Inspired by mountain goats and their exceptional climbing ability, Klippa is a prosthetic leg concept designed specifically for amputee rock climbers. Its unique features augment human capabilities and challenge the limitations of existing prosthetic legs, allowing amputees to climb more efficiently and comfortably.
Mountain Goats, Nature's Greatest Climbers
Mountain goats are much better climbers than humans. After watching a YouTube video of mountain goats climbing a nearly vertical dam in Southern Italy, I did research on these natural athletes and found out about their uniquely structured hooves that help them stand on steep surfaces.
Hooves squeeze to grasp rock; split under pressure to apply energy more efficiently.
Hard, sharp edges add traction and soft inner area creates suction.
Rock climbing is a popular sport among amputees who maintain an active lifestyle.
Most prosthetic legs on the market are only designed for walking, not for rock climbing.
What's wrong with current prosthetic?
In addition to wearing climbing shoes to add traction, amputee climbers often flip their prosthetic foot because of its large size.
Passive articulation works well for repetitive movements like running. But for sports like climbing, it requires limited ankle articulation to adapt to different surfaces.
Rock climbing is a strenuous sport, and it can be difficult for amputees who are missing strength from their leg muscles.
User Interview +
To begin my research, I first went to a local rock climbing gym in Brooklyn and interviewed experienced two-leg climbers. These climbing experts provided many important insights on how they utilize their ankles, legs and bodies to keep their balance on the wall while climbing.
To further understand amputees' climbing experience, I strapped on some foam stilts to mimic of the effects of not having sensory feedback coming from my feet. I tried three different sizes, and in the end I discovered that the half-human-foot-size foam stilts allowed me to easily stand on small surfaces/rocks.
Climbing requires the use of toes. Having the right foot shape allows climbers to stabilize their bodies on the wall.
The result of my testing reveals that it is ideal to climb with a foot that is about half the size of an average human foot.
Elastic ankle joint with limited range of motion can potentially provide shock absorption and comfort for climbers.
This unique feature is one of the reasons why mountain goats are such good climbers. I would like use this feature in my final design.
Product Development Process
Using the insights from research as guideline, I began sketching, exploring color, materials and finish, and making prototypes (both exploratory and appearance). The end result is a cohesive design that embodies the aesthetic of a rock climber.
Elastic Pivot Joint
Klippa features an elastic joint to provide proper ankle articulation. The ankle pivots slightly forward when the pressure is applied to the tip of the foot. With the help of the elastic cord, the internal spring returns the ankle back to its starting position when the pressure is released. The elasticity of the joint provides shock absorption.
Under pressure, the hoof like sole expands and pushes outward, creating a strong grip between the sole and the rock surface.
The shoe is about half the size of an average human foot. Climbers can wedge their foot and perform heel strike with the textured heel.
The hard rubber shoe and shin guard provide stability and protection. They are also detachable so climbers can replace them easily.