The Hip Roll

The hip roll is a very simple exercise which increases the range of motion in the hip joint. Supporting muscles are also strengthened.

Reduced (mainly internal or turning in) rotation of the hip joint is a fairly early sign of osteoarthritis in the hip. this can not only be painful but can also cause pain in other seemingly unrelated areas such as lower back and knees.
starting position

hip rotation start side view

Lay on your stomach with your hips parallel to the floor. Stomach should be tight. A cushion may be used under the hips if this is more comfortable.
Place your hands under your forehead.

hip rotation start rear view

Keeping the upper legs flat on the floor, bend one knee so that the leg is perpendicular to the floor (at 90 degrees).

Doing the exercise

hip rotation start of movement

Maintain the stomach and hip position. Take a deep breath in.
While exhaling slowly rotate your upper leg until your leg is pointing outwards at the extent of its movement range.
Hold this position while taking another deep breath in.
While exhaing slowly rotate your leg back in until the hip is at the end of its rotation in that direction.

hip rotation end of movement

Repeat this 5 times for each leg.

Ensure that your chin is tucked in.
Ensure your hips remain flat to so that it is the actual hip joint that is being moved rather than the lumbar spine.