When our little mixed breed dog Quixote awakes from a deep sleep or even a nap, he does two stretches, in this order. First, he does an exaggerated play bow where he extends his front paws, bows down and raises his neck slightly. This is followed by a maneuver of extending his back legs behind him like a hairy, horizontal version of a ballerina who goes on point.

Why do dogs stretch when rising?

According to Jonathan Rudinger, the Toledo, Ohio-based author of "Effective Pet Massage for Dogs" (www.petmassage.com), this is just warming up their muscles. It also puts the joints into proper position and gets everything in balance so they're ready to move.

The joint surface gets nutrition through use. The pressure and release action pumps the joint fluid in and out of the cartilage bringing in nutrition, and removing waste products. Stretching maintains the health margins of cartilage that don't get used in routine movement.

"The reasons why dogs stretch after a period of inactivity are most likely multifactorial," says veterinarian Dr. Narda G. Robinson, head of the complimentary and alternative medicine service at Colorado State University's Veterinary Medical Center. She cites studies that show joints needing movement in order to stay healthy. "When we put dog limbs in casts, some of the joint cartilage will disappear in a matter of weeks." Thus, it is instinctively advantageous for dogs to restore their range of motion by doing "doggie yoga" after a long nap.

Stretching also causes tendons to become more compliant, in the event that sudden high-intensity movement might be required. From an evolutionary perspective, we can imagine that a wolf waking from a period of rest would be best prepared to catch dinner if she first fine-tuned her instruments of locomotion.