Types of Muscle Contractions

Uncategorized on October 28th, 2010 No Comments

There are basically three distinct types of muscle contraction.

1) Isometric 2) Isotonic Concentric 3) Isotonic Eccentric

An isometric contraction is defined as a muscle contraction without joint movement. A good example of this is when a bodybuilder is posing for a contest and he holds the arm up to contract the arm muscles displaying the biceps brachii and triceps brachii.

An isotonic concentric contraction is defined as a muscle contraction with joint movement and is where the attachment sites are moving closer to each other. A good example of this is the classic biceps curl, the barbell, hand and forearm move closer to the shoulder. This is a concentric contraction of the  biceps brachii, brachialis and brachioradialis.

An isotonic eccentric contraction is defined as a muscle contraction with joint movement where  the attachment sites are moving farther away from each other. A good example of this is the down phase of a squat, the body is being lowered towards the ground as the knees and hips go into flexion. This is an eccentric contraction of the quadricep muscles, although the Rectus Femoris is a multi-joint muscle therefore the Rectus Femoris is probably not be changing length since the hip is flexing simultaneously.

In order to perform an isometric contraction you need to know the primary action of a muscle. Then you can provide resistance and this is a great way to help isolate and outline the distinct location and borders of muscles, assisting in accurate palpation technique.

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