Weighted Hollow Rock

Lie on your back and pull into a hollow position: lower back pressed into the floor, shoulders and legs lifted a few centimetres off the ground, arms extended overhead holding a single dumbbell between both hands. Your body should form a shallow, banana-like curve from fingertips to toes. From that shape, rock gently back and forth along your spine, using your core to control the motion rather than letting the dumbbell swing you around. If your lower back lifts off the floor or arches, the rock has gotten too big; bring it back to a size you can control while keeping that curve locked in.