If you want bigger/ leaner arms focus more on your tricep training. I have seen plenty of guys & girls spend hours doing countless bicep exercises. The simple fact that the tricep is made up of 3 muscles ( the bicep 2) , will tell you that training this harder will equate to larger arms.
These 3 exercises have been part of my training for may years as I consider these my go to exercises. I personally perform sets of each with a rep range of around 8 – 10 with the exception of rope pushdowns as I like to go higher , around 12 – 15 reps.
Rope Tricep Pushdown
Attach a rope attachment to a high pulley and grab with a neutral grip (palms facing each other). Standing upright with the torso straight and a very small inclination forward, bring the upper arms close to your body and perpendicular to the floor. The forearms should be pointing up towards the pulley as they hold the rope with the palms facing each other. This is your starting position.
Using the triceps, bring the rope down as you bring each side of the rope to the side of your thighs. At the end of the movement the arms are fully extended and perpendicular to the floor. The upper arms should always remain stationary next to your torso and only the forearms should move. Exhale as you perform this movement. After holding for a second, at the contracted position, bring the rope slowly up to the starting point. Breathe in as you perform this step.
Using a close grip, lift the EZ bar and hold it with your elbows in as you lie on the bench. Your arms should be perpendicular to the floor. This will be your starting position.
Keeping the upper arms stationary, lower the bar by allowing the elbows to flex. Inhale as you perform this portion of the movement. Pause once the bar is directly above the forehead. Lift the bar back to the starting position by extending the elbow and exhaling.
Close Grip Bench Press
Lie back on a flat bench. Using a close grip (around shoulder width), lift the bar from the rack and hold it straight over you with your arms locked. This will be your starting position. As you breathe in, come down slowly until you feel the bar on your middle chest. Make sure that – as opposed to a regular bench press – you keep the elbows close to the torso at all times in order to maximize triceps involvement.
After a second pause, bring the bar back to the starting position as you breathe out and push the bar using your triceps muscles. Lock your arms in the contracted position, hold for a second and then start coming down slowly again. When you are done, place the bar back in the rack.