CORRECTION: I looked at the slow motion of your first two videos again and now see that your upper arm looks in line with the line between your shoulders. Your elbow has a considerable angle in it.......
Originally Posted by TomT
Ok, but I think I have a pretty good idea what to do to improve both the velocity and spin of my serve. It's just that my current physical capabilities are hampering the realization of that.
Have you seen the Todd Ellenbecker video on the shoulder, serving and minimizing impingement risk? The angle between the line between your shoulders and your upper arm might be too large in my opinion.
Check out the Ellenbecker video. Search in the TW Health & Fitness forum: Ellenbecker + shoulder + impingement.
I wish I had your slice serve....