My son, 9 years old, wants to do some weights to build himself up a little. He is ultra-thin, but eats a fairly healthy diet, and is very active - Karate 2-3 times a week, swimming and Swimming Club league meetings 2-3 times a week, lots of bike rides, football, golf, etc - and we've got to find time to do weights as well! maybe twice a week to begin with. Anyway, for practical reasons it's dumbells only for now. Has anybody got any ideas for a session? I'm not too bothered about the weight of the dumbells, we will build that up over time, and I expect him to be doing sets of 12-15 reps of each exercise. So, what exercises should he do to cover the main muscle groups? Many thanks.