It is a balance act between flexibility and strength that lies at every skill. The flexibility has though a kind of priority. Then the strength is related to the inertia. Flexing goes as far as the strength allows. The limit of the flexibility is not the strength but the strength has to serve as a frame in which the flexibility can flex without collapsing the system. Training is always negotiating between them and trying to maximize flexibility while intensifying the strength but making it almost passive or hidden.