I was so messed up, stiff, basically locked from pain when i got Victor. Out of desperation to get his beyond hyper activity down to a level that would not destroy us I took him to the park and made my goal to walk to the baseball diamond and back. It has been a long time since I had even attempted to move much at all. Victor in the mean time ran about 3 miles in circles around the valley. By the time i got back, about a block's distance, he had had the time he needed. It was good for me. Moving helped ease the pain in my joints and seeing him run is pure poetry and that was the best medicine of all for my soul. I can't see that being any being any different. If I hadn't found a place where he could run off leash, that might have been another story but I did. So maybe it is the same for someone in pain doing agility with their dog.