my 4arms explode when i lift...it kinda sucks because i hav smaller bi's in my opinion for my size....what i find really hits the 4arms are a machine at my gym for grip...i put 1 45 on it...and go till failure with each hand...just squeezing,hold it for 3 seconds...then i grab the 100 db's and hold on to them for a bit.another one is hold a bar behind u with some weight on it..and roll ur wrists up...it kills if u go to failure...i do my 4arms once a week...but u can do them twice a week i read somewhere...hit them with ur calves