In a serve instructional video I would like to hear more about the stretch-shortening cycle. The 'kinetic chain' is more a sequence of steps where bigger-slower muscles stretch and move smaller and faster muscles. I don't get that from the 'momentum' discussion or much in the way of specific motions with checkpoints. If anyone can understand the final motion that leads to the high racket speed at impact please indicate the time on the video where it is explained. If I stop the swing motion with the racket in ball strike position at about 4:48, it's not the motion and body orientation used in real pro serves.
Greg, Have you taken videos of your serves from behind with your high speed video camera?
You should be able to compare your serve to ones like this and see the differences between 130 MPH serves and yours. There are other similar videos taken from behind.
At impact most pro serves have a straight arm that rotates extremely rapidly at the shoulder joint. The racket is also rising up rapidly and strikes the ball with an angle between the forearm and racket. This clearly shows in the videos taken from behind (and their thumbnails with ball impact). That picture is what you want for an initial assessment of your serve.
Before anyone tries new serving techniques, they should understand the Todd Ellenbecker video on the shoulder. Search TW Forum: Todd Ellenbecker video shoulder serve