Abstract: A single-shock-use shock absorber having a first load application point; a second load application point; a deformable element between the points, the element being dimensioned for plastic shock absorbing deformation: and a bridge between the first and second load application points, the bridge dimensioned to fracture at a predetermined load less than that at which the element deforms plastically. Also provided is a single-shock-use shock absorber comprising a first load application point; a second load application point; a deformable element between the points, the element being dimensioned for plastic shock absorbing deformation, the deformable element having a first and a second slot extending into the deformable element from opposing sides. Also provided is a fall arrest device incorporating one or more of the aforementioned shock absorbers and a fall arrest system incorporating one or more of the aforementioned fall arrest devices.