Concentric, Eccentric, and Isometric?

Every day the machine that is your body is put to work. It stretches, bends, and twists to aid you in even the most mundane of daily activities. With all those muscle actions, you might think people are putting their bodies to strenuous work.

So why aren’t more people in shape?

It turns out only 23% of Americans are getting enough exercise. 

But what if I told you that by understanding how your muscles work, you can optimize your workouts and create the healthy lifestyle you have always wanted? It’s really not that hard, and it starts with understanding the different types of muscle contractions. 

Here’s how they work.

Types of Muscle Contractions

When you exercise, your muscles undergo contractions. Contractions are when muscles are either shortened or lengthened. 

Muscle contractions can be either Isotonic or Isometric. During an isotonic contraction, the length of the muscle changes. Isotonic contractions are broken down further into either concentric or eccentric contractions, depending on how the length of the muscle changes. 

So in total, we have three types of muscle contractions: concentric, eccentric, and isometric. Now let’s talk about the differences between them.


During a concentric contraction, muscles shorten as they contract.

Picture yourself picking up a dumbbell, ready to begin performing a bicep curl. As you lift the weight up towards your shoulder, the biceps muscle shortens. This is a concentric contraction. 


During an eccentric muscle contraction, the muscle lengthens as it contracts. 

Picture yourself holding the same dumbbell in your hand. Your biceps muscle has already experienced a concentric contraction as you lifted the weight towards you. 

As you lower the weight to complete your curl your biceps muscle lengthens. This is an eccentric contraction.


Unlike eccentric or concentric contractions, isometric movement neither shortens nor lengthens muscle movements. There is little to no muscle movement. The angle of the joints remains unchanged during an isometric contraction. 

Let’s say during your biceps curl you stopped and held your arm still for several seconds, with the dumbbell still in your hand. This is an isometric exercise. Your biceps muscle remains static yet flexed. 

Even though they don’t shorten or lengthen the muscle, isometric exercises are beneficial. They’re easy to perform and activate many different muscle fibers simultaneously. 

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Why is Muscle Contraction Important

Muscle contraction is an important part of strength training, muscle growth, and rehabilitation. When we exercise, our muscles become damaged and need to be repaired. During this repair process, muscles grow. 

Different exercises will have different types of muscle contractions. Some exercises may be better suited for you, depending on your fitness goals. If you want to build lots of muscle, an compound exercises such as the bench press, squats, deadlifts, and overhead presses will help. However, if you are more endurance and stability oriented in your training, isometrics might be the path you choose to follow.

Just remember to stay safe, especially when weight training.

Let Us help You Out

At CONDITIONerd we are here to help you achieve better physical and mental health through exercise. Check out the plans we offer to our customers and see if you could benefit from working with our team. And if you have questions, you can always contact a CONDITIONerd team member

Personal trainers, like those found here, can help guide you on your pathway towards reaching your fitness goals, whether that is getting bigger, stronger, faster, more lean, or just generally feeling better.

We can get you setup with a periodized workout plan, supplement information, and advice on nutrition to help you reach your goals.

The only thing you need is some motivation and a willingness to change some old habits.

Get into contact with us to find out what membership is right for you. In a CONDITIONerd program, you’ll be surrounded by others who can help you to get where you want to be.

Generally, our clients start to see some pretty awesome changes in 2-3 months time, some sooner.

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