Man climbs one of world's tallest skyscrapers using bionic leg

Zac Vawter, who lost his leg in a road accident in 2009, reached the top Willis Tower in Chicago in under an hour with no breaks, making his way up 103 flights of stairs on the revolutionary prosthetic leg.

The robotic leg responds to electrical impulses from muscles in his hamstring, with his thoughts triggering motors, belts and chains to synchronise the movements of the prosthetic ankle and knee, the 'Daily Mail' reported.

Researchers from the Rehabilitation Institute of Chicago (RIC) monitored his progress but believe the incredible technology is still a few years away from being marketable.

Thought-controlled prosthetic arms have been available for years but with leg amputees outnumbering people who have lost arms and hands, researchers are focusing more on lower limbs.

"Before the accident I loved to run and afterwards I didn't think I would ever be able to be so active again.

"Mentally and physically I felt prepared for the climb, so it was kind of what I expected. I got a real kick out of it and felt really strong. I made it in excellent time with no issues," Vawter said.

Zac and the scientists spent hours adjusting the leg's movements to prepare for the climb. Eleven electrodes placed on the skin of Vawter's thigh fed data to the bionic leg's microcomputer and researchers turned over the 'steering' to him.

Behind closed doors he was able to kick a football, walk around a room and climb stairs.

During the operation, a surgeon repositioned the residual spaghetti-like nerves that normally would carry signals to the lower leg and sewed them to new spots on his hamstring.