They can't quite walk. Yet. But four wheelchair-bound men who until recently were completely paralysed below the waist can now move their legs and toes and even lift up to 100 kilograms with their legs.

The team at the Kentucky Spinal Chord Injury Research Center now plan to test the device on a further 8 people, and work on a more complex version of the implant that will allow for the movement of both of a patients legs at the same time.

The New Scientist