Impact-protection slip-plate structure and methodology involving (a) a generally planar, plural-layer, outside-jacketed, shock-absorbing barrier assembly positionable relative to the human anatomy in a location adjacent a body zone to be protected, and (b), disposed within that assembly, a generally planar, friction-reduced slip-plate organization including a pair of facially confronting, generally planar slip-plate sub-structures disposed on opposite sides of a friction-reduced slip plane, responsive to an impact occurring along a line which lies at a angle other than normal to the slip plane to produce relative-motion impact-initiated slippage of the two slip sub-structures with respect to one another along opposite sides of the slip plane.