@Forever:
This discribes zoey exactly. the crouch and pounce and the wearing out of dogs. She ran 3 italian grey hounds one after the other into the ground and was waiting for the next dog to come along so she can still play. Also whenever a new dogs comes to the park she plays greeter at the gate. People are always amazed at how fast she is.
Buddy plays greeter at the gate too and goes to the gate when anybody leaves. Buddy will run around hard for 1 hour or more at the park then when we get home he runs in the house and grabs his toy.