Which of the following is not an agonist/antagonist muscle pair?

The correct answer identifies the pair of muscles that does not represent an agonist/antagonist relationship. In this case, the gastrocnemius and soleus are not considered agonist and antagonist muscles because they primarily work synergistically. Both of these muscles are located in the calf and are responsible for plantar flexion of the ankle, which means they assist each other in performing the same movement.

Agonist/antagonist pairs consist of muscles that oppose each other in their actions. For example, the gluteus maximus and iliopsoas serve as an agonist/antagonist pair because the gluteus maximus extends the hip while the iliopsoas primarily flexes it. Similarly, the rectus abdominis and erector spinae are antagonistic because the rectus abdominis is a primary flexor of the spine, while the erector spinae extends it. In the case of the subscapularis and infraspinatus, they also demonstrate an agonist/antagonist relationship—subscapularis being a medial rotator of the shoulder and infraspinatus acting as a lateral rotator.

Understanding these relationships is crucial for designing effective training