Nature article on why basketball sneakers squeak.
Summary of the Nature article from Beyond Euclid:
"High-speed cameras showed the rubber sole rapidly snapping and slipping against the floor on impact — hundreds of tiny wave pulses, similar to fault ruptures in earthquakes. The tread pattern forces these into regular intervals, producing a steady pitch instead of noise. Flat sole: random noise. Patterned tread: something close to a tone."