To be honest, while this is fantasy story, the logic for becoming so strong by fighting bunch of sticks dangling on rope is just err....
A stick bounce back when hit, sure, but it don't actually tried to kill you, nor make you suffer, nor have experience of fighting. It has pattern, yes, but only one, you hit it, it flew away and then come back.
Human, animal, or you can say in this case, monster, fighting style are definitely not that predictable.