Bend knee to chest
The following are hip flexors.
The iliopsoas or inner hip muscles are made up of the psoas major, psoas minor, iliacus muscle. The anterior compartment of thigh muscles include the rectus femoris (part of the quadriceps muscle group), & sartorius. One of the gluteal muscles (tensor fasciae latae) & the muscles of the medial compartment of thigh (pectineus, adductor longus & brevis, & gracilis).