Types of Muscle Contraction

Alex Smith

Isotonic muscle contractions, are those where the muscle changes length as it contracts. This type of contraction is responsible for the movement of body parts.

There are 2 types of Isotonic Contractions:◦ Concentric and◦ Eccentric.

Isotonic Muscle Contractions

Concentric muscle contractions are when the muscle shortens when it contracts.

E.g. bending the elbow, causing a concentric contraction of the Biceps Brachii muscle.

Concentric contractions are the most common type of muscle.

Concentric

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Eccentric muscle contractions occur when the muscle lengthens as it contracts.

This is generally used to decelerate an action by the muscle’s agonist.

Eccentric

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Isometric contractions occur when the muscle contracts but there is not change in the length of the muscle.

This occurs in situations like holding a weight stationary in front of one’s self.

Isometric Contractions

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The amount of force a muscle is able to produce during an is0ometric contraction depends on the length of the muscle at the when it contracts.

Each muscle has an optimum length at which the maximum isometric force can be produced.

Isokinetic contractions are similar to Isotonic muscle contractions in that the length of the muscle changes.

Where it differs however, is that the speed of the motion must remain constant.

An Isokinetic Dynamometer is used for this purpose.

Isokinetic contractions

To perform Isokinetic motions, generally a machine is used, to regulate the speed.

These machines apply resistance when the motion is too slow, or too fast.

http://allproexercise.com/client_images/catalog19894/pages/http://www.arielnet.com/adi2001/adi/products/aces/

http://www.lakeeriemed.com/lem-images/aerobic/

http://www.teachpe.com/anatomy/types_of_muscle_contractions.php

AS Level PE Book

Mac’s Notes.

Bibliography