MUSCLE PHYSIOLOGY

Detailed explanation-1: -Gluteus maximus is an antagonist of iliopsoas, which does hip flexion, because gluteus maximus, which does extension of the hip, resists or opposes hip flexion.

Detailed explanation-2: -The gluteus maximus works with the semitendinosus and semimembranosus muscles to extend the hip. The muscle also works in conjunction with the iliopsoas, piriformis, and obturator muscles to externally rotate the hip.

Detailed explanation-3: -Agonists: Gluteus Minimus, Gluteus Maximus, Gluteus Medius, TFL. Antagonists: Adductor group-Pectineus, Adductor Brevis, Adductor Longus, Gracilis, Adductor Magnus.

Detailed explanation-4: -The hamstrings are agonists during both hip flexion and extension, but the most important antagonists are the psoas and iliacus muscles. This makes complete sense, as these muscles contract to bring the hip joint forward, and should, therefore, relax during the opposite movement.