Is it necessary to keep “constant tension” on the muscle during your sets in order to maximize hypertrophy? This article provides the answer.

“Constant tension” is a common bodybuilding term, where to stimulate maximum muscle growth, the muscle needs to be kept under continuous tension throughout the entire set. 

Rather than lifting and lowering the weight through the fullest range of motion possible, constant tension refers to stopping a bit shorter at the top and/or bottom end of the lift. This eliminates the point of rest, so the tension stays on the muscle at all times. 

Some examples of this include stopping a few inches short of lockout rather than pressing through on a chest or shoulder press, or leaving a few inches at the top of each rep to prevent the quads from resting on a leg press. 

Due to the fact that there is some mixed research on constant tension, it is a much-debated issue. Here’s my viewpoint based on muscle growth’s overall logic and my own experience, observation, and research.

What stimulates muscle growth?

When it comes to muscular hypertrophy, the most important factor is training your muscles close to or up to their maximum strength capacity on each set. This means that you’re training hard and getting close to muscular failure, regardless of the specific lifting style you use to get to that point. 

You want to get yourself to the point in the set where you’re on those last few demanding reps and you’re exerting yourself against the weight with maximum force. When the muscle is being challenged close to the point of failure, this ultimately stimulates muscle growth. 

I would aim for at least three reps short of failure as a minimum if you want to make significant gains, and ideally 1-2 reps short on the bulk of your sets. You can also mix in some sets all the way to complete failure here and there as well.

Muscle growth as an adaptive response

Muscle growth is an adaptive response to an environmental stressor. It’s evolutionary, and it’s built into our DNA. 

If there’s a task in the environment that you need to complete but your muscles can’t do it, the muscle-building mechanism gets triggered, and your body makes proper adaptations to suit itself to the environment better. 

If one of your ancestors needed to climb a tree to get some fruit to survive, but their lats and biceps weren’t strong enough to pull themselves up, their body would have responded by increasing the size of their biceps and lats so that next time they’d be able to climb up and get the fruit. 

Whether they tried to pull themselves up that tree using “constant tension” or not, they were trying as hard as they could to complete some physical task without achieving it, which incentivizes the body to grow new muscle. 

This also applies in the gym, as the gym is just an “artificial” construction we use to trigger that evolutionary response in a controlled way. Whether you get yourself close to failure using constant tension reps or just “regular reps” where tension might leave the muscle momentarily at certain points in the range, that will not make a noticeable difference to your bottom line gains in the long term. 

As long as you perform a high enough volume of total reps that are done close to failure, and you’re slowly adding more weight to the bar over time or using other methods of progressive overload, your body will have no choice but to adapt further, and new muscle will be built in response to that. 

Ultimately, gaining muscle boils down to training close to failure and then continually challenging your muscles with a higher workload over time.

What’s the difference between using constant tension reps vs. non-constant tension reps?

When you do an exercise in a constant time under tension style, the muscle never has any chance at all to rest, so it doesn’t get that momentary “release” at the top or bottom of the rep. 

This is going to cause a greater pooling of blood and metabolic waste products in the muscle, making a load more challenging, so you’ll end up reaching muscular failure using a lighter weight

This is similar to blood flow restriction (BFR) training, where you’re physically wrapping bands around your arms or legs to trap that blood and those metabolites inside the muscle. With BFR training, you’re able to lift a lot less weight. 

The research shows that even going as low as 20-30% of your one-rep max produces the same amount of net muscle growth compared to regular heavy sets, as long as you train close to failure. 

With BFR training, while the feeling of tension on the muscle (the pump) can feel incredible, it doesn’t produce better growth than regular straight sets. (Study 1, Study 2, Study 3, Study 4). 

Constant tension is middle ground training

Constant tension training is like a middle ground between regular non-constant tension reps and BFR training. 

You’re adjusting the way you perform the exercise to make a given load more challenging, which causes you to reach failure more easily with lighter loads, assuming you’re only shortening the range slightly. 

However, as long as the proximity to failure is equated, the bottom line hypertrophic response will be the same since all your body cares about is the total percentage of that muscle’s momentary resources that are being used up. 

If you get to the point in the set where you’re using up 95% of what that muscle is ultimately capable of, then it doesn’t matter how you got there, and the hypertrophic response will be the same. 

Otherwise, it’ll be very similar, and even if it does lean slightly in one direction or the other, it’s not going to matter in the long run. When comparing different rep ranges as well, the same thing is observed. As long as you get close to failure, low, medium, and high reps all stimulate comparable hypertrophy. 

While it might feel like higher rep sets are putting more tension and stress on the muscle, it just comes down to getting close to failure.

Do bodybuilders focus on constant tension?

The majority of big, strong, natural lifters that I’ve observed over the past 20 years, including myself when I was at my biggest and strongest maybe 10 years ago, do not worry about constant tension. 

Instead, they’re training hard and doing basic compound lifts with proper form, while focusing on progressive overload. If the muscle tension happens to decrease for a brief moment at some point in the range, it’s not some limiting factor. 

The best example is a barbell squat. Many lifters out there have built massive legs with barbell squats as their primary movement, and they do almost nothing except squats. Yet, heavy barbell squats are one of the least “constant tension” movements. 

In the top position, when you’re standing upright, there’s no tension on your quads at all. You spend a more extended period “resting” between reps compared to other exercises because you have to reset at the top of each rep by breathing out, taking another deep breath back in, and bracing your core before you descend again. 

This is the same for deadlifts, too, except just in the bottom position. Or on a Romanian deadlift, where there’s no tension at the very top. 

The pecs aren’t working significantly at the top on a barbell or dumbbell press since gravity is pulling the weight straight down, and the pecs exert their force in an arching motion. There’s often a slight rest at the bottom on an overhead barbell press, depending on how you’re doing the movement.

These are just a few examples of how many people have built strong, muscular physiques using these basic lifts as their core workouts. 

Most of the people who use constant tension tend to be enhanced bodybuilders. If you look at how many pro bodybuilders train, they often utilize a constant tension style of training. 

This causes people to think that’s the best way to train, without realizing that someone who is using performance-enhancing drugs and has top-tier genetics will grow insanely well no matter what they do. This growth is not directly because they’re training with constant tension.

Does more time under tension increase muscle growth?

If you want to maximize muscle growth, it doesn’t matter what training style you employ as long as you’re doing enough total reps close to failure. 

If you’re a novice, then train the basic lifts using the fullest range of motion you comfortably can, and if there’s a brief moment in the lift where the tension decreases, it’s not going to hurt your gains. 

As you become more experienced, you can start experimenting, and if you find that on certain lifts using more of a constant tension style feels better for you, then that’s fine. 

Again, the most important thing is getting close to failure. While you should  strive to put the muscle under tension throughout the largest overall range that you can during an exercise, if the tension momentarily leaves the muscle at the top or bottom end of the range you are using, it’s not a big deal.

The benefits of constant tension 

The one potential benefit of constant tension training is that it might reduce your joints’ stress since it allows you to get close to failure using a lighter weight. 

For example, if you have some shoulder discomfort on chest presses and you find that it goes away by lightening the weight a bit and not pressing up, then that might be a perfectly valid approach for you. If you have a lower back issue, a leg press while stopping several inches short of a lockout may help you reach failure in your quads while using less weight. 

Similarly, if you have elbow discomfort on a biceps curl, the weight can be dropped down, and a couple of inches can be cut out of the top and bottom end of the range. This would be the main practical application of constant tension training. 

Like with BFR training, it’s just a way to get the same net training effect but with less weight, so if you prefer constant tension style training, that’s completely justifiable.

Final thoughts

While constant tension is a perfectly acceptable technique, training to maximum muscle strength capacity while being close to or at muscle failure is the most crucial factor regarding muscle growth. 

Constant tension can be incorporated into your routine depending on your preferences and abilities; however, it’s not going to cause any noticeable change in your gains if all else remains equal.

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