Thigh Flexion and Extension

Flexion of the thigh is also called flexion of the hip.

Muscles: iliopsoas (psoas major and iliacus) is the most powerful flexor, assisted by sartorius, rectus femoris, and pectineus.

Extension of the thigh is also called hip extension. Any movement away from flexion is extension.

Muscles: gluteus maximus is the most powerful hip extensor, assisted by the hamstring muscles (semitendinosus, semimembranosus, biceps femoris).