Our muscles are designed to do one job. They are designed to contract.

We contract our muscles when they need to generate tension against some sort of force. That force might be a grocery bag that we’re picking up from the floor. It may be a door we need to pull open. It could be a force we’re generating to push off the ground to run. 

When we think about muscle contractions, we might think of a muscle contracting to become smaller. While that is one way that muscles contract, there are other ways muscles contract to either become longer or maintain their length, depending on the movement we’re asking of them. 

When a muscle isn’t relaxing, it’s contracting, and it can contract in three different ways. The aim of this article is to simply explain the differences between the three types of muscle contraction, when they occur, and why we should care about them as people who want to move well and feel better.

Let’s get into it!

The 3 Types of Muscle Contractions

Concentric

A concentric muscle contraction occurs when the muscle length shortens. 

A standard biceps curl is a good example of this. The movement begins with the arm outstretched. The biceps contracts and its ends move closer together to bend the elbow and bring the hand toward the chest.

With concentric muscle contractions, the muscle is generating more force than the resistance--the biceps is generating more force than whatever dumbbell I’m holding in my hand. This is what bends the elbow to bring the hand up. If my biceps were in a competition to pick up the dumbbell, it would be winning so to speak. 

Eccentric

An eccentric muscle contraction occurs when the muscle ends lengthen away from each other during the contraction.

Let’s use the same example of the biceps curl here. When the biceps contracts concentrically to bend the elbow, the triceps (the muscle on the back of the arm) lengthens to allow that movement to happen. But the triceps isn’t relaxed during this time. Oh, no! It needs a considerable amount of tension to balance the force being generated by the biceps and to control the resistance of the dumbbell. During a biceps curl, my triceps is eccentrically contracting.

With eccentric muscle contractions, the muscle is generating less force than the resistance--the triceps is generating less force than the biceps, which allows my biceps to “win” the movement and bend the elbow to bring the hand up towards the chest.

Isometric

Isometric muscle contractions occur when the muscle ends stay the same distance from each other. 

Continuing with our biceps curl--let’s say we hold the position steady at the top for a few moments before releasing the hand back down and straightening the elbow. At the top of this position, the muscle ends are no longer shortening and lengthening, they are static. When our muscles need to work to hold a static position, this is an isometric muscle contraction.

FUN FACT: Isometric muscle contractions are considered analgesic, which means they have been found to stimulate pain relief. Think about this the next time your yoga teachers asks you to hold a pose for another 5 breaths!

With isometric muscle contractions, the muscle is generating as much force as the resistance, allowing the body position to remain stable. 

How They Fit Together

So far, we’ve talked through the muscle contractions involved in bending the elbow during a biceps curl. To review, during this stage of movement: 

• The biceps is concentrically contracting

• The triceps is eccentrically contracting

When we hold at the top of the position, all muscles are isometrically contracting. 

Now, what do you think happens when we straighten the elbow and bring the arm back down by the side? 

The triceps muscle is going to need to generate more force than the dumbbell which will move its ends closer together in a concentric muscle contraction. The biceps is going to need to generate less force than the triceps in order to let the triceps “win” the movement, which will lengthen its ends away from each other in an eccentric muscle contraction. When we hold the position at the bottom (which is actually a movement all by itself called the farmers walk--try it out, it’s one of my favs!), all muscles are isometrically contracting to hold the position.

Can you see how every movement we make involves some muscles concentrically contracting and other muscles eccentrically contracting? 

RELATED NOTE: In addition to concentric and eccentric referring to two types of muscle contraction, they can also refer to two phases of movement: Lowering down and lifting up. All movements that involve lifting and lowering can be broken into the eccentric phase (lowering down) and the concentric phase (lifting up). Lowering down from plank pose is considered the eccentric phase of the movement, whereas lifting up from the low push-up up into plank is considered the concentric phase. Squatting down to the floor = eccentric. Standing up from a squat = concentric. Lowering down from a pull-up bar = eccentric. Pulling your chin up over the pull-up bar = concentric. We are stronger in the eccentric phase of movements, so a good trick for progressing your strength is start building up your capacity to do the eccentric phase of the movement and then work your way towards mastering the concentric phase.

Why We Should Care

Our nervous system wants our body to be well-developed. This is when we feel the best physically and mentally. (And we are designed to feel really really good by the way, in case you’ve never encountered this line of thinking before!)

Now that we know that there are three different types of muscle contractions, we can extrapolate that a well-developed body means utilizing these three different types on a regular basis. When we prioritize a blend of concentric, eccentric and isometric contractions, we end up working our joints through a full range of motion, and we are supporting that range of motion in a balanced way on all sides of the joint.

There’s an adage that goes: You are only strong in the positions you train in. Training our biceps concentrically means we will get strong in our concentric range of motion. But training our biceps concentrically does not mean we will get strong in our eccentric and isometric ranges of motion. In order to get strong eccentrically and isometrically, we need to train eccentric and isometric contractions. Is the picture starting to come together for you?

Understanding this helps us develop a movement strategy that’s based on something other than wishful thinking. (And oh buddy, my yoga practice was based on wishful thinking for...8-ish years--I do not recommend this approach.) 

It’s really this simple: Our nervous system wants us to train our body concentrically, eccentrically and isometrically. Now the question becomes: How do we go about doing that?

Muscle Contractions & Yoga

In yoga, we do a lot of pose holding. That’s great! This helps us develop our muscles isometrically. 

In order to develop our muscles concentrically and eccentrically, our body needs to be moving through a range of motion. When in yoga class do we do this? I can think of a couple of examples: 

• Transitions (let’s say lowering down from plank to a low push-up position)

• Toggling between poses (let’s say flowing between a reverse warrior and an extended side angle)

• Pulsing in a pose (let’s say bouncing up and down in a chair pose)

These are all great opportunities to train our muscles concentrically and eccentrically. But here’s the kicker! We need to generate these movements with our strength rather than with momentum, leverage or gravity in order to actually experience the developmental benefits we’re looking for. 

In a fast-moving yoga class, I often times find myself relying on those passive ways of moving in order to move at the pace that’s being offered. It’s too much for my body to flow quickly through a sequence of end-range positions using only my strength, and so I often find that faster paced movement recruits less muscle contractions than slow, juicy movements. Food for thought when you step onto your mat next time. (The same way that when you watch people do biceps curls in a gym, they aren’t flying through the movement--they are articulating the movement slowly and recruiting muscle contractions to do it.)

This balance is always top of mind for me when I go in to teach a class (or when I record a class for my free yoga class library). But we are all ultimately responsible for creating this balance for ourselves. 

Next Steps

To begin assessing this, start by taking inventory of all the movements you do over the course of a week. 

• Are you moving your joints through a full range of motion in ways that are increasingly challenging? 

• Are there any gaps you can sense in the ways you’re currently moving? 

• How might you start to approach filling those gaps? (A big one for yoga lovers is a lack of shoulder pulling motions, so we need to find those elsewhere like climbing, swinging, swimming or utilizing a classic pull-up bar.)

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