How do you define arrow length?
 

My Easton Axis arrows are 28 1/8 inches long without knock. With knock form tip of knock to end of shaft it measures 28 3/4 inch, but from where the string actually contacts knock it is 28 1/2 inches. So the question is when figuring out kinetic energy how do you determine the length?

RE: How do you define arrow length?
 

from the groove of the nock to the end of insert.