concentrics and eccentrics defined

Have you ever thought about what the terms "eccentric" and "concentric" mean when it comes to exercise?

This article is inspired by a number of questions we get during courses about the properties of concentrics vs eccentrics and what the actual differences are between them.  It can be helpful to understand these definitions to improve our communication with clients, as well as helping us with modifying exercises for individual body structures.

​So what is a concentric?

The concentric is the portion of the movement/exercise that requires you to "overcome" the resistance.  This is where the muscle is "shortening" under load. For example lifting a dumbbell in a bicep curl.

What is an eccentric?

The portion of the exercise where you are no longer "overcoming" the resistance.  It is essentially a "lengthening" contraction, whereby the muscle is still contracting, but with less tension than would be required to move the load concentrically.  For example: Lowering a bicep curl.

Ultimately, an eccentric will likely be less demanding as you are not required to "overcome" the resistance in an eccentric.  Assuming you are using the same weight, a concentric it will take more "output" from the muscles in order to overcome the resistance and create movement. 

Why can I move more load through an eccentric?
You will generally be able to move more load in an eccentric due to the fact that you are no longer required to overcome the resistance. 

​Is it useful then to increase load for the eccentric portion of the exercise? 
It could well be, that will depend on your client, their individual body structure, goals and tolerance levels.  Just note that when doing this, you will be increasing the overall volume of that workout.

​Will I get less DOMS if I only do concentric reps?
It's highly possible, since you are ultimately reducing the amount of volume you are doing in that specific workout.

We hope you found the above information helpful.  ​If you have any questions on this or would like clarification, please send us an email or get in touch on our facebook or instagram pages and we'd be happy to discuss.

Source: The resistance training specialist program 2019.