have done my fair share of inj. looked it up of were u are suppose to inj. and i am close but differ seams that i want and think u should go into the thickest part of the muscle not always the case when you look at the diagram or even vid. so never had a prob. ok the question is a quad site i have done inner and outter but were i really think I should go is that thick meat right up front. as i said i move around alot and sometimes hurts more than otther times but no big deal