As an adder to what holds you back...I've never had any instruction, What I do (archery~wise)I learned on my own. I've never had anyone fine tune me...and Lord knows I don't have the stones to post an evaluate my from thread!
As a golfer I've had pro's tweak me to "look" better...after losing a season here and there working through the changes,to lesser success,I've adapted a happy medium, that works best for me. It may not be taught..but no ones urging Jim Furyk to change anymore either.
