Abstract: A helmet includes one or more pads on an inside surface of a shell, with the pads including a cushioning material that includes porous particles within a carrier liquid. The surfaces of the pores of the particles are lyophobic, resisting wetting by the carrier liquid. When the carrier liquid is placed under sufficient pressure, for example by an impact against the pad, the carrier liquid is forced into the pores. This causes the system to store and absorb energy within the carrier liquid. The pad may be made of flexible material with a pair of opposed major surface face pieces, with cells full of the liquid and particles extending between the face pieces. The liquid and particles may make up a majority of the volume of the pad, for example being at least 50% of the volume of the pad.