At some point in your fitness journey, there’s a good chance you’ll max out the dumbbells, kettlebells, or weight plates you have access to at your neighborhood (or home) gym. The problem? You need these increasingly heavy tools to continue building strength and muscle.
At least, so you thought: Increasing your time under tension can help you progress your workouts without having to increase your load. So how does it work? Here, a fitness expert shares the benefits of upping your time under tension and how to make use of the resistance-training technique during your own workouts.
What Is Time Under Tension?
Simply put, time under tension refers to the amount of time your muscles spend contracting against an external resistance, says Tessia De Mattos, P.T., D.P.T., C.S.C.S., a physical therapist and strength and conditioning coach in New York. The slower you lower into and rise out of a squat, for example, the more time under tension, she says. “The total time that your muscles are contracting is much longer than if you were going at a regular pace,” she adds. You can increase time under tension by lengthening the concentric (when your muscle fibers shorten) or eccentric (when your muscle fibers lengthen) portions of a movement, says De Mattos. Or, you can get the job done by spending more time in an isometric position — holding still so there’s neither lengthening nor shortening of the muscle, research shows. (
The Benefits of Increasing Time Under Tension
Though increasing time under tension during your workout is pretty simple, it can be a valuable tool to use during your strength training routine.
May Increase Muscle Strength and Hypertrophy
By slowing down your reps and increasing your time under tension, you might see more muscle gains. In fact, a small 2012 study found that performing leg extensions with slow lifting movements until fatigue led to greater increases in muscle protein synthesis rates than when the same exercise was performed quickly. During muscle protein synthesis, cells rebuild damaged muscle with amino acids, which may ultimately encourage muscle hypertrophy (aka growth), says De Mattos. Similarly, research published in 2016 found that slowing down the eccentric portion of a movement increases muscle activation and production of blood lactate — a sign of fatigue within a working muscle, which itself promotes hypertrophy, according to information from UC Davis Health.
In theory, increasing time under tension, particularly during the eccentric portion of movements, should cause you to fatigue faster, she explains. There are a lot of good reasons as to why it should help improve your strength, but research hasn't caught up, says De Mattos.
Establishes Healthy Movement Patterns
Aside from potential gains, putting the breaks on your tempo can help you develop body awareness and learn the proper mechanics of a new movement, which can be particularly useful for fitness newbies, says De Mattos. “If a person has never worked out a day in their life or they don’t have any previous experience with being active, their body awareness probably isn’t great,” she adds. “[Increasing time under tension] is a great way to learn how to move.” Even intermediate gym-goers can learn a thing or two from slowing down their reps. If you’re intentionally performing a squat slowly, for instance, you may look in the mirror and catch your knees caving in or extending way past your toes — form mistakes that may go unnoticed if you constantly perform the rapid-fire reps, she explains. “It gives you the opportunity to correct that before you establish bad habits,” she adds.
Supports Tendon Health
While you can increase time under tension during concentric and eccentric movements, De Mattos suggests slowing down the latter portion, as doing so may help support tendon health. “There’s a lot of research that supports the fact that tendons, which connect the muscle to the bone, really like slow, eccentric loading — they respond really well to that,” she says. In fact, eccentric and heavy, slow resistance training have both been found to improve symptoms and tendon structure in people recovering from chronic tendon conditions.
How to Utilize Time Under Tension During Strength Workouts
Increasing time under tension is as simple as increasing the amount of time you spend performing each rep of a given exercise. But there are still a few tips you should keep in mind while incorporating it into your resistance-training sessions.
Use Bodyweight or Loaded Exercises
Since all exercises have eccentric and concentric phases, you can increase your time under tension performing any of your go-to movements, says De Mattos. You might slow down your squats, leg extensions, or Romanian deadlifts to strengthen your lower body or your bench presses and bent-over rows to do the same for your upper half, she adds. Or, you can increase time under tension by briefly holding your position mid-exercise, such as during a rep of the superman or Bulgarian split squat.
Plus, you don't need to use weights in order to feel the burn. "It's a great way to make [a bodyweight exercise] harder for yourself," says De Mattos. "Say you're just doing stuff at home and you don't have access to the gym — throwing in tempo, messing around with how fast or how slow you perform is a great way to introduce variation and progress yourself." If you are going to add weights, choose a load that's lighter than you'd use for regular reps, she suggests. "If you're increasing your time under tension and you're doing something weighted, it's going to feel a lot harder."
Count to Five
To perform an effective time-under-tension workout, you’ll want to spend about five seconds on each rep, says De Mattos. “Any more than that will feel like torture,” she jokes. If you want to push your limits, try aiming for six seconds per rep, which research has found to have the greatest effecton improving muscle strength, according to a review published in Sports Medicine. To make sure you actuallywork for that period, consider having a workout buddy count aloud (with Mississippis) or setting a timer, suggests De Mattos. Without this accountability, you might cheat your reps and only end up working for just half the amount of time needed to encourage muscle fatigue and hypertrophy, she says.
Don't Skip Rest Breaks
When increasing time under tension, giving your body a proper breather between sets is key. “If you’re doing something for strength or hypertrophy, you want to give your muscles adequate rest time — at least a minute in between sets,” says De Mattos. “If you’re going back faster than that, that means it wasn’t hard enough or you’re trying to get your heart rate up and it into a HIIT class, in which you’re improving cardiovascular health and endurance but not necessarily strength.” Translation: Just like your reps, don’t rush through your rest breaks.