Your swing is very controlled so my first suggestion would have to be to loosen up and just let the ball fall.
By controlling your back swing so much you cause tension in your hand and arm which costs you speed and power.
I used to do the same thing but changed after getting help from a top coach over the summer.
My speed and revs went up about 10% after getting used to the adjustments that were made and I can bowl longer without getting even slightly tired now.
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It looks to me like your squeezing the ball and muscling it durning the upswing in your current video.  You may try pushing the ball to your left (so that at the end of the push away the bal is lined up w/ the center of your body.  Doing this should creat more of a inside/out loop in your swing (this is good) and should also make it easier to stop squeezing it but that your really going 2 have 2 work on.  

Secondly but slightly less importantly.  I think that your knees are 2 bent in your starting position a slight bend is all that is really needed then try to decend evenly (so that your head goes downward in a strait path as you go from your starting position to your finishing position).  I also think that your 2 bent / hunched over durning the begining of your approach you seem to finsh ok but you should probly try to change it so that your body bend (from the waist up) is either constant or goes slightly foward from your starting position to the ending position (rather than being upright at the end and bentover in the front)

dispite all this your game isn't bad but you may want 2 try these things out, if you have any other questions feel free to msg me.

Good luck and Good bowling