When exercising, or possibly even while rehabbing an injury, you may have heard the terms concentric and eccentric muscle contractions.

What do these terms mean?

Does it matter if you know the difference between the two?

Learning these terms and the difference between them can actually be very helpful when it comes to making sure you’re getting the most out of your exercise routine. Certain muscle contractions are considered more beneficial than others to practice, depending on the goal of the exercise and workout routine you’re performing.

We’re going to define these terms more clearly and explain how you can utilize them while exercising to get the most out of your home routine.

Let’s get started!

Defining Concentric and Eccentric

We’ll start off by defining the terms concentric and eccentric.

A concentric muscle contraction involves the working muscle shortening during the contraction. When the muscle shortens, the force created through this is transferred to the attaching tendon, then to the bony region the tendon connects to. This causes our joints and limbs to move (1).

An example of a concentric muscle contraction is a bicep curl. When you bend the elbow and curl the arm, bringing the forearm and hand closer to you, you are practicing a concentric contraction.

In contrast, an eccentric muscle contraction involves the working muscle lengthening during the contraction. This lengthening occurs because an outside force placed on the muscle is surpassing the force produced by the muscle itself (2).

Let’s refer to the bicep curl again. Once the arm has performed the curl, it must lower back down to its starting position. The arm should be able to perform this descending motion in a smooth, slow and controlled manner. The lowering of the arm back down from the bicep curl itself is an eccentric muscle contraction.

So, that’s how you differentiate between a concentric and eccentric muscle contraction!

Now, let’s do a little more in-depth side-by-side comparison of each contraction.

Comparing Concentric and Eccentric Muscle Contractions

Now that we have a basic understanding of what concentric and eccentric muscle contractions are, what do we do with this information?

The purpose of knowing the difference between each type of muscle contraction is to be able to make an informed decision as to which contraction/s you should be including in your exercise routine. Which one you focus on depends on a few factors, such as your age, fitness level, overall health, and goal of your workout.

Studies have shown that eccentric contractions are able to produce greater forces, but at a lower metabolic cost (2). This means that you may not fatigue as easily with eccentric versus concentric muscle contractions. As a result, eccentric muscle contractions are more encouraged among older populations, for a more tolerable exercise routine (1).

The downside to this though, is that it seems eccentric exercises have a greater potential to create greater muscle damage (2). This doesn’t mean you have permanently damaged or injured your muscles. Exercise-induced muscle damage can commonly occur after exercising to the point that you may have over-exerted the muscles or introduced them to something they are not used to, especially if practicing a new exercise or whole new routine. This can cause delayed-onset muscle soreness (DOMS), which can create excessive muscles soreness and pain over the next 24-48 hours post-workout. The muscles will recover from this, but this type of muscle damage is more common in eccentrics versus concentric muscle contractions, so this is something to consider (2).

It’s possible to combat and reduce the intensity of exercise-induced muscle damage, so that you can incorporate all recommended and important muscle contractions. Post-workout recovery can be helpful with inclusion of appropriate rest, stretching, icing, etc. It’s also helpful to remember that as you practice a particular muscle contraction over a period of time, with the appropriate amount of rest for recovery in between workout sessions, your body will accommodate and adapt, meaning reduced occurrence of exercise-induced muscle damage (2).

There is a bit of a discrepancy in determining if one type of contraction increases muscle mass more than the other. Traditionally, concentric contractions have always been known to increase the size of muscle, otherwise known as muscle hypertrophy. It’s important to note though that studies have been showing mixed results in this area. Some say that concentric will create greater muscle mass and hypertrophy, while others are more in favor of eccentric muscle contractions for this purpose (1).

Key Takeaways

As you can see, there are different pros and cons between concentric and eccentric muscle contractions.

Which you choose to practice, as mentioned above, depends on your individual health, where you’re starting in your workout journey, goals of your workouts, and if you have any injuries you need to be mindful of, just to name a few.

Because of some of the mixed results between the concentric and eccentric muscle contractions, there is something to be said about mixing in both types of contractions to your routine (1).

There is a potential benefit to this, in order to maximize the results to your muscles, but keep in mind that your whole workout routine should not necessarily be a combination of concentric and eccentric contractions within each exercise. Generally speaking, try to switch things up. You can include isolated concentric and eccentric exercises, as well as a combination of both. This may help to give you the best results and avoid your body getting used to the same old thing, therefore, allowing you to keep producing positive results when you exercise.

If you are recently recovering from an injury or surgery, make sure to always discuss your home routine with your doctor, surgeon, and/or therapist, in order to avoid practicing something that may set you back with progress.

Resources:

1.   Franchi MV, Reeves ND, Narici MV. Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations. Frontiers in Physiology. 2017;8(447). doi:https://doi.org/10.3389/fphys.2017.00447.

2.   Hody S, Croisier JL, Bury T, Rogister B, Leprince P. Eccentric Muscle Contractions: Risks and Benefits. Frontiers in physiology. 2019;10(10):536. doi:https://doi.org/10.3389/fphys.2019.00536.