Shanks are rigid members embedded in the midsole of footwear to increase wearer comfort. Different types of footwear value different shank parameters. While a work boot requires a very stiff shank with immense puncture resistance (usually steel), a leather dress shoe only requires a shank to maintain the shape and aesthetic design of the shoe (usually either steel or hardwood). In this project, three environmentally friendly shanks have been fabricated for the use in Forsake (a small footwear company founded by two Union College alumni) “Trail” model hiking boots. These environmentally friendly shanks are made of thermoplastic carbon fiber and a pre-impregnated flax biocomposite. Forsake installed the environmentally friendly shanks in their factory to remove the variable of manufacturing from the study. Three tests were conducted between the legacy nylon shanks and the three shanks fabricated for this study: shank longitudinal stiffness, aerobic performance (heart rate), and gait alteration. The theories being tested are whether the stiffer carbon fiber shanks perform better than nylon, and if the flax biocomposite could also be a suitable replacement.