With your client lying prone, have them lift their knee toward the ceiling. Place your knee under your clients knee, then have them press their knee downwards with 10% of their strength for 10 seconds. Then have them lift their knee, and you assist them at the end of the stretch. You can repeat this several times.
If your client is straightening their knee with either movement they are engaging their quadriceps. Have your client be relaxed at the knee so that all the movement or stretch is happening with the psoas and iliacus.
When they are pressing their knee downward they are engaging the psoas and iliacus. This will cause a post isometric relaxation allowing it to stretch further. When they raise their knee, they are using their glutes and hamstrings. This will cause a reciprocal inhibition of the psoas and iliacus, allowing them to stretch further.
This work is adapted from the Orthopedic Massage work of James Waslaski. More information may be found at www.orthomassage.net
This video is part of a series of techniques in a protocol for Pelvic Stabilization.