I think I'd better forget to practice my bones. Even if you can practice, like a Thai boxer, people practice since childhood, but they practice the hardness of bones. The rest I only know is that when a woman gives birth, her hipbone will be widened by opening her fingers when giving birth. Never heard of fitness and bone training. If you want to practice the muscles on both sides of the hipbone, there are still some ways. For example, you can lie on your side on the mat, straighten your legs together, slowly lift your thighs vertically, try to raise them as high as possible, and then slowly recover in a controlled way.