I've had the same problem. I find that hammer curls with heavy ass weight, even if you have to cheat a little bit helps, along with preature curls and cable curls. It's important not to cheat with the cable curls tho, a lot of guys do it to just get it done... full extensions and dont bend ur wrist...if this means less weight then so be it... it pays off tho! goodluck bro!