If you've ever seen a bear stand up, its structure looks remarkably human.
Why? That's the easy part for anyone who actually can analyze shıt properly. Look at their feet. Look at the feet of other animals. Now look at human feet. We're two of the only mammals that are completely plantigrade. We both walk on the soles of our feet.
Looking at it scientifically and on an evolutionary scale, any unique skeletal qualities shared by 2 different animals will have to lead to more similarities between those 2 animals, since there are constraints placed upon the structure due to physics. It's the exact reason why deer and antelope are damn near identical structurally despite not being closely related. If a shape works, nature goes with it until it no longer does.
Since both humans and bears walk flat-footed, it only makes logical sense that both will have similar bone structures in bipedal form to accommodate the shared plantigrade trait.
Know your shıt. It's that easy.