6 year old dog has the energy of a puppy!

My baby girl, an American Pitbull Terrier named Sadie, is roughly 6-7 years old. She was left in an abandoned house close to my former employer. She had had puppies but she had no access to food or water and the puppies died as she was so thin and malnourished she wasn't producing milk. She was about 3 when we got her out of the house that we watched her grow up running around in the yard with the other dog. She's sweet as pie and loves everyone that she encounters, just wanting to play and give kisses. She LIVES for the ball. Anyone that comes over gets 1 of her balls in their lap and a dance until they throw it; she just can't sit still. She gets so excited and has so much energy sometimes, even after a walk or exercise. People gasp when I tell them she is 6ish years old. Everyone takes her energy as puppy energy. She outplays the 2 year old lab. The vet says shes just a happy healthy dog. Anyone else have a dog over 6 that has more energy than most puppies?

I did. Chip, the 8-year old Dalmatian Tornado. If not for his size, no one would've ever believed his age. He put Marley, the Lab, to shame. Not much of intended destruction, but he mostly never wanted to come in, preferring to climb over the fence, the trees, the playhouse roof.... And at nights, he used to find it sooo difficult to fall asleep immediately. Even dozing, he'd keep thumping his tail- probably to burn out the day's quota of energy as much as he can.

He was one of those strong but lean missiles, no matter how much you fed him. That was the kind of nervous energy he used to burn. As to his kisses, there was this 'Kiss of Death' he kept reserved for my big bro, whereby he would proceed until bro's face threatened to collapse on the floor.....