Straight bar curls with a shoulder width grip is the single most effective biceps mass builder there is. However, you need to understand why.
Straight bar curls are the most effective for building biceps primarily because they allow for the greatest amount of overload to be used. Overload is directly related to muscle growth. More overload equals more growth. Also, straight bar curls are very efficient. They allow for the most overload and muscle fiber stimulation in the least amount of time. And finally, straight bar curls place maximum overload on the entire biceps muscle – both the inner and outer biceps.
Straight bar curls are such an effective biceps movement that you could easily get away with just doing them as your only biceps movement.
