How to have bigger biceps : 13 - Fully stretch the arm each time :

👉 12 - Focus on brachial exercises

13 - Fully stretch the arm each time :

If the length of the biceps, the length from the elbow to the shoulder, corresponds to the one you are looking for, you will have to focus on the beginning of each recovery and not on the moment when 

the movement is at its peak, which allows to develop the muscle. Make more effort to lift the weight and slowly rest it at the beginning and end of the exercises. One of the best ways to develop the biceps is to resist as long as possible to inertia when you fully stretch your arm

👉 14 - Opt for a tighter grip.