They require mental stimulation as much as they require physical exercise so activities such as earth dog trials, agility, tracking and fly ball are all high on a terriers list of favorites. (professorshouse.com)
She is an active competitor in a wide range of activities with her terriers engaging in earth dog tests, obedience, rally obedience, agility, and terrier trials. (amazon.com)
I find them amazing and often imagine that how on earth a dog could do that? (lovelybordercollie.com)