Three-round interval drill using an exercise ball (or block) for side-to-side windshield wiper leg swings, lifted leg circles, and a dynamic boat-style curl-and-launch. Work 30 seconds on, 30 seconds off. Builds deep, adaptable core strength while stabilizing pelvis and spine. **Benefit:** Core strength and control for jump-backs, jump-throughs, and lifting up into headstand; develops the hip and abdominal integration needed for smooth, effortless transitions.​​​​​​​​​​​​​​​​