Watch as Coach Nick Kohl explains, and a long jumper demonstrates these BOSU ball stability drills. The focus of the drill is to work on the core and ankle stability. This is a controlled movement, raising the knee up and extending the foot. Make sure to work each leg for 8 to 10 reps. Beginners can lean against the wall or a coach so as not to worry about falling. Adding a weight held above the head takes away arm stability and turning the BOSU ball over makes the drill more difficult.