To keep a dog's body strong and healthy for a lifetime, two properties of muscle must be maintained- strength and flexilibity. Strength is power. The muscle contracts (shortens) and power is created to propel the dog's body. Repeated muscle contractions over time tend to cause the muscle fiber to remain in a shortened position. More power is created by a longer muscle fiber. A shorter muscle creates less power. If the muscle stays shortened, a downward spiral of weakness begins. The body must still move, but now with less power. A muscle asked to do more than it has the power to do will breakdown and tear. A tight or shortened muscle will also cause joint problems. This tightness can create uneven pressures on the cartilage in the joint. This causes uneven wear that over time leads to degenerative changes and predisposes to arthritis.
Stretching returns the muscle fiber to its elongated state. This helps maintain strength and joint integrity. Dogs seem to know this. They stretch themselves as best they can on their own. But there are many muscles a dog simply can't stretch on his own. That's where we enter the picture. We can stretch the muscles of the neck, back, shoulders, hips, knee (stifle), even their toes. Not only will it feel good to your dog, it will help him keep him healthy and reduce his chances of getting injured or developing arthritis.