When it comes to muscle growth, time under tension is a hot topic. Many people believe that if you want to see results, you need to focus on keeping the weight under tension for 30-60 seconds per set at a time. However, recent studies have shown that training for muscle failure may rather be the key to seeing results – regardless of time under tension or speed of movement.
It is often said that extending the amount of time your muscles are under tension can lead to more muscle growth, and some people suggest that the optimal time range for maxing out hypertrophy is 30-60 seconds. Today, we will not only look at the scientific evidence supporting this claim but also the scientific rebuttals to it.
We will try to establish whether there are minimum and maximum thresholds for a time under tension and whether slowing down only the lowering phase of an exercise could be beneficial.
So let us dive into the discussion of what time under tension is and whether or not it matters for muscle growth. Stay tuned!
What is Time Under Tension?
Time under tension means the time that you will need to perform one repetition of an exercise.
So you could do 10 bench presses with a certain weight really fast with a very short time under tension or you could perform the same number of repetitions at a very slow movement speed. By doing so, you would do the same amount of reps, but your time under tension would increase massively.
The common conception that has been preached over and over again is that a long time under tension would trigger a massive metabolic response and kick off muscle hypertrophy.
The reason for that result is thought to come from the idea that an elongated time under tension would put more strain on a muscle and thus maximize muscle growth.
Basically, time under tension is very important indeed – but there are more things that have to be factored in.
What triggers Muscle Growth?
Building muscle needs a few prerequisites in order to take place. First, you need to do strength training – or resistance training, whatever you want to call it.
You need to put a strain on your muscles which will trigger a metabolic response and tell your body to adapt to the new circumstances by building more muscle tissue.
That is why a repeated exercise routine in combination with the right resting periods will lead to more adaption of your body.
Then you need the right nutrition to support the muscle-building process. The uptake of enough protein is essential for your gains.
We have elaborated on the topics of whey protein vs plant protein in this article here. And we also showed how creatine works in this article if you would like to check them out.
Basically, if you want to support muscle hypertrophy you will need an increased amount of protein.
The right amount of sleep is also one very important building block of your muscle-building efforts. You can find an article about this topic right here.
If we did all these things right, we will maximize our chances of properly kicking off muscle protein synthesis.
What Science says about Time Under Tension
Scientific studies have been made on this topic – for example, a Canadian study by Nicholas A Burd et al that was published in “The Journal of Physiology” examined the effects of elongated time under tension when doing the same exercise.
The exercise used was leg extensions – 3 sets at 30% of the one rep max.
The study came to the conclusion that muscle protein synthesis 24 to 30 hours after the exercise program was higher among those who used a six-second lifting and six-second lowering movement pace. In comparison to that, the one-second lifting / one-second lowering group showed less muscle protein synthesis.
Of course, the time under tension for the six-second-group was much higher…
More studies have been done on time under tension – for example by Yuya Watanabe et al: Increased muscle size and strength from slow movement, low-intensity resistance exercise and tonic force generation
They had two untrained groups of men perform strength training sessions where they had to do 3 sets of leg extensions and leg curls for several weeks.
This study also came to the result that a long time under tension – 3 seconds lifting and 3 seconds lowering versus 1-second lifting and 1-second lowering had positive effects on building muscle.
Most studies on the topic of time under tension during resistance exercise came to this very same result.
So one might think that simply applying a slower speed to one’s usual workout plan will be the magic key to success.
But it is not that easy…
Training for Failure
Rethink Time Under Tension Workouts
What most of the above-mentioned studies did not take into account was muscle fatigue or training for muscle failure when doing resistance training with slow movements.
They simply assumed that performing a tut training (time under tension training) with elongated time under tension periods resulted in positive results because of this elongated time under tension.
But if you think about it logically, you will recognize that the – very important – part that muscle failure plays in that whole game has been neglected:
Imagine yourself doing bicep curls with a weight that represents about 40% of your one rep max.
Imagine you perform a set with 8 reps rather quick – 1-second up, 1-second down… This set is done after 20 seconds and you might feel a little muscle burn but you are far from complete muscle fatigue or even muscle failure.
Now imagine you perform that same set at a slower tempo – let´s say 3 seconds up, 3 seconds down.
This time you will reach muscle failure, or you will come close to failure.
Maybe Muscle Failure Optimizes Muscular Strength?
According to most of the existing studies, you should benefit because you applied more mechanical tension using slow-tempo training.
But is that really true?
Or did we benefit because we came much closer to muscle failure as a result of our slow-tempo workout?
Simply asked: is training for muscle failure perhaps more important than time under tension?
There is an evidence-based approach to that question: these three studies are representative of a larger number of similar studies that all come to the same conclusions:
- Talisson Santos Chaves et al: Effects of resistance training with controlled versus self-selected repetition duration on muscle mass and strength in untrained men
- Lucas Túlio Lacerda et al: Resistance training with different repetition duration to failure: effect on hypertrophy, strength and muscle activation
- Brad J Schoenfeld et al: Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis
The main takeaway from these studies was:
- As long as a test group trained for muscle failure – regardless of the speed of the single repetitions – both of these groups showed similar results in muscle growth! So it doesn´t matter if you train for muscle failure using a tut method or do more reps faster!
- Weight doesn´t matter either! As long as you train for muscle failure it doesn´t matter if you perform a smaller number of reps with heavier weights or if you perform a higher number of reps with lighter weight! What counts is your effort to train until you come to or close to muscle failure!
Let´s think that through
If we think about this logically again, we will see that time under tension with lower weights until reaching muscle failure is much longer than it is with heavier weights. Yet, each exercise program yields the same results!
So training to muscle failure seems to outdo time under tension!
Concentric vs Eccentric Movements
So what about another mantra: “It is the eccentric phase of a movement pattern that lets muscles grow!”
Every movement pattern consists of a concentric phase (the contraction of a muscle) and an eccentric phase (the extension of a muscle).
Eccentric movements, which involve lowering a weight slowly and under control, are thought to be effective for promoting muscle growth. During eccentric movements, the muscle fibers are placed under significant tension, which can help to trigger the process of muscle hypertrophy. Additionally, eccentric movements can help to increase muscle strength and improve overall athletic performance.
There is evidence from several studies to suggest that eccentric movements can be effective for promoting muscle growth. For example, one study published in the Journal of Applied Physiology found that eccentric training was more effective at increasing muscle size and strength than traditional concentric training. Additionally, a meta-analysis published in the Journal of Strength and Conditioning Research concluded that eccentric training can lead to significant increases in muscle size and strength. However, it is important to note that the effects of eccentric training may vary depending on the individual, and more research is needed to fully understand its potential for muscle hypertrophy.
Movement Quality Matters
We tend to keep adding weight to every exercise set. Heavy weights equal to massive strength gains for many gym-goers.
But in fact, most of the time heavy weights kill proper form!
A vast number of athletes perform their workouts unsupervised by a coach who gives them at least initial instruction on how to perform complex exercises correctly.
The result for many are workouts that are performed with as many reps as possible and with zero muscular control but catastrophic form.
So the idea of performing an exercise with a maximized time under tension results in slow movements which in return help to prevent injuries.
So time under tension in this context has a quite positive effect.
Be Careful When Training to Muscle Failure!
Training to muscle failure can be a demanding form of exercise, and it may not be suitable for everyone. It is generally not recommended for people who are new to weight training or who have certain medical conditions. In particular, people with conditions such as heart disease, high blood pressure, or a history of stroke should avoid training to muscle failure. It is also generally not recommended for pregnant women or people who have recently had surgery. If you are unsure whether training to muscle failure is appropriate for you, it is important to consult with a healthcare professional or certified personal trainer.
The idea of time under tension and the benefits that a tut training has might need to be reassessed.
Studies have proven that training for muscle failure or at least close to muscle failure is much more important than observing strict time under tension values.