Strategy is more related to positioning yourself. It could be for a variety of reasons like increasing power in relation to market institutions, addressing the needs of a particular consumer segment etc..It involves designing a set of activities that will help you achieve this position.
However strategy is not just about achieving this position but also sustaining it. The sustainability is achieved through the Fit between various activities. A group of n activities can have a simple/consistent fit, a reinforcing fit or an optimizing fit. Either way the fit between these activities prevents repositioner or straddlers from draining away your advantage.
Mathematically: if there are n fitted activities. 0.5 is the probablity that a competitor can imitate any activity then the n activities drag down the possibility of imitation to 0.5^n