I read a book called The Stark Reality of Stretching by Dr. Steven Stark that outlines safe ways to stretch. But it seems that many yoga postures are unsafe according to Dr. Stark and I now hesitate to teach them just in case. For example: is leaning forward in baddha konasana safe? I have been doing this for years and it feels really good when my lower back and sacrum ache. But DR Stark states that bending forward from the pelvis when the legs are abducted and externally rotated causes stress and tearing to the ligaments of the posterior pelvis. And it supposedly also weakens the ligaments of the lumbar spine. What are your thoughts?
I agree with him as far as hyper mobile students are concerned. For the average or tight students the motion is not a problem. The language of weakening ligaments is incorrect, as ligaments cannot contract. The motion can stretch the ligaments; as a result the joint is made unstable.