My older dog 1.7 yrs now is still as energetic as he was as a pup. NOTHING gets this dog tired, he has boundless energy. We walk him at least 3 long walks a day, play with him, let them run in the yard with toys, MANY MANY safe toys, I give him bully sticks to chew and stay busy. Honestly there is almost nothing I can do that will tire this dog out but we try.
We got our puppy (7mths now) to keep him busy too, so he had a playmate. That worked out great for us, but she tires out much more quickly than him and she naps and relaxes while he paces the rooms. But overall for us this helped a great deal, when she cant play with him, we do.
We even bike with him. My hubbie takes him next to him with a leash and we bike with him, he can run faster than we can bike, its crazy. One night we went 4 miles on the bike (stopping to give him pee stops and water) and you think this would tire him out? NOOOO He came in after his 4 mile run and proceeded to grab toys and run around. So my point is...some dogs are boundless but you do the best you can.
I have been thinking about getting a treadmill for doggies that I can maybe try him on with my total supervision, so he can walk and walk and finally let out that big boy puppy energy.
Safe toys and safe chew sticks and lotsa walks!!! That is the best thing youc can do! And play with the pupp lots too.