It's natural to think about bone strength as the whole story. Bone density is what makes a bone fragile — but a fragile bone doesn't break on its own. It breaks because something happened to it. For most fragility fractures, that something is a fall.
That distinction matters, because it means fracture prevention has two sides. One is bone strength — which you measure, monitor, and discuss with your physician. The other is not falling in the first place — which depends on muscle, balance, vision, medications, and your environment. And that side is largely in your hands.
Consider it this way: a person with moderate bone density and good strength and balance may fracture less often than someone with better density who falls twice a year. Both measurements matter. Only one of them is trainable.
Muscle is bone's protection. Strength and balance determine whether a stumble becomes a fall, and whether you catch yourself if it does. For fracture risk, that's as important as anything happening inside the bone itself.