A collegiate runner , Zac Vawter had his right leg amputated after a motorcycle accident . In his first public appearance since then , he climbed 37 flights in about an hour . ` He has been equipped with a prosthetic that ascertains his intentions and then moves . Vawter climbs up Chicago 's Willis Tower in 53 minutes , 9 seconds . Comment:
A collegiate runner , Zac Vawter had his right leg amputated after a motorcycle accident . He has been equipped with a prosthetic that ascertains his intentions and then moves . Vawter climbs up Chicago 's Willis Tower in 53 minutes , 9 seconds . Comment: