Muscle agonist-antagonist


Interaction of the muscles

There are around 650 muscles in the human body. These fulfill different tasks. Part of it is responsible for the movements we make with arms, legs and other parts of the body. The muscles in our extremities are important for this. Another part takes on the support function and ensures that we do not collapse. This function is mainly performed by the core muscles, i.e. abdominal muscles and back muscles.

In order to be able to perform these functions, many muscles need to work together.A single muscle is often not responsible for a certain movement, but several muscles together.

The interplay of several muscles enables, on the one hand, a greater development of force with the same function of the active muscles and, on the other hand, a finer force adjustment when exercising force in two different directions.


The word Agonist means "the doer". In medicine or in anatomy, the muscle is called an agonist, the one performs a specific functionwho therefore acts. He is also known colloquially as a "player".


When a movement is made, it must always actively tensing a muscle become.

Also, with every movement there is a muscle that is the result of the movement passively stretched becomes. He is called antagonist or referred to as an opponent.

As the agonist moves, the antagonist is stretched. Often times the antagonist is the reason one move only to a certain extent can be performed, such as stretching the leg backwards. Here, among other things, the hip flexors prevent further extension.

The antagonist also has the function of corresponding countermovement to execute.


Suppose we want to bend our arm at the crook of the elbow. In this case it is Biceps as the executive muscle of the Agonist. It is the muscle whose contraction causes the arm to flex.

In the course of this movement, the on the other side of the arm becomes the Triceps stretched. The triceps also have the task of the arm to stretch againif we want that.

In the Stretching movement the terms then turn around. Then it is Triceps the executive muscle, so the agonist, and the Biceps are passively stretched and acts as the antagonist of the Countermovement (in this case the flexion) can perform.


The muscle that the same function performs like the agonist. Often there is several synergiststhat all work together.

For example, when you flex your arm, there are other muscles in addition to the biceps that can trigger a flexion. The Teamwork all of these muscles ultimately lead to the final movement in its total extent.