The basic concept is that horizontal load transmission from the playing surface to the foot is controlled by having a specially engineered sole.
The design is actually two soles stacked on top of each other, essentially a split sole with a low-friction, spring-loaded interface.
The lower sole provides the interface with the playing surface, and the upper sole provides the interface with the part of the shoe upper that holds the foot. The load transmission across the interface is controlled by specially designed springs connecting the two soles.
Video of the sole technology
The physical design solution (PDs) includes a special system of springs, retaining elements, and sliding interfaces that are carefully integrated into the sole of an otherwise normal sports shoe. This multi-component sole modification allows displacement, under approximately constant load, in three directions (fore-aft, medial-lateral, and vertical).
Rotation can take place in the horizontal plane about any vertical axis, simultaneous with lateral displacement, avoiding the problem with a single vertical axis of rotation, as seen in most ski bindings, that leads to ACL injuries. Rotation is inhibited about a fore-aft axis to maintain normal support.
During the sole displacement, a special spring system absorbs potentially injurious loads when the shoe is in contact with the playing surface. The stored elastic energy in the spring is used for the recovery of the sole to its normal, unloaded configuration.
This displacement design provides an important advance over systems that release. Every doubling of the displacement can reduce the peak loads by a similar amount. This system is limited in that it cannot influence loads unless they are transmitted through the sole. The potentially injurious loads must exceed ordinary playing loads. It cannot protect against loads due to muscular activity, e.g. contraction of the quads, which can apply significant loads across the knee without loading the sole.