Originally Posted by Relinquis
In another reply, I mentioned that if you have a video of a serve and it does not show the ball impact, to forget about that video. This instructional video has the racket head at impact entirely out of the frame, a red flag? Also, you cannot see what is going on unless the video is high speed video, say, about, 240 fps more or less.
Instructional videos on the serve that don't use high speed video and very fast shutter speeds (= outdoors in direct sunlight) are likely to be misleading.
In my opinion, it is very misleading, when he demonstrates statically how the wrist brushes across on the kick serve, regarding joint motions which are very complex around impact. I do not understand it in detail yet, but the arm is rotating around its axis at impact from ISR - unlike in the static demonstration starting at 4:08
- and that will allow the wrist to move more freely through the motion at impact. If you held your arm from rotating on a serve as shown, it might be very stressful to the wrist and otherwise and might risk injury.
Here is a video that I believe is of a kick serve but I'm not sure.
How can this compound motion at impact be described is a few words related to just one joint like the wrist?