In relation to inflatable boards, we consider both static and dynamic loads. When standing motionless on the board, bend or flex is determined purely by load (gravity) acting downwards on the board. This is said to be static load. When paddling, compression downwards from the rider during the act of paddling, particularly at the entry and catch phase of the stroke, exerts a dynamic load which combines both the weight of the rider and the resulting downward force created through paddling. The board therefore flexes and thereafter springs back to assume the static load position during the exit and recovery part of the stroke. By conjoining x 2 narrow chambers, flex is significantly reduced as a consequence of reducing the total surface area of each. Narrow width chambers can be made stiff, whilst wider chambers are harder to make stiff. In tests, a ‘regular’ inflatable with 75kg static load, bends @9cm but only @3cm with Mistral’s Twin Air Technology®.