This is one of Dickens's main forms of exercise, at least during the daylight hours. Even if he's comfortably inside, the moment he hears someone or something moving down the alleyway he comes running to me, jumps up excitedly onto the side of my chair and gives me that "you gotta let me out! Now!!!" look. If I let him out (usually after whatever it is has passed the yard) he goes tearing off the deck, sailing through the air, and barks his fool head off while running circles around the shed and back along the fence. Then, when whatever it is out of sight, he comes trotting back up to the door, with a look on his face that says, "I guess I showed him!"
I think this is pretty harmless stuff, BUT, I don't let him continue barking past a certain point, I don't let him do it at night or early morning, and I don't let him languish outside making a pest of himself.