This activity is pretty straightforward in theory; it aims to help your dog become stronger by urging them to train with various amounts of weight. As with human weight training, it's important not let your dog bite off more than they can chew early on (unless you want your puppy to end up in one of those "gym fails" videos that are all over the web,) so start off light and then help your dog gradually working with more weight.
Doberdanes are pretty brainy breeds, when all's said and done. To help your dog become much more well rounded, we think it'd be a good idea to expose them to a few dog puzzles so that they can train the greatest muscle of all - their brain. Dog puzzles come in a variety of shapes and sizes, so look around for the ones that best fit your Doberdane.