A 7 mph increase by simply cupping the wrist at the beginning of the pitch?Here is another post about a bent wrist and the OP stated a 5-7 mph increase in speed with a bent wrist. It sounds like he started the bent wrist at wind up and all the way through.
My guess is prior to this his DD was releasing with "extension" and then when he tried the bent wrist she found flexion. Again, just a guess...
Recently I watched a very dominating pitcher at the Ohio State Championships win the title with a windup where she started with the wrist tucked or bent with the ball prior to starting the windup. When the ball was overhead she extended the wrist and completed the pitch. My 12 yr old daughter...www.discussfastpitch.com
Some girls are gonna be throwing 75mph after they hear this.