A ski boot comprises a rigid outer shell and an inner shell which is relatively flexible. The inner shell features a relatively flexible saddle region which extends over the metatarsal and/or instep portions of a wearer's foot. Tensile elements, such as cables or straps, extend over the saddle and cooperate...http://www.google.co.uk/patents/US4949479?utm_source=gb-gplus-sharePatent US4949479 - Ski boot having variable volume inner shell
