Shank

A shank is a rigid plate or reinforcement built into the midsole of hiking boots and mountaineering footwear, typically made of steel, carbon fiber, or dense plastic. It provides structural support and stability when walking on uneven terrain, rocky surfaces, or when using crampons, preventing the boot from twisting and reducing foot fatigue on long hikes. Full shanks offer maximum rigidity for technical mountaineering, while partial shanks provide moderate support for day hiking and backpacking on varied terrain.