I've worked my entire life practicing the rudiments. Sure, I've worked on single strokes. Who hasn't? But lately, I've been working on the single stroke exercises at the back of Ted Reed's Syncopation. Eighth notes, triplets, sixteenths, with all the accent variations, and playing the accents on various parts of the kit while feathering the bass drum. Man, it gets you in shape. Most of what you play on drums with be variations of single strokes. I'm putting a lot of effort into that part of hand development.