I’d like to clarify some points about the Back Rx book mentioned a few entries ago. It should really not be considered a yoga book. The routines are closer to physical therapy than yoga. They are obviously designed for people who have had a serious back injury, have probably avoided physical activity for some time and need a lot of remedial work. Vijay Vad, the author, suggests four weeks on Series A before gradually switching over to the more demanding Series B. The criteria for graduating to the next level is to complete a full set without pain. I did the Series A exercises for a week and found them very easy. I then moved up to Series B for two weeks. This past weekend I switched to Series C, which is more Pilates in inspiration.
Vad says that each routine should take 15-20 minutes, but I found that prescription an underestimate, closer to 30-40 minutes, perhaps because I took longer, deeper breaths or I held the positions longer.
Again, the routines are focused exclusively on treating a back problem.