The paper deals with the low power design of synchronous finite state machines (FSM) concerning a given sequence of primary input signals (pattern). It is suggested a novel and practical synthesis approach to reduce switching activity by disabling particular self-loops combined with an appropriate state encoding. The required analysis of the FSM behavior with respect to the pattern sequence is performed by an underlying profiling step. The experimental results show that power can be considerably reduced but the obtained reduction depends decisively on both, the FSM structure as well as the pattern sequence.