Most of the time when doing these the handle pops out of my hand. What is going on? Thanks

sounds like you may be cutting to far away from the boat and this is creating to much line tension and you are popping the handle? id either say dont cut so hard away from the boat or hit a pull up bar. i started doing pull ups, sit ups and push ups a couple of years ago (for an academy) and noticed it helped my riding alot.

When you say cutting too far away from boat is this while initiating the flip or setting up to edge in. I am actually posting for my daughter who is very conditioned.

my thinking was that she was initiating the flip with the board pointed to far away from the boat. when i learned them edged away more than just a normal wake jump. i did this in order to speed up the rotation, which it does but also makes the line very tight. tell her to keep her elbow bent too when starting the flip this will allow a little error room and she can let her arm out away from her body to control the line tension