An agonist muscle is a muscle that plays a part in the extension of a muscle. The agonist muscles for a knee extension are the quadriceps and hamstrings.
Antagonist: lats Agonist: Abdominals
Hip Extension the agonist would be Glutues Maximus
Flexor carpi
Agonist - Pectoralis Major, Triceps Brachii Antagonist - Bicep Brachii, Latissimus Dorsi
brain
medulla oblangata
prime mover (agonist)
Primer Mover (agonist)
extension of the spinal column , so yeah
Filium terminale
denticulate ligaments