Thumbing the ball is often caused when the bowler starts turning the hand early. There are lots of visuals that work to keep the hand behind the ball longer, but the one I like best involves the elbow position.
If you keep your elbow "inside" longer the hand has to follow. Try to not turn the ball until you're into your slide step, or just slightly before. With the hand in the proper position the ball can leave the thumb first and then the fingers can apply the revs and rotation.
John Jowdy (I believe) says to keep your ring finger going towards your target longer, which also helps you to quit turning the ball too soon. Good luck.
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Lane Carter, Strike Zone Pro Shops - Salt Lake City, Utah
Brunswick Pro Shop Staff
www.brunswickbowling.comThe opinions expressed are solely those of the writer and not of Brunswick Corporation.