The 12 poses in the yoga practice for this study were each held for 30 seconds and included the following: tree, triangle, warrior II, side-angle, twisted triangle, locust, bridge, supine hand-to-foot I, supine hand-to-foot II, straight-legged twist, bent-knee twist and corpse pose. They are pictured in this article in the Harvard women's Health Watch and below is a link to a video with Dr. Fishman, the researcher, narrating.
Some articles (Livestrong) have warned that certain yoga poses can increase fracture risk by flexing the spine. The general rule of thumb is to hinge at the hips and keep your back straight, bending the knees if needed, rather than curving the spine.
Poses that involve gentle twisting of the spine do not seem to cause fractures, in fact, Dr. Fishman, the author of the 10-year study mentioned above, recommends gentle twisting as a way to strengthen the spine.
Practicing these 12 poses is something you can do at home, with minimal props. And a 12-minute routine seems possible, even if you are busy. I'm planning to try it, in addition to my once-a-week yoga class. What a great way to start or end the day!