What You Should Know About Eccentric, Concentric, and Isometric Exercises
Are you a strength training regular, but feeling totally unmotivated after doing the same moves week after week? Or hitting a plateau and not seeing any new results? Your first instinct might be to add some ~fancy~ new exercises to your routine. While, sure, complex exercises can spice things up, you can actually work your muscles in a fresh way if you just pay attention to training an exercise in its various parts.
If you're scratching your head thinking, "Parts!?" keep reading.
Believe it or not, every strength-training exercise (whether bodyweight or heavy lifting) can be broken down into three main parts: the concentric portion, the eccentric portion, and the isometric portion of the movement.
"The concentric portion happens when the muscle contracts, the eccentric portion happens when the muscle lengthens, and the isometric portion happens when the muscle doesn't move at all," explains physical therapist Grayson Wickham, D.P.T., C.S.C.S., founder of Movement Vault, a digital movement education platform.
And while nine times out of 10, you're going to do an entire squat/deadlift/push-up, training each part of the movement separately does have its benefits. Below, learn more about the concentric vs. eccentric movements, what isometric exercises are, and the benefits of training them together or separately.
What Are Concentric Exercises?
The concentric portion of a movement occurs when the tension in the muscle increases and the muscle fibers shorten or contract, explains Wickham. The easiest example of a concentric movement is the bicep curl. Think about bringing the dumbbell from hip height up to your shoulder. "As the weight gets closer to your shoulder, the biceps muscle is shortening and the tension in the muscle increases," he explains.
Other common concentric movements include:
Lifting an object off the ground (or the first half of a deadlift)
Pressing to the top in a push-up
Standing up during a squat
Upward motion of a sit-up
The Benefits of Concentric Movement Training
"The concentric portion of a movement lends itself to increased power, speed, and strength," says Wickham. However, this portion doesn't strengthen the muscles as much as the eccentric portion of a lift does.
You'll get more on why below, but it's helpful to understand that in order for a muscle to get stronger, you actually need to damage the muscle. "You need to create microtears in the muscle that the body repairs and rebuilds even stronger than before," explains Wickham. Concentric movements don't damage the muscle as much eccentric movements do. While this means less strength gains per rep, it also means less delayed onset muscle soreness (aka DOMS), faster recovery, and less added muscle mass, he explains. (Related: Is Working Out When You're Sore a Bad Idea?)
There's not much benefit to training *just* the concentric portion of a movement, according to Wickham. But there are three times when you might want to focus on the concentric portion:
- Before a competition or race when you're worried about being sore. Let's say you have a CrossFit competition on Sunday. If your box programs deadlifts on Friday, you might keep soreness at bay by picking the weight up and then just dropping it, as opposed to lowering it back to the floor. (PSA: You'll need to use weight lifting pads, or make sure your gym has shock-absorbing floors to do this.)
- If you're a serious sprinter. Research suggests that the eccentric portion of an exercise is responsible for building more muscle mass than concentrics, so "sometimes advanced sprinters will just focus on just the concentric portion of movements like the deadlift to prevent from building thicker, bulkier muscles." The theory is that bulkier muscles will lead to slower sprint times. However, he's quick to note that for the general population of runners, this isn't necessary. "For most runners, the loss from skipping out on the eccentric portion of the lift is greater than the benefit of just doing the concentric," she says. Translation: not a good enough reason to opt out of the full lift. (Related: 5 Reasons Lifting Weights *Won't* Make You Bulky).
- If you're trying to dial-in form. It's common for coaches to have athletes focus on just the first half of a lift when they're learning how to do complex movements like a squat snatch or power clean. Usually, the goal here is just to safely nail the form, but technically, this is giving athletes practice with just the concentric portion of the lift.
The bottom line on concentric training: "Unless there's a specific reason you don't want to be sore the next day, it's best to train the concentric portion with the eccentric portion," says Wickham.
What Are Eccentric Exercises?
Also known as 'the negative,' the "eccentric movement involves lengthening the muscle fibers," says Ally McKinney, ACSM-certified personal trainer at Gold's Gym and GOLD'S AMP coach. Usually, this means returning the weight to start position. For instance, during the biceps curl, the eccentric movement happens while you're lowering the weight down to hip level.
Typically, "eccentric training" refers to training that emphasizes that portion of the movement. Think:
- Slowly bringing the barbell back down to the floor during a deadlift on a count of three
- Lowering yourself from a pull-up bar as slowly as possible
- Slowly rolling back during a Pilates roll-up
The Benefits of Eccentric Training
"Eccentric training places a greater demand on your muscles and central nervous system, so it's going to take you longer to recover from doing eccentric movements," says Wickham—but it's worth it. Remember: Eccentrics damage your muscle more than concentric movements do.
"There are so, so many benefits of eccentric training," says McKinney. In addition to strengthening your muscles, eccentric training helps strengthen your tendons and ligaments, which decreases your risk of injury, she says. In fact, one review found that eccentrics may help reduce the risk of muscle strain and tears, which is huge, considering women are more likely to tear their ACLs.
"Eccentric contractions can also literally make your muscle fibers grow, making the muscle itself physically longer," says McKinney. "Longer muscles means greater flexibility, and greater flexibility means greater injury prevention." (See more: Why Flexibility Is Important)
Wondering if you would benefit from eccentric training? "The better question is who wouldn't benefit," says McKinney .
What Are Isometric Exercises?
"During an isometric move, you're literally holding completely still at a particular angle so that there is no lengthening or shortening of the muscle," says McKinney. Not every exercise will include an isometric portion—but you can add an isometric portion to most by adding a pausing mid-movement.
Let's return once again to the biceps curl: Image curling your bicep to 90 degrees, so that your forearm is parallel to the floor, and then holding the weight there for ten seconds. That's isometric training. "Any movement that entails holding completely still might be considered an isometric hold," says Wickham.
That might look like sitting in the bottom of a squat, holding your weights with arms outstretched for 10 seconds during the arm moves in spin class, or holding chair pose in yoga. There are also some exercises that are isometric by nature. Think:
Hanging from the pull-up bar
Front rack kettlebell hold
The Benefits of Isometric Training
If you've ever done a wall sit or sat in the bottom of a squat, you won't be surprised to hear that even though you're not actually moving, "Isometrics still force you to engage your muscles, and therefore can help make you stronger," says McKinney. Because holding still requires you to really engage your core, isometrics can be used to increase balance and body control, too, she adds.
Isometrics can also help you break through a strength plateau. You're weakest in your end ranges of motion, explains Wickham. Think about a heavy back squat for example: pushing the weight up from the very bottom, or the "hole" is typically where most folks struggle. But sitting in the bottom of your squat with a weighted barbell on your back can help you develop the strength you need to stand the weight back up and hit a new PR, he says. The same concept applies to the push-ups or bench press, he says. Holding your body an inch or two above the ground during a push-up, will help make the entire movement easier. (Related: How to Work Towards a One Rep Max If You're New to Heavy Lifting).
"While you can't only do isometrics from now on and expect to get stronger, isometrics are great for anyone trying to break through a strength plateau or improve their mobility," says Wickham.
So Should You Train Each Portion of the Movement?
Yes! "If you use concentrics to build strength through the entire range of motion, eccentrics to build stronger and more resilient muscle tissue, and isometrics to increase strength at your end range of motion, you'll be a force to be reckoned with," says McKinney.
Still, you should only do this sometimes. You can't only train the parts, says Wickham. "You need to train the movement in full." Because as Aristotle once said, "The whole is greater than the sum of its parts."