Spring-Powered Leg Brace Puts Stroke Victims Back on Their Feet
Donna Jang takes ballroom dance lessons, using the Kickstart to help her move.
CREDIT: Cadence Biomedical
After Donna Jang of California suffered a stroke in 1992, walking was extremely painful and sometimes impossible. Today, she's ballroom dancing, thanks to a device called the Kickstart Walking System, a leg brace that helps people with neurological injuries regain movement.
The Kickstart operates without motors, batteries or electricity of any kind. Instead, the device uses a pulley system and a long spring aligned to the front of the leg.
In this way the Kickstart aids the hip flexor muscles, which control the motion of the hip and upper thigh and are critical to walking.
When wearing a Kickstart, the act of pulling the leg back or the hips forward stretches the spring, and then that coiled energy is released when the leg is lifted, causing the spring to contract and help power the leg forward. [See also: Human Minds May Soon Control Prosthetic Limbs]
Walking becomes easier after the first few steps, as the user builds up kinetic energy from the body moving forward.
The design was inspired by horse anatomy, explains co-creator Brian Glaister. "Horses have stretchy tendons [in their legs] that stretch around their bones and store energy so their muscles don't have to work as hard to move their legs," he told TechNewsDaily.
The Kickstart was designed to help people with neurological injuries or other conditions that drastically decreased their motor control, such as strokes, spinal cord injury or multiple sclerosis.
Glaister said patients often ask him why nobody thought to make a spring-powered walking aid before.
"Honestly, I don't know," Glaister said. "It's a very simple idea but it's very powerful, and consistently getting people who've had injuries five, 10, 20 years ago back on their feet."
Kickstart is an orthotic, not a prosthetic, meaning it attaches to and assists the existing limb instead of replacing it. However, the Department of Defense's Joint Warfighter Medical Research Program recently awarded Cadence Biomedical, the company that makes the Kickstart, a grant to develop the orthotic into a full prosthetic. [See also: 3D Printing: From Doodads to Prosthetic Hands]
The prosthetic would move using the same spring-powered motion, with some added electrical features. For example, many amputees find it difficult to judge the distance between their prosthetic limb and the ground.
New Kickstart models will include sensors beneath the appendage's foot that, when activated, cause vibrations at the location where the prosthetic connects to the body. The vibrations let the user know that their foot is on the ground.
The grant also covers other sensor equipment that will help Cadence Biomedical gather data on patients' use of the Kickstart.
Some type of therapy or training is usually required to make full use of the Kickstart, but Glaister says that many patients instantly benefit from the device.
"It's really exciting to have someone wheel in on a wheelchair and strap on a Kickstart and five minutes later walk out."