When it comes to training the biceps, simply doing more sets and reps won't cut it. The problem? Most lifters are hitting the SAME parts of the biceps over and over again while completely leaving out – or at least under-stimulating – other parts. You need to hit both the long and short head of the biceps brachii (as well as the brachialis). Here's an exercise for the often neglected short head:
Spider Curl with Slow Negatives and Iso Holds
Spider curls – where you lean over an incline bench and let the arms hang straight down – target the short head of the biceps. The big advantage of spider curls over preacher curls is the constant tension, especially at the top portion of the movement.
The slower negatives allow more time under tension during the eccentric or lowering phase, where we can handle more load. This allows you to work at a higher intensity, and higher intensity means greater stress which means greater adaptation.
Here's an additional twist: use a fat grip. One of the benefits of thick-bar training is that thicker handles stimulate much more muscle activation in the hands, forearms, upper arms, and even the whole upper body. More muscle activation means much bigger muscle and strength gains.