I'm not an expert at this by any means, but without seeing your hand vs your span, I am guessing you have an incorrect fit with the span being too long. I recently was having a problem with the first joint of my middle finger. I discussed this with "pin-chaser" and we shortened the span 1/2" and went from 1/8 reverse on thumb to 5/16 forward and fingers were moved from 0 forward/reverse ot 1/2" forward. Also changed from the lift side of finger grips to oval grips.
No more finger pain, no more squeezing the ball, no more sore arm, can bowl more games with out arm or shoulder getting tired, no more sore shoulder, plus higher scores, and better accuracy at hitting my target.....and the ball fits like a custom made glove and feels lighter.
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Lane 1 - The Bowlers CompanyNothing hits as hard as an
Uranium