My DS12 is already very fit and active - loves football, rugby, tennis, hockey, running etc. but he's keen to add in some weight training. I do weight training myself using dumb-bells at home - I started off with a PT but now just follow YouTube videos. Hasfit and Fit by Mik are my favourite as they give lots of info on form. I just wondered if these kind of workouts are safe for a tween or if there is anything I need to be aware of for him? Or if there are any good workouts on YouTube specifically aimed at this age group?