An Ossur flex-run carbon fibre running blade with Nike sole. Appropriate for transfemoral (above knee) and transtibial (below knee) users participating in high impact activity such as jogging, trail and distance running and triathlons. To make the blade, threads of carbon fibre are woven into strips which are then layered (between 50 - 90 strips) within a mould and saturated with resin. After heating to fuse the layers and extract any air, the blades are cooled, cut to shape and tested before a prosthesist attaches a knee joint and socket. The sole has been designed to be easily removed and consists of four layers: a rubber waffle outsole made using Nike Grind (material recycled from the brand's 'reuse-a-shoe' programme), a polyurethane foam midsole, a cushioning layer composed of 'aeroply' (recycled Nike air bags), and a final nylon layer with tabs that lock the sole to the blade. Both Ossur and Nike worked with athlete and amputee Sarah Reinertsen, resulting in an extended blade at the toe for more powerful push-offs and faster acceleration, adjustments to the c-shaped curve to provide greater forward propulsion, and the replaceable sole where previously blade users had had to cut off the outsole from conventional running shoes to glue onto their prosthesis.