Flick Strength
Mechanism / Why It Happens
The rotation is created by flicking down on the nose, but too much force can drive the nose into the ground.
To rotate the board, you need to apply a force that pushes the nose diagonally downward. This force makes the board rotate forward, but at the same time, it reduces the force carrying the board upward. If you push the nose down too strongly by extending the entire leg, you can cancel out the upward force acting on the board's center of mass and pull the board downward, causing the nose to hit the ground.

What to Do
The key is to keep the force pushing down on the nose brief and compact.
To allow the board to keep rising even after the front-foot flick, the force applied to the nose dur