Hip Joints: scientifically referred to as the acetabulofemoral joint (art. coxae), is the joint between the femur and acetabulum of the pelvis and its primary function is to support the weight of the body in both static (e.g. standing) and dynamic (e.g. walking or running) postures. The hip joints are the most important part in retaining balance. The pelvic inclination angle, which is the single most important element of human body posture, is mostly adjusted at the hips.

Excerpt from: https://en.wikipedia.org/wiki/Hip