Antagonist (Biology)

In biology, an antagonist is a muscle that opposes the action of another muscle during movement. When one muscle contracts to produce a movement, its antagonist relaxes to allow that motion. For example, during arm bending at the elbow, the biceps contract, while the triceps act as the antagonist by relaxing or lengthening. This coordinated action helps control and smooth out movements. Antagonist muscles work in pairs to enable precise and balanced motions across joints.