Wallenda safety feature?

Saturday, June 16, 2012; 10:11:45 AM Eastern

I caught just a bit of Wallenda's daredevil walk across Niagara Falls last night.
But there's something that confuses me.
What's this cable connecting his body to the wire? Is it a safety feature?
I must have missed the part where they explained what this is for.

This is part of a restoration posts from 2012 and 2013. See these notes on the restoration. Last built: Sunday, July 8, 2018; 7:35:06 PM Eastern.