On average a skin fold test has most athletes coming in around the 4-5% mark in Very good contest shape, but alot of guys are around 5-7% and rely on dehydration to acheive a tighter look , I myself could regulary get to a 3.5% reading for a show and they classed me as one of the best all time lean contenders out there , getting lean was never a problem , getting big was the hard bit !!! At 3.5% you should have toataly stirrated glutes, back and lumber(these are the last place for body fat to desperse from for a guy) Other than the skin fold test which does have its inconsistancy especialy if it is not done by the same individual every time , and is only used as a guide line for calorie calculation, the only true way to get a true BF% reading is by useing 'Water dissplacement " calculation , and I doubt many would go to that trouble !! Would flex have been O.O% no , it is impossible, at has best i would have had flex at 4.5 % through skin fold readings , at 3.5% readings that i used to acheive my immune system was badly compromised and it always took a good month or two to get back to feeling healthy again !!!!!
