The iliopsoas is a major muscle group in the hip region, consisting of two muscles: the iliacus and the psoas major. It plays a crucial role in hip flexion, allowing movements such as lifting the thigh towards the body. This muscle group is essential for activities like walking, running, and climbing stairs. The iliopsoas is also important for maintaining posture and stabilizing the spine. It connects the lower spine to the femur, helping to support the pelvis and lower back. Strengthening this muscle can improve overall mobility and reduce the risk of injury in the hip and lower back areas.