Astle's Cadence project began two years ago in instructor Fridolin Beisert's INDU 08 Product Design 2 course. Beisert's brief for the course was deliberately vague: "Design an innovative product for the Olympics." As somebody who grew up active—running, swimming, surfing, skateboarding and, above all else, cycling ("I started riding a two-wheeler when I was three years old," said Astle) —the assignment intrigued him. As he began exploring ideas, the notion of designing a product for the Paralympics took shape in his mind. He relished the idea of focusing on an event that receives nowhere near the amount of attention as the Olympics, yet contains just as many dramatic stories of perseverance and triumph over adversity. Then it all clicked: he would design a prosthetic to assist para-cyclists, specifically for below-the-knee amputees, the biggest group of amputees in the United States.
Astle began his research by going to the Home Depot Center Velodrome in Carson, Calif. to observe competitive indoor cycling. While there he acquired several good leads for para-cyclists, conducted several interviews, and gained valuable insights into three challenges para-cyclists face:
A) Below-the-knee amputees experience a "dead zone" in the circular phase of pedaling because they are unable to create forward or backward movements;
B) Amputees have difficultly "clipping in" to a clipless pedal system—the system favored by professional cyclists that eschews pedals with toe clips for shoes with sole-mounted cleats that snap into the pedals—because they can't feel their way into the pedal's receptacle; and
C) Para-cyclists often fall when "clipping out" because doing so requires pivoting the ankle to unlatch the cleat from the pedal, an action which a below-the-knee amputee cannot do.
Over the course of 14 weeks, Astle developed his Cadence system that solves these challenges in a number of innovative ways. That dead zone due to a lack of forward and backward pedaling movements? Cadence solves this with an elastomeric band that accumulates potential energy—as the foot rotates to the bottom phase of the pedaling cycle, kinetic energy snaps the foot and leg back up and around to the top phase. The difficulty of clipping in without being able to feel if the foot is in the correct position? The Cadence foot features a split-toe design, so that para-cyclists can visually line up the cleat with the receptacle on the pedal. And the issue of para-cyclists falling while trying to clip out? Rather than relying on a pivoting motion to unfasten, the Cadence utilizes a magnetic system that disengages when the cyclist pedals backwards.
While a prosthetic that tackles as many problems as the Cadence does is reason enough to celebrate, Astle's design is so visually striking that it wows purely based on its aesthetics. "I didn't want it to look exactly like a leg, but I also didn't want it to look like a super-engineered piece," said Astle of his design that both echoes the dramatic lines and forms of a cycling helmet while also looking like a natural extension of the human body. "I wanted it to land somewhere in between."
And where exactly did the Cadence land? Everywhere. Last July it won IDSA's Gold IDEA award for Product Design. A few months later it won the U .S. James Dyson Award. And this July it will be on display in a special exhibition at the London 2012 Olympics. With all this attention, Astle's phone began ringing off the hook, with calls coming in from Brazil, Chile, Australia and New Zealand. "People were asking me, When is it coming out?" said Astle. "And then the prosthetics companies started calling me."