You must have the physical and mental strength to accomplish whatever you want in sport
You can see the sentence above, I want to say. I want to say some fact, and want to express some obligation, that it must-have for achieving something in sport, but as I see, construction must have used in different cases. According to this source we use it when we want to express believing that the action definitely happened. Can I use must have in my case, or it is used in the wrong way?