If you’re a regular gym goer and you’ve not heard of time under tension training, well, it’s time you slowed down and got on it. Here’s a guide to all you need to know. 

Timing is a huge element of your training. The time of day you chose to work out can impact your performance, while the amount of time you rest between sets influences fatigue and recovery. How long it takes you to perform each rep also matters. Many of us bounce through our exercises quickly, but slowing down could actually have huge benefits. That’s because your muscles will be under load for longer, known as increased ‘time under tension’. 

“Time under tension (TUT) training is all about moving slowly through either part of your reps, or the entire rep,” says Jess Rosart, gym manager and coach at WIT House. “Take a back squat, where you might lower down for one count and then press back up for one. Increasing TUT to lower for three and rise for three makes it a six-second exercise, tripling how long your body is under resistance.” 

TUT is an element of training volume – that is the total amount of work done over a period of time. There are lots of other things that factor into workout volume, but when it comes to TUT the general idea is that if you can lift 20kg for three seconds, you’ll be doing more work than if you lifted 20kg for one second. So is it the under-the-radar way to progress in the gym? 

The benefits of increasing time under tension

The most exciting benefit of slowing down your reps seems to be that it can enhance hypertrophy. According to a study from the Journal of Physiology, lifting and lowering for six seconds each rep improved muscle protein synthesis (which leads to muscle growth) more than performing the reps for one second up and down, even when both groups worked to fatigue. 

The extra muscle growth is probably because you spend longer in the eccentric phase, or the lowering phase, of the movement. “This is the part many people find easiest,” says Rosart. “For instance, it’s easier to lower into a squat – the eccentric phase – than it is to get out of it – the concentric phase. If all of the exercise is equally challenging, it will lead to more muscle fatigue.”

And the eccentric phase is also where the most muscle is built. In a 2021 review into time under tension training, published in Sports Medicine, researchers wrote that increasing the time under tension during eccentric movements “increases metabolic stress, hormonal responses and muscle tension, which are thought to be important factors implicated in the promotion of muscular hypertrophy.” 

TUT might also enhance muscle growth as it aids mind-to-muscle connection. Rather than racing through reps, going slow allows for better awareness and control. Research published in the Strength and Conditioning Journal found that intentionally focusing on the target muscle increases activation. While it’s not yet known whether activation translates into muscle growth, early research indicates that this may be the case. 

“The slower pace also reduces the risk of injury in the long term by building better stability and balance as you control yourself through the movements for longer periods of time,” adds Rosart.

How to choose the right tempo for increasing time under tension

TUT sounds appealing, but choosing the right tempo and speed are important. A 2021 Sports Medicine review found that the optimal TUT for muscle growth should be 20-70 seconds. With the hypertrophy rep range being eight to 12, that means each rep should ideally last between three to nine seconds.

You don’t need to spend the same amount of time in each phase of the exercise. Remembering that the eccentric phase is associated with most muscle growth, you might choose to lower for longer than you lift. “I like to follow a 3-1-1 tempo in exercises; lowering for three, pausing for a second at the end of the move, then exploding out of it quickly,” says Rosart. 

The science does suggest that there can be too much of a good thing though. According to a 2015 study, performing a rep for more than 10 seconds negatively impacts hypertrophy, so stop short of spending too long lifting. 

The best exercises for time under tension training

TUT training can be done with any exercise that involves resistance, including bodyweight and weighted moves. The key is control: you need to be able to move slowly through the reps without compromising on form or wobbling around. 

Rosart likes adding time under tension to bodyweight exercises like push-ups and pull-ups. Again, focus on the eccentric portion before lifting back up. Or, for those who can’t yet nail a whole rep, step back to the top of the exercise. The eccentric TUT will help you build the muscle you need to eventually achieve a full rep.

Many of the studies on TUT training use compound exercises, like squats or bench press. As these exercises are already great options for building multiple muscle groups at once, it makes sense to enhance their outcomes by using a slower tempo. Machine exercises, like leg extensions, are also commonly used when tempo training as it is easy to control the reps while you slow down the movement. 

5 things to know about time under tension training

Check your weight

Because TUT is harder than faster reps, it is advised that you drop your weights or your reps. Be smart when doing this – these are factors of volume, and going too light can reduce the impact of hypertrophy, even if TUT is maintained. 

Perfect your form

Good form is always important, but getting the right technique is crucial if you are spending longer in a position. “Going slow means you can think about the movement patterns, but always choose exercises that you are confident and stable in,” adds Rosart. 

Take care with DOMS

Eccentric training isn’t only associated with muscle gain but also increased DOMS. If you are extending the lowering phase of your exercise, expect to feel a little sorer. Focus on recovery by getting an early night for extra sleep, nailing your nutrition and doing some gentle stretches to ease the pain. 

Link the breath

“I think a lot of people miss this opportunity but linking your breath with your movement can really help when adding TUT,” says Rosart. “Breathe in at the beginning of the movement, hold it as you lower the weight and exhale to bring it back to the starting position.” 

Count your time under tension

In a 2015 study, researchers found that most people didn’t follow the proper timing of prescribed TUT training when doing it by themselves without the eye of a trainer keeping them in check. 

The study was too small to suggest that everyone will inevitably end up racing through their slow moves, but it’s a good reminder to check you’re not rushing. Go slow and your body will reap the benefits.