I tried flyball with Brodie... I thought he'd LOVE it since he loves all things fast and all things fetch and carry.
My VERY snobby sheltie apparently will not mouth a ball that has another dogs spit on it.... who knew??!!!! Of course, this is my same dog who will NOT eat food from 'strangers'.... "stranger danger!". Yup, he gingerly takes, then spits out unless I give him treats.
Deacon will eat anything, but is very against all things exercise. If he clues in that an activity is good for him, he'll stop. Fetch and Frisbee are all good and fun if he's only focused on annoying Brodie and trying to steal things from him. The minute he figures out he's exercising, he's done.