What is an antagonist muscle?

An antagonist muscle is defined as a muscle that opposes the action of another muscle, typically referred to as the agonist. When one muscle contracts to perform a movement, the antagonist works to relax and allow this movement to occur while also providing balance and control. For example, during a bicep curl, the biceps brachii is the agonist that contracts to lift the weight, while the triceps serve as the antagonist, relaxing to allow for the smooth motion at the elbow joint. This relationship between agonist and antagonist muscles is crucial for coordinated movements and maintaining joint stability. Understanding this concept is essential in exercise physiology, as it plays a significant role in designing effective workout programs and preventing injuries.