Many people have been attracted to Yoga for its many benefits. 

Doctors have often recommended Yoga for their patients, to help with back pains, injuries to the limbs, or for routine post-operative care.

However, that does not mean Yoga is automatically safe for all.  It has come to light that many amateur enthusiasts force themselves into text-book (or video) positions even if the pose hurts.  The dangers are not just with the unsupervised beginners.  In class situations, there are instructors who will try to force all the people to get into all the poses, even if it means exhorting them past the point of pain or comfort.  Other instructors are too swift with their pacing, forcing participants to change positions too quickly for comfort. 

An interesting new look at Yoga has been written by William J. Broad, pointing out that many people should not be doing certain Yoga poses, and some should not be doing Yoga at all.  A compelling look at the good and bad sides of Yoga is to be seen in the following link, which is highly recommended: NYTimes-Yoga

However, this is an example of the universal rule of sports; not every body is suited for every activity.  That’s why such diverse body types excel in the Olympics, where the marathoners and sprinters have completely different strengths and aptitudes, not to mention body builds.  And, within running, there are many of us who are simply not built for it, such as people with issues of bony alignment, arthritis, or pains when running on concrete.  Others are not suited to the mental discipline required in long distance running, and simply cannot appreciate the zen of it.  Swimming is another sport thought to be universal, but many just sink like a stone, or otherwise seize up with fear when they get near the water.

 So the point is to consider the whole menu of options for sports, activities, and therapies.  Following the latest fads is fine if you turn out to be well suited to it.  But be prepared to bail on even the gentlest of exercises if they don’t work for you.