Hi Sarah. I’ve worked with several women with osteoporosis or osteopenia. I totally agree with Steve that the first step should be to discuss this with your client’s treating physician (with her permission of course). Working with and through her physician is essential when working with this condition. My client presented with osteopenia and after several months of our working together, had a completely ‘normal’ bone scan on her next doctor’s visit. It can be done as long as it’s done safely!
Rowing is a fairly low-impact exercise, but again, I’d check with her physician to make sure that this is not contraindicated for her. You don’t mention what part of your client’s body is affected by the osteopenia, so that also will have an impact on what exercise is appropriate for her.
i hope that this helps.