Casio made a giant breakthrough in 2008 by offering the first high performance
, high speed video camera, the Ex -F1. Casio followed with the FH20, FH25 and the FH100 (in 2010). The market did not appreciated these cameras with manual shutter speed control to minimize motion blur and instead purchased high speed video cameras with high frame rates but none of the other powerful performance features. The Casio advertising was not technically attuned to communicate the superior features of these cameras. Now, to my knowledge, no
manufacturer is offering an affordable high performance HS video camera with MANUAL exposure control. Those offered have AUTO exposure control, often only record for short times in high speed video mode, have more Jello Effect, etc.
Sports action? I analyze tennis strokes with a Casio FH100.
If you want to video rapid sports motions, tennis strokes, golf swings, etc. for stop action frame-by-frame analysis, I'd suggest that you find one of the above Casio models used.
If you want to do entertaining high speed videos, where stop action analysis is not important, then the AUTO exposure control cameras that might have more Jello Effect distortions but record attractive HD may do well for your application.
Basic High Speed Video Considerations and Cameras
Casio Talk Forum
GoPro comparison discussion
GoPro on a tennis racket-
High Speed Videos with Casio FH100-