A common mistake with standing barbell or EZ Bar curls is what I refer to as “elbow push.”  Elbow push occurs if you lift or push your elbows upward as you complete the curling motion during what should be peak contraction of the biceps.  Moving the elbows upward shifts resistance from your biceps to your shoulders and defeats the entire purpose of doing curls.   In other words, you can’t build mass and shape in your biceps by using your shoulders to complete your curling motion.   

For maximum efficiency during your biceps training you must make sure that they do the work during your standing curl workouts.  To ensure peak contraction of your biceps at the top of the curling movement, keep your elbows at your sides throughout this exercise.  Otherwise, poor training technique – as exemplified by “elbow push” – will delay your progress and ultimately frustrate your training efforts.