How do antagonistic muscle help in movement?
Role of the Antagonist The primary role of the antagonist is to move in contrast to the agonist. As the agonist shortens the antagonist lengthens and vice versa. When performing a bicep curl, the bicep is the agonist in the contraction and the tricep is the antagonist. As the elbow flexes, the bicep shortens as it flexes and the tricep simultaneously lengthens to allow the bicep to shorten.
Concentric Contractions During concentric contractions the agonist shortens against the load while the antagonist passively lengthens to accommodate the movement. However, a single muscle is not confined to the role of antagonist. For example, the tricep is the antagonist during a bicep curl, but the roles of the muscles are reversed when performing a tricep pressdown. Here the tricep is the agonist as it shortens with the concentric contraction and the bicep becomes the antagonist, lengthening to allow the tricep to shorten.
Eccentric Contractions Antagonists also play a role during certain eccentric contractions. Antagonists most often lengthen and shorten passively without actual activation of the muscle fibers. But when moving significant weight, the antagonist activates to control deceleration of the weight as the prime mover relaxes. The greater the velocity of the concentric contraction and the heavier the weight you’re moving, the more the antagonist activates to control deceleration during the eccentric return phase of the exercise. For example, if you’re moving a heavy weight during a bicep curl, your tricep will activate to help your bicep control the straightening of your arm at the end of each repetition.
Isometric Contractions Isometric contractions occur when muscles are activated but there is neither a shortening nor lengthening of either the agonist or antagonist. During isometric contractions, the agonist and antagonist contract simultaneously, which immobilizes the joint the muscles attach to. During an isometric contraction, both agonists and antagonists work as stabilizers to support the immobile joint.
The primary role of the antagonist is to move in contrast to the agonist. As the agonist shortens the antagonist lengthens and vice versa. When performing a bicep curl, the bicep is the agonist in the contraction and the tricep is the antagonist. As the elbow flexes, the bicep shortens as it flexes and the tricep simultaneously lengthens to allow the bicep to shorten.
Concentric ContractionsDuring concentric contractions the agonist shortens against the load while the antagonist passively lengthens to accommodate the movement. However, a single muscle is not confined to the role of antagonist. For example, the tricep is the antagonist during a bicep curl, but the roles of the muscles are reversed when performing a tricep pressdown. Here the tricep is the agonist as it shortens with the concentric contraction and the bicep becomes the antagonist, lengthening to allow the tricep to shorten.
Eccentric ContractionsAntagonists also play a role during certain eccentric contractions. Antagonists most often lengthen and shorten passively without actual activation of the muscle fibers. But when moving significant weight, the antagonist activates to control deceleration of the weight as the prime mover relaxes. The greater the velocity of the concentric contraction and the heavier the weight you’re moving, the more the antagonist activates to control deceleration during the eccentric return phase of the exercise. For example, if you’re moving a heavy weight during a bicep curl, your tricep will activate to help your bicep control the straightening of your arm at the end of each repetition.
Isometric ContractionsIsometric contractions occur when muscles are activated but there is neither a shortening nor lengthening of either the agonist or antagonist. During isometric contractions, the agonist and antagonist contract simultaneously, which immobilizes the joint the muscles attach to. During an isometric contraction, both agonists and antagonists work as stabilizers to support the immobile joint.
