Osteoporosis means bones with microscopic holes in them. The total weight of the skeleton is therefore reduced. The bone that is left is normal, but there is much less of it. Bone lives and remodels or sculpts itself throughout life. Calcium and phosphorous turn over daily in our boney calcium bank.
Bone is piezo electric, which in Greek, means pressure produces an electric current.
The current, in turn, stimulates the formation of bone. I remember an elderly lady, Mary, in her 85th year who was walking or even shuffling when she fell on her rump and fractured her hip. About ten years earlier she had developed a minor stoop and noted that she had lost an inch in height. She was petite and had a dowager's hump or minor hunchback. She had never drunk milk, she told me, as it made her gain weight.