AFAA Personal Trainer Certification Practice Exam

Which type of muscle is referred to as the agonist?

1. The muscle that opposes movement

2. The muscle that contracts to create movement

3. The muscle that relaxes during contraction

4. The muscle that maintains posture

The correct answer is: The muscle that contracts to create movement

The agonist muscle is the muscle primarily responsible for initiating and controlling a movement during an exercise. When a muscle contracts to create movement, it generates force that enables the desired action – for example, when performing a bicep curl, the bicep acts as the agonist as it shortens and pulls the forearm upward toward the shoulder. This relationship is crucial in understanding how muscles work in pairs during movement, where one muscle (the agonist) is actively engaged, while its counterpart, the antagonist, works to modulate the movement. Recognizing the role of the agonist helps in designing effective workout programs and understanding the biomechanics of exercises.