types of muscle contraction and why they matter

Three Types Of Muscle Contractions – And Why They Matter

Time for our Workout Of The Month. Each month we take a look at a different exercise and break it down by movement, how to do it, and discuss some of the positive versus negative impact that it can have to you and your level of fitness. Some workout’s of the month breakdown how to do a common exercise, others feature a specific workout. This month we’ll taking a look at a little fitness 101: understanding the three types of muscle contraction: concentric, eccentric, and isometric – and why muscle contraction matters.

Types Of Muscle Contraction

Concentric Muscle Contraction

Concentric muscle contraction is when a muscle fiber is shortened to generate force to move an object. For example, a bicep curl: during a bicep curl, the muscle is contracting, or shortening, to generate force to bring a weighted object closer up to your shoulder. The same with a bench press – during the bench press the pectoralis muscles are contracting to lift the weight upward from your body (1).

Eccentric Muscle Contraction

Eccentric muscle contraction is the opposite of what concentric contraction is. For eccentric muscle contraction, the muscle is lengthening. Let’s use the biceps curl exercise again. After the biceps have fully contracted and lifted the weight up to your shoulders, the lowering of the weight back down to your side would cause the muscle to lengthen. This would be eccentric muscle contraction. For the bench press, lowering the bar would cause your pectoralis muscles to be lengthening (1).

Isometric Muscle Contraction

Isometric muscle contraction is when a muscle is activated, but instead of being allowed to lengthen or shorten, it is held at one constant length. An example of this would be holding a plank position or pushing your body against a wall. An isometric muscle contraction could also be doing a barbell curl and holding the weight halfway through the curl and stopping to hold the weight in place.

The strength of an isometric muscle contraction is depends on the length of the muscle during contraction – muscles have an optimal length/tension ratio for producing force.

The Importance Of The Three Types Of Muscle Contraction

Sometimes it’s kind of hard to understand the importance of the three different types of muscle contraction when it comes to traditional weight lifting. However, the types of muscle contraction is something that is happening all the time whether we realize it or not . For example, during a push up, the muscle of the neck work isometrically to help stabilize the neck from lowering towards the floor. The same goes for during squats when the muscles of your legs work isometrically to keep your knees from swinging too far in or out. You can strengthen muscles isometrically by holding a fixed weight in a fixed position for a fixed amount of time. Such as planks. Or holding holding a squat position.

Every day functional activities are the easiest to understand concentric muscle contractions, especially sports. Let’s say that someone plays football or soccer. When a person is pushed into you, the muscles of the body work to slow the force of the person being pushed into and absorb the force. To easier visualize it, you could imagine performing a bench press: if you load the bar with too much weight the muscles wont be able to work against the resistance of the weight and it will fall on to your chest. Eccentric muscle contraction works to slow the bar as it lowers to your chest.

In the fitness world, eccentric contraction is known as a “negative.” To work on strengthening the “negative” or eccentric contraction, you can simply slow the amount of time it takes for the eccentric contraction. For example, instead of taking two seconds to lower a bar to your chest during a bench press, take four seconds. Or, during a biceps curl, take four seconds instead of two to lower the dumbbell back down to your hips. The slowing of the time puts more exertion on the muscle and will build strength.

Putting The Three Types Of Muscle Contraction Into Perspective

Training is all about creating a good balance of strength between all types of muscle contraction. In the every day world of muscle movement, it’s usually our weakest link that eventually leads to some type of muscular injury. While being able to produce force through concentric muscle movement, it’s also important to take time to train and strengthen other types of muscle contractions. Your body will thank you.

Sources:

1. N.a. “Types Of Muscle Contractions.” Muscle Physiology. University of California San Diego. 31 May 2006. Web. 20 June 2015.
2. Clark, M., Corn, R., Lucett, S. “Muscle Actions.” NASM Essentials Of Personal Training. National Academy Of Sports Medicine. Baltimore: Lippincott Williams & Wilkins. 2008. Print. 62-68.

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