It may not be obvious, but the front of the frame is resting on the ground, and the crossmember between the seat rows (2nd permanent) is suspended by a single point in the center. This shows just how flexy a '92-96 Bronco frame in perfect condition actually is. F150s flex even more because they're longer than Broncos. Heavier pickups have thicker frames, but they still flex.
All the truck's torsional rigidity comes from the body, which is why Broncos that do a lot of miles off-road can tear the sheet metal.
The early Bronco's fully-boxed frame ('66-77) flexes almost identically.
