Muscle contractions

There are 3 main types of muscle contraction, these are concentric, eccentric and isometric.

Concentric contractions occur when the muscle involved is shortened in order to overcome a resistance placed on it, for example, the biceps shorten when lifting a dumbbell in a bicep curl.

Eccentric contractions are the opposite, they occur when the muscle involved lengthens in order to lower an object or resistance placed upon it, for example, lowering the dumbbell at the end of a bicep curl causes the biceps to lengthen.

Isometric contractions occur when the length of the muscle remains constant and the resistance is not moved through space, for example, holding, without moving, an object.