How do I develop my horse's lateral quickness for cutting competition?

Lateral quickness in cutting is the physical quality that allows a horse to cover the distance between the cow's position and the blocking point faster than the cow can complete its change of direction — and it is one of those qualities that is partly genetic and partly developed through targeted training. A horse that is naturally quick-footed and light through its lateral movement has a significant advantage over one that is slower to shift its weight and change direction, but training can meaningfully improve the speed and efficiency of a horse's lateral movement even when it is not the fastest mover by nature. The foundation of lateral quickness is suppleness. A horse that is stiff through its barrel and hind end cannot shift its weight laterally with the speed that cutting demands because the stiffness creates resistance that the horse must overcome before it can move. Gymnastic exercises that develop lateral suppleness — leg yields, haunches-in, shoulder-in, and serpentines with frequent direction changes — build the physical flexibility that allows quick, fluid lateral movement. A horse that can move both ends of its body independently and without stiffness is a horse that can execute the quick, decisive cuts that define a great cutting run. Strength in the hindquarters is the second component of lateral quickness. The explosive push off the inside hind leg that drives the horse across in front of a changing cow requires genuine muscular power, and that power is developed through exercises that specifically load the hindquarters — transitions, hill work, and collection exercises that build carrying strength. A horse with weak hindquarters will always be slower in its lateral movement than its cow sense might suggest it should be, because the physical capacity to express the instinct is not there. Practicing quick direction changes in arena work — serpentines at the lope with minimal preparation between changes, figure eights with direct transitions at the center — develops the neuromuscular coordination that allows quick lateral movement to become automatic rather than effortful.