Ohh ok I got it. strength = Stärke. weakness = Schwäche.
But ,,Schwachpunkt” is a litle bit different to ,,Schwäche“ (= weakness). ,,Schwachpunkt” are composed of schwach=weak and Punkt=point. So for example: If you punch someone in the belly and this is the only point he can´t resist so that is his ,,Schwachpunkt”.
If it is not clear to you or you have any questions you can contact me.