Standing forward folds are done all the time in yoga. Also known as uttanasana or even the rag doll, you simply hinge from the hips, hang, and let everything relax. For most people, it feels wonderful. As mentioned in my book, "From the Boxing Ring to the Ashram," this is a great way to decompress the spine and release any physical or emotional tensions from your body.
The standing forward fold is one of the easiest of inversions to stimulate blood flow and circulation. Plus, it lengthens all the muscles on the back of your body from the Achilles tendon to your neck.
However, any forward folds, with a rounded back, are contraindicated for people with low bone density or sciatica. Furthermore, people with uncontrolled high blood pressure should never let the head hang below the heart. On the other hand, anyone with low blood pressure should never come to standing from the full uttanasana without first resting in ardha (half) uttanasana (pictured here). Traditionally in ardha uttanasana the hands hang or rest on the shins. The variation in the photo helps ensure your back is straight, as it's very common for people to incorrectly hang the head or have a rounded back in this pose.
That's why I often recommend ardha uttanasana. In fact, I feel a greater stretch and lengthening throughout my spine, and hamstrings, when I practice this pose.
For more do's and don'ts for people with osteoporosis or osteopenia, view my YouTube video tutorial.