Using the barbell to curl is not just a bicep exercise.
i would never recommend to anyone to use an ezy-curl bar, if you want healthy elbows and shoulders supinate the hand fully.
the main function of the bicep is to lift the arm over your head.
the bicep curl is a good, very good exercise but it does not train the bicep fully, to prove this.
make a fist supinate the hand, flex the bicep, now while flexed lift your arm and draw your fist down behind you back and hold and flex your bicep hard for one minute, then let me know what you feel.