If you’re serious about putting on size, you should know that the quality of your reps matters just as much as the quantity of them. One of the most effective — and simplest — ways to optimize your training and build muscle is to focus on time under tension.
What Is Time Under Tension?
Time under tension, often abbreviated as TUT, refers to the amount of time that your muscles spend “working” (lengthening and contracting) to resist an external load. You can prolong time under tension during an exercise by performing more reps and/or performing each rep at a slower pace, explains exercise physiologist Dean Somerset, CSCS.
Time under tension training simply focuses on prolonging the duration of each repetition of an exercise to promote muscle growth.
How Does Time Under Tension Build Muscle?
Bodybuilders have used TUT training for decades because it can stimulate hypertrophy, the growth and increase in size of muscle cells.
And if broscience isn’t enough to sway you, research published in The Journal of Physiology found that higher TUT produced greater increases in rates of muscle protein synthesis (the physiological process of building muscle mass) compared to lower time under tension.
Additionally, a research review in Sports Medicine reveals that slower movement tempos are most effective for hypertrophy when they focus on a slower eccentric (lowering) phase of an exercise.
This increase in muscle development can be explained by two factors: metabolic stress and mechanical tension.
“Longer TUTs tend to produce greater metabolic stress and longer exposure to mechanical stress, both of which can create a stimulus to new muscle growth,” Somerset says, “especially if that stress is somewhat new for the individual or greater than the amount of stress they’re used to.”
Metabolic stress occurs when substances left over from ATP (energy) production build up in your muscles. These chemical byproducts include lactate, hydrogen, phosphate, and creatine. Meanwhile, mechanical stress or tension refers to the force placed on the muscles during resistance training.
Thus, by increasing metabolic stress and/or mechanical tension, you force your body to adapt to the higher demands that you place on it, leading to more potential muscle growth.
However, no TUT workout can inflate your muscles without the raw materials supplied through proper nutrition, specifically protein and carbohydrates. These macronutrients provide the building blocks needed to promote muscle repair, recovery, and growth.
Benefits of Time Under Tension Training
Tempo training is typically associated with hypertrophy — and for good reason: It works. But TUT offers additional benefits.
Builds muscular endurance
The metabolic stress created by TUT can be beneficial for building muscular endurance. The National Association of Sports Medicine (NASM) defines muscular endurance as the muscle’s ability to create and maintain force production for an extended period.
To sustain a given workload for a greater duration, your muscles must get rid of metabolic byproducts before they can build up and make you fatigued — and TUT can help with that.
“A longer TUT makes the muscle work for longer periods, which means being efficient at managing the use of fuel and removal of waste products,” Somerset explains.
Boosts mind-muscle connection
Be honest: Do you mindlessly pump out sets during your strength workouts? Or do you focus on contracting specific muscles and fighting the negative in each rep?
The latter is known as a mind-muscle connection, an effective means for increasing muscle size, research finds.
TUT can help you achieve greater mind-muscle connection because it forces you to stay focused during the longer reps, Somerset says. In other words, you can’t rush through the movement.
Improves strength
Time under tension training often emphasizes slowing the eccentric or lowering phase of an exercise (like lowering into a squat). Research shows that this is the phase where your muscles are strongest and produce the most force.
By increasing the time spent in the strongest phase of an exercise, your muscles will adapt to generate more force. The result: greater strength.
How to Use Time Under Tension in Your Workouts
Now that you know what TUT is and the benefits it offers, here’s how to put the theory to practice.
1. Limit how much TUT you do in a single workout
When done right — with a challenging load, pace, and rep count — tempo training creates a good deal of muscle damage, so expect to feel sore the day after your workout.
Sports performance coach James Shapiro, CPT advises erring on the side of caution. “If you want to be able to use any of your limbs or walk the next day, I recommend doing only one or two exercises with TUT.”
You can gradually increase your TUT as your body gets used to the new stimulus.
2. Use a lighter load
Once you slow your pace, you probably won’t be able to lift your typical weight for a given rep count. Be prepared to lighten your load with TUT.
“When selecting a load for TUT, I recommend using 60 to 65 percent of the maximum you typically use if performing larger, compound movements like squats, lunges, bench presses, or rows,” Shapiro says.
For single-joint exercises, like bicep curls, triceps extensions, or leg extensions, Shapiro recommends going 10 to 20 pounds lighter than your usual weight and performing five to eight repetitions.
3. Use the 2-0-1-0 tempo
There are endless tempo varieties to choose from. However, it’s best to start simple.
Begin with the 2-0-1-0 tempo, suggests Vanessa Mandell, CPT. Spend 2 seconds on the eccentric (lowering) phase, 0 seconds at the mid-point of the exercise, 1 second on the concentric (lifting) phase, and 0 seconds at the end of the exercise.
“A lot of beginners rush through the movements, but incorporating a basic tempo like [the 2-0-1-0] will help them control the weight and get more out of each rep,” Mandell says.
4. Try the 40-30-5 method
Once you’ve gotten the hang of tempo training, feel free to experiment with more challenging variations, such as the 40-30-5 method.
The 40-30-5 method involves working for 40 seconds, resting for 30 seconds, and repeating until you’ve completed five rounds. The weight you pick should feel challenging toward the end of the 40-second work interval.
However, Mandell notes that it may be tough for beginners and even intermediate lifters to keep up with the same weight for all five rounds, “considering the rest is so short.”
Lengthen the rest interval to 40 to 45 seconds if needed, so you can focus on performing well during the work period. “With time, you’ll be able to work your way down to 30 seconds of rest and feel the pump from this efficient method,” Mandell says.