Thankfully the pilot wasn't injured, but this crash at Wisconsin's OshKosh 2011 EAA AirVenture air show looks quite bad—albeit a bit silly. [YouTube]
Well from my studies as a mechanical engineer, a majority of incidents like this stem from landing gear fatigue, now I cannot say what material the landing gear of F-16's is made of but a majority of landing gears (and most of all planes) are made from aluminum alloys. The issue here is that aluminum (and it's alloys most of them at least) do not have fatigue limits. That is that if you were to take a giant beam of aluminum and press on it with your hand a insane amount of time it would fail. SOOOO what happens with aircraft is the contact loading & unloading of parts such as landing gears fatigue over times and if not regularly checked for propagation of cracks it can lead to catastrophic failures such as this. This is why you often see tiny holes all over planes if you look closely they are drilling out small cracks to create a smaller stress concentration factor with the larger radius of the drill hole versus the sharp point of the crack's leading edge.
-The more you know!