Hi Paul ... thanks for asking about this in the forum. Firstly, as you know, I am not a doctor so you really want to be sure that whatever you do, you check with the professional already helping you out. Having said that, sometime the health care profession only looks at muscular exercises to help out this condition, which is good, but I believe they could do more.
Plantar Fasciitis can have many causes: the online American Family Physician (
http://www.aafp.org/afp/20010201/467.html) has several causes listed, but definitely running too far, too often can be one of them. They cite "The pain is usually caused by collagen degeneration...The cause of the degeneration is repetitive microtears of the plantar fascia that overcome the body's ability to repair itself. " Well, collagen strengthening is a big part of Yin Yoga.
Many of their suggested actions are great (see
http://www.aafp.org/afp/20010201/477ph.html for several suggestions), and they all revolve around strengthening the area; you can use several Yin Yoga poses to help too.
I would try these postures (to learn more about them, check out their descriptions in YinSights...just visit the tab to the left and you will find them in the detailed table of contents):
Toe stretch - hold for two minutes, then go to
Ankle stretch - hold for one minute, then repeat both of these one more time
These should help activate strengthening in the fascia of the feet. Also try
Squat - fold for two minutes (if the knees are ok) then go into
Dangling - for two more minutes, then repeat both once more
Overstepping Dragon - for two or three minutes followed by
Dragon splits - for one or two minutes
These postures will not affect the feet so much as the ankles and calves, but often it is tightness in these areas that lead to Plantar Fasciitis.
Paul, one other principle of Yin Yoga applies here: Yin is not restorative yoga...when the tissues are already damaged, it is not a good idea to stress them again. Let them heal, and then rebuild them slowly. So, I would not suggest you do any of the above postures until you have no pain at all when you try them.
Good luck, let us know how it goes or if you come across other suggestions that work for you.
cheers
Bernie