Smaller muscle groups with a similar functional ability might include the major which acts as synergist in producing the same action as the agonist.

Smaller muscle groups with a similar functional ability might include the antagonist major which acts as synergist in producing the same action as the agonist.

example : the biceps and triceps muscles of arm, work together as agonist and antagonist respectively.

The biceps helps to lift up or flexes the forearm and the triceps helps to extend it.

Explanation:

many muscles work together to make an action happen.

the muscle who is involved in an action principally, is known as prime mover or Agonist muscle.

Antagonist muscle does the opposite action  of the agonist muscle.

antagonist also helps in-

like, to move a bone , the muscles attached to it work together to make a movement happen. like- to lift up a arm, agonist or prime mover muscles helps to lift up or flex the arm and the antagonist or synergist muscle helps to extend it.

enzyme speed up the reactions