Bone and muscle strength are built together. Weight bearing exercise is essential, because the bone responds to extra stress the weight imposes.
Plan to do lots of zone two exercise if you have the time. Brisk walking, dancing or tennis for example. Three hours a week minimum.
Three times a week do something really demanding, even just for five minutes. Like sprinting or walking quickly up a good slope.
This is worksheet three of eleven. Collect the set.