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From VOA Learning English, this is the Technology Report. Electronic devices that help people walk were once thought to be difficult to design. Until recently, such a device required electricity from an external power supply. Now scientists have built a small, wearable addition to normal shoes. Their new invention eases the load on muscles in the leg and makes walking easier.
Steven Collins and Greg Sawicki are biomedical engineers. Steven Collins works with Carnegie Mellon University in Pennsylvania. Greg Sawicki is with North Carolina State University. They both studied how human beings walk. They found that our ankles and calves perform motions similar to a spring joined to a clutch. In an automobile, a clutch is used to connect and disconnect a driving or driven part of an engine. The researchers found that those human body parts are able to both store and release energy, just like a spring. Mr. Sawicki says they designed a mechanical device that performs a kind of energy ‘give-and-take’ outside the body. Their new ankle exoskeleton device is made of carbon fiber and metal. It connects to ordinary shoes and takes over part of the work of walking. Mr. Sawicki says the unpowered device reduces the amount of energy required for walking by as much as seven percent. Mr. Sawicki says it takes only a few minutes for someone to get used to the ankle exoskeleton. The unpowered ankle exoskeleton can help people walk farther. It also can restore normal movement for individuals who have trouble walking. He says the device is mainly meant for people recovering from an operation or a stroke.