Agility is the power to move fast and with control — changing direction, speeding up, slowing down, and reacting instantly. It’s a key skill in almost every sport, like football, basketball, tennis, ...

Eyes ablaze with focus, the black-and-white dog heeds the start cue from her handler. She makes a jump, sprints up an A-frame, darts into a tunnel, shimmies through the weaves like a slalom skier, ...