Despite playing a critical role in building muscle, time under tension and how it affects muscle growth is rarely given the recognition it deserves.
While the likes of high-intensity interval training (HIIT), weightlifting, and high-protein foods may steal the spotlight, this unglamorous but effective training principle has underpinned strength training since the day on. the first free weight was made. And it’s still important in modern home workouts, like when using the best adjustable dumbbells (opens in a new tab).
But what does time under tension mean? In short, it’s the total time your muscles are working during the exercise and this is dictated by the number of reps you complete in each set as well as the speed at which you complete them.
Varying the time under tension can alter the stimulus of a workout, helping you focus on different facets of fitness, such as muscular endurance, hypertrophy (opens in a new tab) or muscular strength, says Jinger Gottschall, director of applied research at Wahoo Sport Science (opens in a new tab).
We spoke extensively with Gottschall and examined relevant studies to explore how you can manipulate time under tension to get the most out of your workouts.
Jinger S. Gottschall earned her doctorate in integrative physiology from the University of Colorado at Boulder and continued her academic career as a postdoctoral fellow in neurophysiology at Emory School of Medicine. She was an associate professor at Pennsylvania State University and studied the efficacy of various exercise regimens for 12 years. For the past 25 years she has coached endurance triathlon and running athletes from the recreational to professional level. Most importantly, Jinger has a passion for physical activity and appreciates the paramount importance of promoting quality and balanced training programs.
What is time under tension?
Time under tension is simply the amount of time a muscle is under tension during a workout.
This includes the eccentric and concentric parts of an elevator; the lengthening and shortening of the working muscle. For example, while most of your effort is used to push a barbell bench press up and away from your chest (the concentric phase), your pectoral muscles will still be under tension as they control the descent of the bar (the concentric phase). eccentric phase).
Some time-under-tension manipulations (or tempo training) can also use an isometric contraction. This is where the length of the muscle does not change during the contraction; for example, when sitting against a wall, where you remain motionless but the leg muscles are still under tension.
Does time under tension build muscle?
For anyone who wants to discover how to gain muscle (opens in a new tab)It is no exaggeration to say that, without some element of time under tension, muscle gain (or hypertrophy (opens in a new tab)) in adults would be almost impossible.
“Muscle hypertrophy occurs when muscle protein synthesis outstrips muscle protein breakdown and results in a positive net protein balance over cumulative periods,” summarized a 2019 study published in the journal International Journal of Environmental Research and Public Health (opens in a new tab). “This could be achieved with both resistance training and protein intake, which stimulates muscle protein synthesis and leads to a decrease in muscle protein breakdown.”
In other words, you need to do some form of resistance training (like lifting weights or using some of the best resistance bands (opens in a new tab)) and eating enough protein if you want to grow your muscles. And during that resistance training, your muscles will need to be under tension for a while.
How does time under tension affect performance?
In gyms around the world, people follow the rough advice of:
- Do heavy sets of four to six repetitions to gain strength.
- Complete eight to 12 repetitions with a moderate weight to build muscle.
- Do 12 or more repetitions with a lighter weight to improve muscular endurance.
Time under tension is the principle behind this. To think:
- If you perform four bicep curls with a two-second eccentric (down) phase and a one-second concentric (up) phase, your biceps will have been under tension for a total of 12 seconds.
- If you perform 12 bicep curls at the same pace, this number increases to 36 seconds.
However, please ignore this as “brother science” at your peril.
“It’s critical to overload the muscle in a way that challenges it toward its goal,” says Gottschall.
But, he adds, the tempo and rep scheme you lift with (both critical factors in deciding your total time under tension) will determine which facet of fitness your training goal is.
“If you want to gain muscular endurance then use lighter weights for a higher number of repetitions with a slower speed until volitional fatigue; in this case, volitional fatigue is the inability to continue due to muscular resistance. If you want to gain muscular power, use heavier weights for fewer repetitions completed at a faster rate to voluntary fatigue.”
Therefore, lifting lighter weights for more reps to create more time under tension can help build muscular endurance, or a muscle’s ability to repeatedly exert force against a load over a prolonged period.
Meanwhile, lifting heavier weights with fewer reps to create less time under tension overall can help increase an athlete’s muscular power—the ability to produce explosive force over a short period of time.
How long under tension for hypertrophy?
Both of the examples listed above focus on lifting light weights at a slower pace to improve muscular endurance or lifting heavier weights at a faster pace to build muscular power. To gain muscle, a happy medium must be found between the two factors. Gotschall recommends adding weight or repetitions to his usual exercises.
You can also introduce tempo training, where you vary the timing of the eccentric, isometric, and concentric phases of your lifts, to challenge your muscles with new stimuli.
“Spending more time in the eccentric phase of the movement increases the time under tension,” says Gottschall. “And several studies reported that low-load training results in hypertrophy similar to moderate and high-load training when training to voluntary fatigue.”
Still, Gottschall says it’s difficult to draw an exact figure for the optimal amount of time under tension for muscle growth from the existing literature.
A 2011 study published in The Journal of Physiology (opens in a new tab) found that leg extension exercises performed at a slow pace (a six-second eccentric and concentric phase) and performed to fatigue produced a greater increase in muscle protein synthesis than the same movement performed quickly. However, a 2015 study published in the Sports medicine (opens in a new tab) journal contradicts this, concluding that the observed muscle hypertrophy was similar in a study group when training with multiple repetitions lasting between 0.5 seconds and eight seconds.
So what type of training should you aim for if hypertrophy is your goal? A 2019 systematic review published in the International Journal of Environmental Research and Public Health (opens in a new tab) advises that anyone who wants to maximize muscle growth should do 3 to 6 sets of an exercise, with each set of 6 to 12 repetitions. Sets should be broken into 60-second rest intervals. And drop the light weights – you should aim for a moderate intensity of 60-80% of your 1RM.
Do you want to keep growing? Then increase your training volume from 12 to 28 sets for each muscle, each week.
