One of the most under-managed and as a result under utilised components of resistance training is time under tension. Even those that factor it in as a variable to their programme design, often fail to understand the significance of the term or its real world application.
The purpose of this article is to explain what time under tension actually means from a practical perspective, what the significance is from a coaching standpoint and how it can be manipulated to produce different training or hormonal outcomes.
What is Time under tension (TUT)?
From a truly technical standpoint, time under tension refers to the length of time a muscle is active (i.e. under tension) during an exercise. This is usually calculated by multiplying the number of repetitions by the time taken to perform each rep. For example, if the tempo for an exercise was 3010, that would represent a 3 second eccentric, followed by a 1 second concentric, which in turn would result in a 4 second rep. Therefore a set of 10 repetitions would give a time under tension of 40 seconds.
The Practical Significance
Although technically a set of ten repetitions using the above tempo would generate a time under tension of 40 seconds, many clients will rush both the eccentric and concentric phases, so it’s important to ensure they stay on the count. It’s also important to ensure that there are no pauses during the movement, as whilst technically under tension, the active muscles can actually reduce their involvement in the exercise slightly.
One possible strategy that is incredibly effective at helping clients to adhere to a given tempo is the use of a metronome set to 60bpm. Not only does this ensure consistency from rep to rep, but it also helps clients to even out their movement by helping them break it into manageable and quantifiable sections.
It is also important to stress the importance of focussing the effort on the target muscles, as purely from a biomechanical standpoint, there are often many ways to elicit the same overall movement. The simple act of consciously and exclusively trying to use a particular muscle can change the clarity of the signal from the brain to the body and result in a greater level of activation.
Manipulating Time Under Tension
The following times under tension are commonly accepted, although it is important to recognise the need for varying stimulus and progressive adaptation.
|1-20 seconds||Power and Relative Strength (strength gains without an increase in size)|
|20-40 seconds||Functional Hypertrophy (gains in strength and size)|
|40-70 seconds||Hypertrophy (size gains independent of strength)|
|50 seconds or more||Endurance|
Therefore an athlete looking to increase their strength, without increasing size, should have a time under tension of no more than 20 seconds for any given exercise.
The above figures represent typical best practice, rather than absolutes. All rep ranges and all TUT’s can have value. The key to maximising client progress is to ensure that the main portion of their workout is spent in or around the sweet spot.
For example, in an accumulation phase (increasing work capacity) a client may perform 3 sets of 12 squats with a 3110 tempo, resulting in a TUT of 60 seconds per set, keeping them in the 40-70 second range. In a subsequent intensification phase (getting them stronger) they may perform 4 sets of 8 squats with a tempo of 4010, giving them a TUT of 40 seconds, again, keeping them in the hypertrophy dominant range.
Another important point to remember, is the relative intensity (percentage of a 1Repetition Maximum (1RM) for that exercise), will in part determine the rep range. For example, 15 repetitions on a 1010 tempo is unlikely to achieve much of anything if the weight used only represents 25% of the individuals 1RM.
One final observation worth considering with regards to training women, is that because of their lower levels of the androgenic (male) hormones, hypertrophy training protocols tend to increase fat-loss rather than building muscle, provided the rest periods are kept to no more than 60 seconds between sets.