Big or small, any dog can participate in agility training. But, some breeds are better suited to the task, enjoying the fun of zipping through tunnels, leaping onto seesaws, and jumping over poles.

Patty Bensene, an Oregon City-based dog trainer, and Raven, her German shepherd, get ready for the agility competition at the upcoming Rose City Classic dog show in Portland. (Jamie Hale/The Oregonian ...