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Does Time Under Tension Matter?

Does Time Under Tension Matter?

In short, the answer is yes. It’s extremely important for any bodybuilder wanting to maximize muscle growth and fat loss. This newsletter provides a breaks down the science of Time Under Tension (TUT), explaining the physiological and cellular mechanisms which makes it SO important.

TUT describes to how long the muscle is under work or stress, often used per set or exercise. For example, 10 reps on bench press lasting 2 seconds down (eccentric) and 1 seconds up (concentric) would be 3 seconds per rep and therefore 30 seconds total TUT. It is also important to remember TUT does not always mean Time Under Load. If for example, you perform an exercise where the muscle is resting for part of the movement you will have less actual TUT than you think. When considering TUT always focus on the time under load, a bodybuilder wants to constantly place stress on the muscle from the first rep to the very last.

Research has shown in order to maximize hypertrophy or muscle growth, you want to keep the muscle under constant tension or stress, without any rest mid set. In contrast, for strength and power based exercise you often need or have very little TUT. If you look at deadlifts, a 3 rep set may only have 3 second TUT (1 second to drive up, then you drop and repeat). Now, this isn’t to say you would never grow from pure strength work as there are other mechanisms for muscle growth, although strength work alone is not optimal.

For a bodybuilder wanting to maximize growth, TUT plays a key role and they should likely combine all aspects of training (e.g. strength and hypertrophy work) in a block or periodized program. Although there is no universal definition, many class:

Low TUT: 0 – 30 seconds.

Medium TUT: 30 – 60 seconds.

High TUT: 60 – 120 seconds.


In short, the likely mechanisms of TUT is mechanical tension, cell swelling and metabolic stress.

During a prolonged set, with a large or lengthy TUT such as Kris’s DTP training you should feel an extreme “burn”. This is due to the production of metabolites, such as hydrogen ions. This along with the compression of blood vessels reduce the PH level within our muscle, known as acidosis. Furthermore, these cellular alterations may lead to an increase in Muscle Protein Synthesis which is a key process in muscle growth.

This type of training can also be awesome for fat loss, providing a metabolic stimulus and burning more calories. Although its significance is still being established, it can also increase anabolic hormones such as growth hormone (a potent fat burner) for a period of time after the workout.


Interestingly, supplements in PRE-KAGED®, such as Creatine HCI, Beta Alanine, Citrulline, Caffeine and Betaine (yes, that’s pretty much all of the ingredients!) will improve this type of training. You can get more details in this full PRE-KAGED breakdown however, here is a quick breakdown as to why:

Caffeine:Working via several mechanisms, increasing nervous system activation, resistance to fatigue and increase fat burning.

Beta Alanine: This supplement increases muscle carnosine levels which can help buffer the metabolites, allowing for more reps before failure.

Citrulline: Citrulline may help via the increase of L-arginine and improve resistance to fatigue.

Betaine:Betaine works as a nitric oxide booster and can also increase mitochondria efficiency and resistance to fatigue.

Creatine: By increasing muscle creatine stores it can help with the resynthesis of ATP energy. It can also help reduce acidosis.

Research has shown all of these supplements can reduce fatigue while “buffer” the metabolites and acidosis as described above. This allowing for more total reps, TUT and total volume, another key mechanism in muscle growth.


Research has supported TUT as a key mechanism behind muscle growth. Although some state it has less effect when total volume (weight lifted per session) is matched, this statement may not represent a bodybuilders regime.  Furthermore, the role of TUT has yet to be translated to bodybuilding high volume training that may involve techniques like DTP, giant sets, supersets etc. Although only speculative, these advance training techniques may show an even greater role of TUT in muscle growth.

Remember, although total training volume is a key factor, to match the total workout volume with more strength type training, it may take 3 hours instead of 45 minutes, this is impractical and probably not beneficial.


TUT is a key training variable you should utilize in your workouts. Although it is not the only tool for muscle growth, it will play a large role in bodybuilding type workouts. For your next workout, ensure you have some exercises or sets that have a high TUT at around 75 – 90 seconds. Remember to focus on continuous tension without pausing between reps, which may lose all the benefits of cell swelling and TUT.

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