09/20/2023
As your dog retrieves the first...second...third...maybe fifth or sixth ball, his muscles start to tire and soon they reach overload, where they no longer can fully control and support your dog's movements. Now, when your dog does those amazing athletic maneuvers to snag the ball, soft tissues like the cranial cruciate ligament, iliopsoas muscle and tendon, and the muscles and ligaments that support the vertebrae are overstretching. Minor tears are occurring. Now the ball is thrown 10, 12 times or more and ultimately your dog lies down, exhausted.
That period between when your dog's muscles are in overload, and when your dog lies down exhausted, is the injury zone (Figure 1). But remember, with all that adrenaline, your dog doesn't feel the injuries happening, so you have no idea that the tissues are being used beyond their capacity.
When this game is repeated day after day, month after month, the small tissue tears become large ones, and suddenly it becomes evident that your dog is in pain and has an injury. Of course, it hasn't been sudden at all-what seemed sudden is just the final result of repeated stress and strain until the tissues gave way.
Chris Zink DVM
Discovering Your Dog
