Differential-stiffness impact-attenuation members and products including them

A foot-receiving device comprising:

• at least one of a foot-covering member, a foot-supporting member and a surface-contacting member;
• and
• at least one impact-attenuation member engaged with the at least one of the foot-covering member, the foot-supporting member and the surface-contacting member, the impact-attenuation member comprising:
• at least one spring element defining a cavity, the spring element having dimensions in height, length and width directions, the height dimension extending from a top surface to a bottom surface, and having at least one of the top surface and the bottom surface adapted for mounting, the length dimension extending from a front end to a back end;
• and
• wherein the impact-attenuation member has a first stiffness in the height direction at the front end of the spring element and a second stiffness in the height direction at the back end of the spring element, the second stiffness being different than the first stiffness;
• and
• further comprising a tension element extending across the width dimension of the impact-attenuation member between a first engagement portion engaging the spring element and a second engagement portion engaging the spring element.

A method of using an impact-attenuation member, the impact-attenuation member characterized by mutually perpendicular height, length and width dimensions, the length dimension extending from a front end to a back end, the impact-attenuation member having a spring element and a tension element extending across the width dimension of the impact-attenuation member between a first engagement portion engaging the spring element and a second engagement portion engaging the spring element, the method comprising:

• decreasing the height dimension of the impact-attenuation member at the front end as a function of a first spring constant;
• decreasing the height dimension of the impact-attenuation member at the back end as a function of a second spring constant, wherein the second spring constant differs from the first spring constant;
• and
• increasing a distance between the first and second engagement portions, thereby stretching the tension element.