Well I know that any impact training will help with bone developement. My mother is 58 and has the bone density of an 80 year old woman. My doctor did a dexa scan on me and said I actually have very strong bones. She attributes that to my marathon running. She basically said that when your running long distances and your bones are being constantly pounded on your body thinks your bones are under attack and that stimulates growth- or something along that line. But I'm not sure what moderate walking would do? I think I read somewhere that any impact training would help. The eliptical is not really an impact sport is it?
I guess I'm no real help here am I?? I'm tired... I think I need to go to bed! ha ha