in most casess champion bodybuilders have fantastic genetics,that makes it easier for them to build muscles than the average person with normal genetics,but sometimes a champ or an advanced bodybuilder might have poor genetics in a certin muscle,this creates a problem for them becouse they expect that muscles to respond to the same type of trainning that a muscles with good genetics respond too but it doesn't,this confuse them,unfortunetly it's difficult to approcsh them to give them advice and they are to proud to ask for it,the results,there strong muscles keep on improving and their weak muscles stay the same.what a shame.