Researchers at the University of Louisville say four paralyzed men are now able to move certain muscles in their legs.

Doctors implanted an electrical stimulator on each of the patient’s spinal cords.

The device re-trains the nerves in the legs to work with the brain again.

With the stimulator, the four patients can flex their toes, ankles and knees on their own.

“This is just amazing for persons with complete spinal cord injury where in their diagnosis, their doctors probably said that they’ll never ever be able to move again,” Dr. Grace Peng said.

The device works by activating one leg at a time so the men cannot walk on their own.

But the success goes even further; the patients are regaining muscle mass and are recovering other functions otherwise lost to their injuries.

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