a little to quickly

Eccentric Focus Reps

The way I perform these reps are for a count of 1 second up and 3 seconds down (4 seconds for a single rep). For example, when doing cable pushdowns, it takes 1 seconds to push to rope down to the fully extended position, and 3 seconds to control it back to the starting position. By doing 10-15 of these reps, the TUT for a single set ranges from 40-60 seconds.


  • Reps only take 4 seconds
  • Challenges muscles differently than they’re used to in everyday activities


  • It can be difficult to utilize the right muscle group on the way down
    • For example, on bicep curls it feels like my forearms play a bigger role in the eccentric phase than the concentric phase
  • Doesn’t work well with resistance bands since tension is progressively reduced on eccentric phase

Isometric Hold Reps

This is one of my favorite rep styles because it exhausts muscles in a way that feels different than the previously mentioned styles. The fight against gravity for isometric reps feels more difficult in part because the reps last longer and also because there is an absence of any sort of rhythm. The general way these reps are performed is for a count of 1 second up, a 5 second hold, and 1 second back down. However, the hold can vary anywhere from 3 to 8 seconds.

There are a few exercises that require special attention for these kinds of reps in terms of what part of the range of motion the isometric hold should be performed.

  • Bicep Curls
    • I perform the isometric hold at halfway between the top and bottom of the range of motion. The reason for this is that there isn’t much tension at the top of a regular bicep curl (I guess that’s why incline curls were created)
  • Chest Flys
    • Whether I do these with dumbbells or cable crossovers, I perform the isometric hold at the “top” of the exercise
  • Chest Presses
    • I perform the isometric hold halfway between the top and bottom of the range of motion. The motivation is similar to that for bicep curls
  • Bent Over Rows
    • Performing the isometric hold at the top of the exercise works well since there is plenty of tension at that point
  • Lat Pulldowns
    • Performing the isometric hold at the fully contracted position works well for me since it helps me focus on engaging the lats


  • Can improve the mind-muscle connection by focusing on squeezing the muscle
    • After all, it’s tough to use momentum when performing an isometric hold
  • Creates the strongest sensation of soreness and burn
    • This is also due to the absence of momentum


  • If sticking to the 8-12 reps range, these reps can significantly increase the length of a workout
  • These reps have to be wisely scheduled within a workout
    • Doing sets of isometric reps at the beginning of a workout can make the muscles feel very fatigued, and this can reduce the benefit obtained by exercises later on

Defining Variability

For most experienced lifters, the previous section was probably review. Now we get to fun part where we see how to make things more interesting. We need to define two types of variability that can exist in a workout. Note that there is one more type of variabiliy that will be covered in a later post.

Between-Set Variability

This is the easiest variability concept to grasp, and it’s also the easiest in terms of implementation.

Blocks of Sets

Workouts are normally divided into blocks of sets where each block can be made up of anywhere from 3 to 8 sets. Blocks help us group related exercises and muscles together. For example, a block can be focused on alternating between chest and back, or it can be focused purely on chest or purely on back. It can also be focused on certain styles of exercises; a block might have all bodyweight exercises, all cable exercises, or all dumbbell exercises to name a few styles.

Let’s use the following chest and back block as a running example

Notice how the block alternates between chest and back. I like to have most of my blocks like this since it minimizes the time spent sitting around and waiting for the muscles to recover. Since we have 6 sets in this block, there are many ways in which we can add variability between sets. We will use the following color scheme to denote concentric, eccentric, and isometric sets

Let’s see a few basic methods and analyze them a little

Alternating E-C

Since we have an even number of sets (6) in the block, this method is biased because the chest is being worked only with an eccentric focus while the back is being worked only with a concentric focus. A block like this should be followed by another similar block where the chest is being worked with a concentric focus and the back with an eccentric focus.

This is about as basic as it gets and it is an easy pattern to remember while doing a workout.

Eccentric then Concentric

This method is slightly less biased since only 2/3 of the time chest is being worked with an eccentric focus, likewise for the back. In this case, the choice to follow up with another block where the chest is being worked with an concentric focus 2/3 of the time, likewise for the back, is optional.

This is also easy to remember and has slightly more variety per mucscle group than the previous method.

Iso Sandwich 1

Now comes the fun part. The first three sets make a sandwich of the form eccenctric-iso-eccentric, and the last three sets make a sandwich of the form concentric-iso-concentric. The bias here is obvious since there is more eccentric work for the chest and more concentric work for the back. However, both muscle groups are being worked in an isometric way for a set. Thus, variability in set types per muscle groups easily surpasses that of the previous two methods.

Remembering this method is tricky since you have to keep in mind to go from eccentric to concentric for the second sandwich in the block. Nevertheless, the sandwich structure will keep you on your toes and the variety should have a plateau-busting effect.

Iso Sandwich 2

This is considerably more difficult than all the other methods plainly because of the sheer amount of isometric work being done. Surprisingly, this method works both muscle groups evenly with 2 isometric sets and 1 concentric set for both the chest and back. Again, notice how the first 3 sets form a sandwich, as well as how the second 3 sets form a sandwich.

Remembering this method is slightly easier than the previous style of iso sandwich, so that’s a slight advantage. Keep in mind that you’ll probably have a workout sheet with you reminding you of the style of each set, but when you’re pushing as hard as you can in the middle of a workout, it can be easy to misread what’s written on the sheet and just repeat what you did for the past couple of sets.

I reccommend only having one of these blocks in an entire workout, preferrably near the end because it will take a serious toll on the muscles.

Within-Set Variability

We just saw a few ways of creating variability between sets, but what on Earth is variabiltiy within sets? Well, it should come as no surprise that it involves changing up how you perform reps within a set! This is best demonstrated with a few examples.

Eccentric Buildup Sets

This set style involves performing reps with increasingly longer eccentric portions, going back to the first rep duration, and repeating this process. Let’s illustrate this so that it makes more sense.

We first define a color legend so that the set will be easier to interpret. The legend labels such as “1U-2D” are to be interpreted as 1 second up and 2 seconds down.

This legend forshadows that the number of reps within the set will be a multiple of 3. Here is what an eccentric buildup set of 9 reps looks like.

The great benefit of this type of set is that it allows you to experience several durations of the eccentric part of a repetition all within a single set.

Concentric Buildup sets

Just like eccentric buildup sets, except that the concentric part of repetitions is performed for increasingly longer durations. Let’s make it explicit to avoid any confusion.

We define another color legend to denote the duration of every rep within the set.

We look at what a concentric buildup set of 9 reps looks like.

Concentric buildup sets give you the change to experience several durations of the concentric part of a repetition all within a single set.

Alternating Iso Sets

It’s sometimes the case that regular isometric sets simply take too long. To remedy this issue, we turn to alternating iso sets. An alternating iso set means that we alternate between performing normal reps and performing iso reps thereby halving the number of iso reps. There are two ways that we can do this.

As always, a picture does more justice than a description.

The last color legend of the day is read as follows: “2U-2D” means 2 seconds up and 2 seconds down; “1U-5H-1D” means 1 second up, a 5 second hold, and 1 second down.

As you probably guessed, it’s best to have an even number of reps when doing an alternating iso set, so we look at sets with 8 reps in them.

As you can see, using either type of alternating iso set, the number of iso reps is halved. This is a great compromise between regular reps and iso reps, and the benefits of both rep styles are realized within a single set!


We saw that it is good to make use of concentric, eccentric, and isometric reps. All of these have their advantages and disadvantages, but maintaining a balance of them within a workout can make the performance of your muscles be more well-rounded. Introducing these rep styles has a plateu-busting effect, and can help improve form and mind-muscle connection.

We also looked at how to create between-set variability by assigning different rep styles to sets within a block. Lastly, we saw how to create within-set variability by changing how we perform reps within a set.

Given these two tools, you should be able to add a significant amount of variability in TUT in your workouts. The ideas here are only a sample of what’s possible, so be creative and add in your own styles for the best results possible.

As always, stay tuned for more knowledge!