US Patent 7398609 Skate boot

A skate boot for enclosing a human foot when in use, the foot having a heel, an ankle with a medial malleolus and a lateral malleolus, an Achilles tendon having an upper part and a lower part that projects outwardly with relation to the upper part, the lower part merging with the heel, a plantar surface, medial and lateral sides and toes. The skate boot comprises an outer shell and a tendon guard affixed to the outer shell. The tendon guard is more flexible than the outer shell such that it allows backwards flexion of the ankle when the foot moves towards full extension.