Herbert doesn't recommend fast-paced or very athletic forms of yoga -- like Vinyasa or Ashtanga -- to people suffering from back pain. Instead, look for Hatha Yoga or Restorative Yoga classes, which should be slower and more tailored to people looking to unwind or relieve pain, tension, or sore muscles.
Sadie Nardini, a yoga instructor and blogger for Gaiam.com, recommends "Rodney Yee's Back Care Yoga DVD" or the "Mayo Clinic Wellness Solutions for Back Pain DVD" (both produced by Gaiam) as good places to start a practice at home. She says that poses like Standing Forward Bend, Downward Facing Dog, Pigeon, and Child's Pose are all good for people with back pain, although you should consult your doctor before starting any new practice. [Source: Nardini]
In the 2011 study, both the yoga and stretching classes focused on the torso and legs. The stretching classes consisted of 15 different exercises, including stretches for the hamstrings, hip flexors, and hip rotators, and each stretch was performed twice. Both the yoga and stretching classes were about an hour long, but the yoga classes also included breathing exercises and a deep relaxation period at the end.
While the researchers were surprised to see that stretching worked as well as yoga, they did admit that an hour-long class is actually a lot more like yoga than what most people consider "stretching" -- something that's usually done for five minutes before or after exercised, and not really focused on as a discipline in itself.
They concluded that either yoga or stretching -- in a therapeutic setting that's geared toward beginners -- can be good, safe options for people with moderate back pain. If you do attend class with a chronic pain or injury, be sure to tell your instructor about it beforehand, so he or she can suggest modifications for poses that might be uncomfortable, or even dangerous, for you.