This video shows a hip exercise to strengthen external rotation of the hip.
If you are unable to view the video, here is a still sequence of the exercise -
|Lie on your side on a firm surface with the head supported.|
|Keeping your feet touching, widen the space between your knees.|
|Hold the top leg in that position a few seconds.|
|Lower the knee to close the gap again.|
|Relax and then repeat the sequence 10 times.|