I ve been taking brazilian jiujitsu for just over a year now and....?

i still use strength. my question is this;after a bit of insight to my thinking.... i know helio gracie was the weakest and slowest brother etc etc and that he formed his own variations to deal with this. he became unbeatable for his brothers i think. im wondering did his brothers only do regular jiu jitsu because where i am practicing bjj with other bjj people i have to really use strength to get some submissions as the other person is aware of the same moves as me. So basically if 2 bjj guys are rolling how do they not need to out muscle the other to get the submission?