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Antagonistic Muscle n., plural: antagonistic muscle <ænˈtæɡənɪst ˈmʌsəl> Definition: a muscle the opposes the action of another


Definition that Antagonistic Muscle

What go the ax “antagonistic” mean? together the name suggests, words antagonistic method working opposite come the “agonist” or the “primary doer”. In biology, “antagonistic” describes an activity or substance that interferes or inhibits the physiological process. In anatomy, words antagonistic is provided to explain a muscle, an especially one that functions opposite come the action of the primary muscle. The muscle that functions in the opposite direction as that the the major muscle or agonist muscle, i beg your pardon is engaged in some activity.

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So i beg your pardon muscles room agonist and antagonist? The primary muscle that carries the end the activity is known as the agonist muscle or the primer muscle.How around the antagonistic muscles? What are they? In comparison to agonist muscles, the muscle that acts in the opposite direction to the of the agonist or the inside wall muscle is known as the antagonistic muscle. These antagonistic muscles also balance the stress and anxiety at the share by resisting the movement carried out through the agonist muscles. Permit us recognize the difference in between an antagonist muscle and an agonist muscle in Table 1.

Table 1: Agonistic vs Antagonistic muscles

Agonist muscles Antagonistic muscle
Agonist describes the doer of one action Antagonist refers to the opposition to action
As the name suggests, the agonist muscle is the doer or the major muscle carrying out the movement As the name suggests, the muscles the act the opposite or complementary to the major muscles
These muscles space accountable for the motion of the bones These muscles room responsible because that returning bones to their original position


Antagonistic Muscle (biology definition): a muscle the opposes the action of another. Because that example, as soon as the triceps oppose the convulsion of the flexing biceps through relaxing, the triceps would be concerned as the antagonistic muscle come the biceps whereas the biceps, the agonist muscle. Compare: agonist muscle.

Examples that agonist and also antagonist muscle pair are presented in Table 2.

Table 2: some of the Agonist and Antagonist muscles pair that outcomes in different varieties of movement

Agonist muscles and also their anatomical location Antagonist muscles and also their anatomical location linked movement
Muscle: Biceps brachii

Location: Anterior component of the arm

Muscle: Triceps brachii

Location: Posterior component of the arm

Flexing of the forearm by biceps brachii (Agonist)

Relax/lengthening through triceps brachii (Antagonist)

Muscle: Hamstrings

Location: Posterior component of the thigh

Muscle: Quadriceps femoris

Location: Anterior component of the thigh

Flexing the the foot by convulsion of the hamstrings (Agonist)

Lengthening that the quadriceps femoris to prolong the limb (Antagonist)

Muscle: mix of flexor digitorum superficialis and flexor digitorum profundus

Location: Anterior part of the forearm

Muscle: Extensor digitorum

Location: In the posterior part of the forearm

Flexing of the fingers and also hand in ~ the wrist is as result of the combination of the flexor digitorum superficialis and flexor digitorum profundus (Agonist)

Lengthening the the extensor digitorum to expand the fingers and the hand in ~ the wrist (Antagonist)


Muscle Contraction

What is a muscle action? Muscle action is the transformation in the bodily part that may an outcome in movement and it is because of a muscular contraction. Now, there are different varieties of contraction motions that can take place in the muscles. Contraction of muscle means the generation of anxiety in the muscle and also not necessarily the shortening that the muscles. Muscle convulsion can occur in the following ways:

Isometric contraction A kind of convulsion wherein no motion takes place, e.g., advertise or pulling any immobile object. In together a case, the tension produced by the contracting muscle is much less than the pack on the muscle. Isotonic contraction A form of convulsion wherein motion occurs, e.g., advertise or pulling any type of object successfully. Herein, the tension created by the contracting muscle is an ext than the load on the muscle. This contractions deserve to be more classified as:

Concentric contraction A type of isotonic contraction wherein the size of the muscle decreases against an opposing load, e.g., lifting a heavyweight in upward direction. Here, the muscle the decreases in length acts as an agonist muscle. Eccentric contraction A kind of isotonic contraction wherein the muscle increases in size while resisting a load, e.g., maintaining weight under in a slow and controlled way. The muscle that boosts in size serves as an agonist muscle and also carries out the work.
Muscle action (definition): the change in the body or in a bodily body organ or alteration due come the work of the muscle. Essentially, muscle contraction that outcomes in the movement of the details body part is known as a muscle action.

Read: Muscle Contraction mechanisms – biology Tutorials

Our human body is comprised of multiple levers that must coordinate in stimulate to bring out the body’s efficient movement. The duty of the muscles is come transmit the force to the skeleton via the tendons. As a result, the forced body part moves to bring out the plan action. This process is well-known as muscle contraction. Therefore basically, contraction that the muscle brings two bones closer to each other. This is additionally known as the flexing the the muscles that results in the movement of the bones. However, this convulsion of the muscle cannot place the two bones ago into their initial position, i.e., away from every other. Thus, another muscle team acts in the contrary direction to lug the bone back to its initial position. This team of muscles is recognized as antagonistic muscles. Thus, one team of muscle, i.e., inside wall or the agonist muscle contracts, permitting the activity of the bone; the antagonistic muscles, then, act in opposite or safety direction to take it the bone earlier to its initial position. Accordingly, to bring out any movement, the key muscle, or the agonist muscle, contracts and also shorten in length. Synergistically, antagonistic muscles work-related in security or the contrary direction, i.e., relaxes, to efficiently finish the activity of the primer muscle. Thus, when the agonist or the primer or agonist muscle contracts, the antagonistic muscle relaxes to complete the movement. In summary, the complementary activity of agonist and antagonist muscle is the prerequisite for any activity to be brought out efficiently.

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Figure 1: Antagonistic and agonist muscles: Biceps and triceps in different movements. (A) to raise the forearm, biceps (agonist muscle) contracts to raise the forearm, and also then the triceps (antagonistic muscle) relaxes; (B) To lower the forearm, the triceps (agonist muscle) contracts, and then the biceps (antagonistic muscle) relaxes. Source: Pinterest.

This more implies that the muscle functions in pairs wherein one muscle group takes up inside wall or agonist duties while the other features as one antagonist.

Some of the typically used terms to describe the complementary activities are:

Protraction vs retraction

For the reliable working the the muscles, fixators help by giving support and also stabilize the joint and also the remainder of the body. The fixators that help the agonist are recognized as a synergist, therefore when primer muscle contracts, the synergistic muscle simultaneously contracts. Synergists or synergistic muscle are additionally sometimes referred to as neutralizers as these muscles help reduce the extra movement induced through the agonist muscle, hence maintaining the working plane of the agonist muscles.

For example, for flexing the elbow joint utilizing biceps, the trapezius muscle acts together a fixator while stability the entirety body for the lower abdominal movement, i.e., hip and also knee movement, the abdominals act as fixators. The combination and coordination of four categories the the skeletal muscles, i.e., agonist, antagonist, synergist, and also fixator, bring out any movement in the body.

Take note that the antagonism that a muscle is no a fundamental or predetermined home of a muscle; the is a duty undertaken by the muscle complementary come the existing agonist muscle.

Let us understand this through an example.

Imagine a player who is around to take a kick at a football ball. Before kicking the ball, the knee flexes. The hamstrings contract while the quadriceps be safe or lengthen in order to lug out the movement. In this example, the hamstrings take the agonist’s duty while the quadriceps serve the duty of the antagonist. See number 2.

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Figure 2: activity of muscle in a footballer in preparative phase to kick the football. Credit: Misty Benson (kicking a soccer round diagram).

Next, once the player has actually completed kicking the ball, the knee extends. This additionally results in quadriceps contracting while hamstrings relaxing. In this case, the quadriceps become the agonist when the hamstrings space the antagonist in this movement. See number 3.

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Figure 3: activity of the muscles during or after kicking the football ball. Credit: Misty Benson (kicking a soccer sphere diagram).

The role of Antagonistic Muscles

The antagonistic muscles offer two vital functions the the body:

Uphold the human body or body position, e.g., holding the eight out or standing erect regulating the hasty movement and keeping a check on the limb activity

Any activity in the body is the result of the coordination of activity between agonist and also antagonist muscles. The co-activation that these 2 sets of muscles is critical. Our expertise of the concept till now makes the clear that the co-activation that the antagonistic muscle provides resistance come the activity of the agonist muscle. In easier terms, this resistance is dubbed the stiffness of the joint. A details level of stiffness come the joint or the resistance to the motion is critically crucial to keeping joint stability under varying fill conditions. Thus, the activation of the antagonistic muscles is pertinent for transferring out any body movement.