This Balance Bridge is not to be confused with the Balance Bridge from SASUKE, appearing in the Miami regionals of American Ninja Warrior 5.
There were two thin cylindrical beams that are both on a pivot in the middle. The competitor must jump onto the first beam, which will tip down and walk up to the end, where it'll tip down. Then jump over a gap to the second beam which'll tilt down too. They'll have to get across this and dismount to the landing platform but, if they lose focus, the tilt on the bridge might mess them up.
This obstacle eliminated a couple competitors, on the bridge switch and the dismount.