Reebok Zig Shark Women's Running Shoes ZigTech Shark is designed to give you the springy, lightweight cushioning of the original ZigTech with a smoother, more comfortable ride. 20-degree backward angles along its zig-zag sole to preload the individual zig-zags encouraging them to bend backwards as the runner's foot contacts the ground for maximum cushioning. To maintain the springy, lightweight cushioning, Reebok has kept the bottom construction mainly a foam platform. Also added are small segments of rubber in the forefoot and the heel for durability and traction.