A perfectly adequate camera with high speed video capability and MANUAL exposure control to minimize motion blur
for stroke analysis is the Casio FH100. Unfortunately, since 2010 Casio no longer manufactures this camera. Some new left-over stock from Japan appear on E*bay, $380. Used FH100 cameras are also available. [In HD the FH100 records to only a maximum 4 Gb video file size even with a large SD card installed so that the camera must be restarted to record long match times.]
To my knowledge all other currently available affordable high speed video cameras are AUTO exposure control. Too much motion blur will result.
See also Kinovea for basic high speed video camera considerations.
If I could find HD and high speed video together in an affordable camera I'd buy in a second, good luck. If you wish to do high speed video for stroke analysis research also Jello Effect distortions for any camera that you are considering.
You can get cameras that do 60p - 60 frames per second progressive - that will AUTO select very fast shutter speeds in bright direct sunlight. 60p with small motion blur can be very useful even for some slower stroke analysis. Forget the serve.
Sorry that I don't have any experience with the Hero..........