The iliacus is a key part of the larger and better-known hip flexor (the other main muscle being the psoas). Together, the iliacus and the psoas make up the hip muscle group that connects the ...

Hold this position, release, and then repeat on the other side. The iliopsoas comprises the joined iliacus and psoas muscles. These hip muscles are the main muscles that help the hip to flex.

You have to have a little patience," he continued. At the Australian Open in mid-January, Nadal injured the psoas iliacus in his left leg, and his recovery period was said to be between six and ...