If you play percussion you are doing variations in dynamics all the time at extreme speed - that's how you put life into the beat pattern. The audience is hardly ever aware that you're doing it, let alone how. Touch a drum head with your hand or the non-striking stick to mute it, press down on a washboard to stop it rattling freely, open and close your hand round a shaky egg, tilt a tambourine to control how much the jingles move, use a stick with a different tip material, pick a different strike point on just about anything - how hard you hit is only a fraction of the story. You will easily get several planned, consistent, reproducible changes in dynamic level within a second.