I've been teaching our 4,5 & 6 year olds for quite a while now. First of all, don't underestimate what they can do. However, you have to keep your class fast paced and with a high energy level. I never spend more than 4 minutes on a particular drill or section of class because they have attention spans the size of a gnat. Who cares if you didn't get all the kicks in, go to something else and then come back to it. Also disguised repetition or adding something fun to your normal drill will keep them tuned in to your class. You as an instructor have to be animated and vary up your pitch and voice level. Make class fun and exciting not only for the kids, but the parents as well (they are a very important audience as well!!!) One last thing to end off with it: I often see that too many instructors get too focused on the technical aspect of the karate class. First of all, this age group doesn't quite have the motor skills and are still developing. Second of all, more than likely Mom and Dad want their kid to develop focus, respect, self-discipline, etc. The martial arts is merely just the way to teach all those qualities in a fun way. So what if they don't know the difference between a front kick and roundhouse or when they try to do a form ithey looks like a cat in a bathtub, but if they used self-control- stayed on their feet and showed self-discipline for keeping their hands up then it's a successful day. Have fun with it, even though this group demands a lot of energy and wears me out they are one of my favorite and most rewarding groups to teach