A Pilates studio with a focus on osteoporosis is a good place to start your research, Therapilates based in Santa Cruz California is full of the stuff!
Flexion versus extension exercises are discussed in this research based article from therapilates.com.
On a more personal note, read how one Instructor manages her own Osteoporosis as outlined in this Pilates Pro article.
A home grown resource that is well worth a read is Osteoporosis Australia. Position papers, recently added information and an update on medications are all available.
