My Arm Path Adjustment Increased Velocity 

Some Hot Topic pants in the first clip.

How can I fix a long arm action like you did in the video?

Shorts are kinda long in the first clip haha

You'd be around 5mph faster if you rode your back thigh longer and didn't allow your knee to collapse over your toe. Watch Nolan and Jack Leiter. Notice how in the full wind up they position their back leg with a bend at the knee and from there they raise there front leg for the leg raise. This positions them for a longer/faster fall down the mound.