Ever wanted to run like an ostrich? When Keahi Seymour was a teenager, he decided to create shoes that would let him emulate the birds’ springy gait and match their top speed—45 miles per hour. Many years and a dozen prototypes later, Seymour came to Maker Faire to show off the latest version of his “bionic boot.” This prototype boosts his pace to a brisk 25 miles per hour, but Seymour won’t rest until he can take the human body to the next level, and outrun some of Earth’s fastest land animals.
To strap on and run with the Bionic Boots is a feeling like no other. As you begin to stride, you feel the springs storing energy. Then you push off, and you feel the enormous power released, akin to acquiring your own slice of a superpower.
I built the Bionic Boots simply because I wanted that experience. Ever since I was 12 years old, I’ve been dreaming of one day dropping into the African savanna and running with cheetahs.
Initially, the concept was to emulate and experience the sensation and speed of running like a fast animal. I still have the same goal, but the invention is evolving through the use of future technologies to reach new endeavors. I want to produce a viable form of environmentally sound transportation over any terrain, be it city streets or off-road trails — and to run faster than any man alive.
The first spark of inspiration came from watching a natural history program on kangaroos and how they were able to store energy in their large Achilles tendons, enabling them to move at high speed over difficult terrain with an efficient gait. I made my first drawings at 12, and the inventions that came along years later were not too dissimilar to those originals.
A quarter century later, I’m on something like the 200th prototype. These boots are made from aluminum and carbon fiber, with elastic tendons. In them, I stand 7 feet tall, and can run 25 mph.
In the intervening time, I went to college and moved, in 1999, to America. I studied transport design and won a Royal Society for the Arts award for the boots, and used that grant to go to California, the birthplace of so many recreational sports (mountain bikes, skateboards, fiberglass surfboards) and to bring the Bionic Boot into the public domain.
I already had an aesthetically pleasing and working prototype, but it would be one of many. I tend bar six days a week to pay for patent fees and material costs and have worked up to the X14 (2014) prototype.
The boots work by basically giving plantigrade (that is, flat-footed) humans a mechanical advantage, allowing them to run on their toes in digitigrade fashion, the way fast land mammals such as greyhounds and cheetahs do. By raising me on my toes, the boots lengthen my legs and stride, which increases speed and efficiency.
There are two levers, a main one and one for the toes. Both are attached to rubber extension springs that mimic the aforementioned kangaroo tendons. The main lever provides the majority of the propulsive force. As the boot lands, the 18-inch lever stretches the springs; then as they contract, the lever swings through a pivot past the heel, propelling the main lever and springing the user like a catapult. The smaller toe lever has a rubber and foam grip, which gives purchase over uneven terrain. Depending on the conditions, one, two, or possibly three interchangeable toes with differing sizes and tread patterns can be added.
To build the boots, I leveraged metalwork, carbon-fiber molding, and spring building. The initial main boot was designed and constructed by making an anatomically correct copy of the boot itself. Later, my friend Carl Riccitelli made a mold of it, and laid carbon fiber into the mold to produce the current prototype with the best strength-to-weight ratio so far.
Aircraft grade aluminum (6061 and 7000 series) was used for the other major components. All were constructed without the use of CNC milling machines or casting methods, but instead were cut, shaped, and polished using only a hand drill, angle grinder, and hacksaw.
The spring system is made of natural rubber from speargun spring bands, cut to specific length, with custom-made grommets to attach to the rubber. These can be added or subtracted to adjust for the weight of different users or the running style or cadence desired.
My invention has been designed — and has evolved — for fast running as a form of transportation. While the top speed is formidable, the stilts are not designed for maneuverable running (i.e. turning).
I am not the only inventor to design augmenting boots. There are other proto-types and products that use different spring systems, though my invention pre-dates the patents on the most similar ones.
One example, originally sold as Powerbocks (now Pro-Jumps) from Germany, also uses a pivoted lever to add stability, but is designed more like traditional stilts, allowing you to jump vertically like a pogo stick. Young athletes use them for parkour-style extreme sports. (Not to be confused with kids’ springy Moon Shoes, which simply suspend the feet in oval frames, like two trampolines.)
The differences between the two are not only in the main function but also in the spring: The Pro-Jumps use a fiberglass leaf spring, whereas mine feature natural rubber as an extension spring to store potential energy. Additionally, because of the material, the Bionic Boots weigh in at just six pounds, around two pounds less than the Pro-Jumps.
But one feature that is truly unique is the pivoted toe, which gives the landing some dampening from the stiff impact of the large spring, as well as maneu-verability and extra purchase on uneven terrain. I’ve used them on everything from potholed and cobblestoned streets in New York and London to California beaches, peaks in the Rocky Mountains, and even in shallow water.
Farther and Faster
There’s still a lot to do, future improvements to the Bionic Boot to extend the distance and speed. I’m planning an onboard electronic feedback control system to help coordinate the power and propulsion to give the most effective timing of power output throughout the running cadence, thus providing maximum efficiency and power expenditure. I’d also like to explore 3D printing, specifically with titanium or carbon fiber — even a 10 percent weight reduction could give incredible results.
Collaboration with companies like Local Motors, which printed a car with carbon fiber-infused ABS, or Renishaw, which printed a titanium bicycle, could help improve the boots’ performance.
The “muscles” could be adapted too, perhaps to include pneumatics like Festo’s “fluidic muscle,” which enabled that company’s Bionic Kangaroo. It uses pneumatic pressure to contract the muscle as air is added. In nature, a kangaroo recovers energy from jumping and stores it for the next leap. In a boot, that could mean greatly increased speed and distance.
In the end, the Bionic Boots could become a whole interlinked exoskeleton built solely for speed, approaching that of an ostrich or even a cheetah.
I can see a vision of a prototype I sketched many years ago, encompassing a full-powered protective suit with onboard readouts of speed, distance, system power outputs, and more. It’s my bionic conception of future transportation.