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Arizona State University Develops the SPARKy Springy Prosthetic Leg

Researchers at Arizona State University have developed the SPARKy prosthetic leg, a device that uses energy stored in a spring while walking.  The lightweight prosthetic provides a much wider range of motion than traditional prosthetics while reducing fatigue.  It allows users to walk on a wide variety of surfaces, traverse stairs in both directions, and even tackle inclines, thus permitting a return to most normal activities for many people wearing the new leg.

Weighing around four pounds, the spring ankle with regenerative kinetics device  is lighter than most prosthetics.  The new below-the-knee prosthetic takes advantage of the mechanics of the natural gait which consists of two components: stance and swing.  In the stance phase, the foot in planted on the ground and pushes off into the swing phase where it moves to the next ground position.

SPARKy stretches a spring in the position of a healthy Achilles tendon. The spring captures the energy generated as the foot breaks the fall of the leg as it reaches the ground at the start of a stance phase, storing it as the ankle rolls over the foot. That stored energy then propels the foot forward for the next step, greatly increasing the power of that step. Small motors in the foot provide tiny adjustments to the spring to regulate the gait and position the spring for maximum efficiency. Researchers claim that the range of motion and power provided by the spring is roughly equivalent to the normal gait of a person with two natural legs.

Funded in part by a three year grant from the United States Army, the eventual goal of the SPARKy project is to restore enough functionality to amputees to allow them to return to active duty.

Read more about SPARKy in the press release from Arizona State University:


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