the forefoot portion 16 couples to the intermediate portion 12 section e e is taken at approximately the midpoint of the intermediate portion 12 and illustrates an intermediate portion 12 substantially narrower than the forefoot portion 16 section f f is taken at approximately the midpoint of the rearfoot portion 14 and illustrates a rearfoot portion 14 forming a centrally disposed aperture 24 another embodiment of a torsion system 50 according to the present invention is shown in fig3 the torsion system 50 may be a single plate 110 having an intermediate portion 120 with reduced lateral dimensions which allows twisting of the forefoot portion 160 of the torsion system 50 and thereby of the footwear relative to the rearfoot portion 140 the resistance and twisting of the torsion system 50 in the intermediate portion 120 defines the torsional flex of the footwear a defined torsional flex can also be achieved by constructing the intermediate area 120 thinner than the forefoot and rearfoot portions 160 140 or with a material with different mechanical properties than the forefoot and rearfoot portions 160 140 in addition apertures 21 may be added to the intermediate portion 12 in the embodiment depicted in fig3 the i beam element or rib 20 has been replaced by two apertures 21 it.