First, Bastian tested the funky walking on 40 healthy people. Sometimes, the treadmill moved their legs in opposite directions. Sometimes it moved one leg up to four times faster than the other.
With a 15-minute session, she essentially retrained them to walk with a lurch. No matter how hard they tried to walk normally when the session ended, they couldn't for 10 minutes or so -- until automatic nerve systems recalibrated themselves again.
There's a reason neuroscientists are interested in people with brain damage: just like engineering, putting things back together is awfully interesting. So is rewiring someone's brain, even temporarily, to take away something they've taken for granted since they were about a year old.