Abstract: A sit up exercising apparatus has a seat assembly, an actuating bar The seat assembly has front leg, a cushioned seat and a rear leg. The actuating bar is attached pivotally to the seat assembly and provides an elastic force to assist a person using the sit up exercising apparatus and has multiple rollers. The rollers massage a person's back who is using the sit up exercising apparatus. Consequently, a person's backbone is not likely to be injured, and the exercising force can be adjusted to accommodate individual users based on their age or physical condition.

Abstract: This invention is directed to a new approach to form porous hydrogel materials by first creating gas pockets in the gel and then removing this gas. The removal of the gas creates a porous material, and the initial incorporation of sufficient gas allows one to create a material with an open, interconnected pore structure. Advantageous features of the resulting materials, in addition to their interconnected pore structure, may include that the pore structure is maintained over extended time periods and that the gels maintain a high mechanical integrity that allows seeding with cells and implantation without destruction or compression of the material.