What Is Eccentric Exercise—And Why Should You Practice It?

Going through the motions is never a good idea when it comes to fitness. Ask any trainer, and they'll tell you it's about quality, not quantity—and that phoning it in is more likely to hurt than help you.

Take a push-up, for example. You know lowering your body down then pushing it back up is considered one rep, but both of those steps—known as eccentric and concentric movements—are equally important. And when you understand and focus on those specific movements during exercise, it can help you vary your routine and up your gains.

Here's what you need to know about eccentric exercise specifically—and how to safely incorporate it into your exercise program to reach your goals.

What Is an Eccentric Contraction?

Whenever you put your muscles under tension, there are three types of contractions muscle fibers can perform: concentric, eccentric, and isometric, Teresa Guglielmo, CPT, a personal trainer based in San Diego and founder of FNL Health, told Health. A concentric contraction occurs when the muscles shorten, an eccentric contraction occurs when the muscles lengthen, and an isometric contraction occurs when the muscles stay the same length.

It's most helpful to imagine this through specific exercises, so picture a dumbbell bicep curl this time: When you flex or bend your elbow to pull the weight up toward your chest, that's a concentric contraction. And, when you extend or straighten your elbow to lower the weight back down, that's an eccentric contraction.

An isometric contraction would occur if you paused halfway and held the dumbbell at a 90-degree angle for a certain amount of time.

Eccentric contractions essentially act as a braking mechanism. "It's about controlling the lowering of weight while still maintaining tension through the muscle," Sergio Pedemonte, CSCS, owner of Your House Fitness, told Health. Think about it this way, said Guglielmo: When you're doing the eccentric part of an exercise, you're moving with the resistance—i.e. resisting the pull of gravity as you lower a weight—as opposed to moving against it.

Benefits

Eccentric training focuses on the lengthening phase of any particular exercise, which makes it killer for building strength. "By lowering the weight with control, you're able to create a great stimulus for growth even while the gravitational force of the weight is greater than the force the muscle is producing," explained Pedemonte.

Research published in 2014 in the Journal of Applied Physiology found eccentric training to be better at building muscle strength than concentric training. "You can lengthen muscles under loads much greater than possible to contract with," said Pedemonte. "It's a great tool for 'overloading' the body"—the key to making adaptations.

During an eccentric contraction, your muscle fibers get lengthened to a point that causes microscopic tears (think about pulling Velcro apart), which induces your muscle's inflammatory response; with proper recovery time, they'll repair and rebuild themselves stronger than they were before, Guglielmo explained.

"Eccentric contractions cause more muscle damage—in a good way!—than concentric contractions," added Guglielmo. "Because you're moving more slowly through the motion, overall force increases. Over time, your muscle will naturally develop increased strength to accommodate that increased force." Eccentric training also requires less oxygen, a lower cardiac output, and produces less lactate build-up within the muscle than concentric training when using similar loads, said Pedemonte—all of which is easier on your body.

It's not just about making gains, though. That lengthening of the muscle fibers can also improve flexibility and range of motion, said Guglielmo. Eccentric training was found to be an effective way to improve lower limb flexibility in a 2014 review of relevant scientific literature published in the British Journal of Sports Medicine.

The cherry on top: Strength training and improved flexibility both reduce the risk of injury. And eccentric training may also help build your body's connective tissue (think of it like a web throughout your body that supports and protects your muscles and organs), research published in 2016 in the Journal of Applied Physiology noted. So it's a triple whammy in terms of payoff.

Risks To Eccentric Exercise?

Any kind of training comes with its own risks. "Eccentric training is known for inducing DOMS, aka delayed onset muscle soreness," said Pedemonte. DOMS usually becomes apparent within 12 to 24 hours and subsides five to seven days after onset.

The effects of muscle damage from eccentric training will vary depending on the intensity of your workout. Remember, minimal micro-tearing of the muscles is a good thing: "That's what's been shown to create a stimulus for muscle growth," said Pedemonte. But when your muscles are recovering, they're weaker and more at risk for injury; that's why it's so important not to go all-out every day, and work in active recovery efforts like walking, swimming, or yoga.

Keep in mind, too, that because your body can handle more weight with eccentric exercise, you may be more prone to injuring yourself—think: strains (stretching or tearing a tendon) or sprains (stretching or tearing a ligament)—if you lift too heavy, too soon. "For example, if you try an eccentric pull-up, where you're slowly lowering your body away from the bar, but you're not able to hold your own body weight, you may drop too quickly and pull or tear something," said Guglielmo.

Make sure to slowly build up your strength to prevent injury. And don't be afraid to ask for a spotter, if needed. "Some exercises, like a bench press with a barbell, are safer when done with someone else," Guglielmo added. "It's always better to start 'easy' and increase the intensity if you're ready for it than to start too advanced and injure yourself."

How to Add Eccentric Training to Your Routine

Good news: Almost any exercise can be done with an eccentric focus, so you can start incorporating this type of training into any strength workout. "I'd recommend the basics to start: squats, deadlifts, push-ups, and rows," said Guglielmo.

Eccentric exercises are performed slowly, with control, to add to the muscle's time under tension. Try doing a three-second count on the lengthening phase of the exercise and a one-second count on the shortening phase, said Guglielmo.

In general, Guglielmo recommended doing eight to 10 reps per exercise and two to three sets. (FYI: You don't need to use weights. Eccentric exercises are an excellent way to increase the challenge of any exercise—just imagine a slow push-up from the floor.)

Because you may have more muscle soreness than you're used to (if you are new to eccentric training), give yourself 48 to 72 hours before repeating an eccentric workout. You want to make sure your muscles are fully recovered and repaired before taxing them again.

As for the big picture, stick to a three-week ramping-up protocol, says Pedemonte. Translation: "Slowly and incrementally increase the amount of weight and range of motion you use throughout the three weeks," Pedemonte explained. Then you can do a down or de-load week where you significantly lower the intensity, before picking back up where you left off. That recovery period is crucial, so you can come back stronger than you were before—and keep building toward your goals.