Performing low repetition/heavy weight workouts will enable you to build muscle mass, however they will only do so for a very short period of time. The reason is that your body is always striving to maintain homeostasis, other wise know as the status quo, or to remain the same. Your body is not interested in building muscle mass, and in getting bigger and stronger, your body is interested in survival and in avoiding change. In order to do this your body has developed many mechanisms that allow you to quickly adapt to a host of possible stimuli