Its curvature ensures your upper back extends that bit further down to the floor. This gives you a great stretch through the abs at the bottom of the movement, while supporting the lower back and maintaining correct lumbar alignment. By using the classic aircraft wing shape, you get a gentle curve at the back, and a steeper incline on the front edge. This mimics the curvature of the lower spine.
When designing our ab mats we only put in the best materials. Why use a soft foam core that simply squashes down to nothing? We use a firm foam core that maintains its shape, ensuring the mat performs exactly as it should. We also use a rip proof synthetic vinyl shell, which is just plain thicker than the others, and as a result is difficult to tear.