My 3 year old is soft, generally laid back, and a little environmentally cautious (we must examine and understand new places before we are comfortable). Last week we went to a dog camp and discovered lure coursing. She literally screams when she sees the "bunnies" or hears the whir-clicking of the coursing machine. Elsie is a wild beast in the presence of the lure-machine, yet remains her normal self when no plastic "bunnies" are in sight. Introduce young Tank to all sorts of fun and adventures. You may find something that rings his bell. Weight pull and agility are other sports that turn on many dogs. If he like water/swimming, dock-diving is another. In my experience, many Pitty-types are not fans of the H2O, though.
Tank is adorable. You'll find his bliss...