Most multi-joint upper-body pulling exercises predominantly train the biceps in the mid to shortened-range position.
To increase your strength, do exercises like preacher curls and what I call "face-away cable curls" shown here.
related posts
Fight Muscle
An interview with Coach Scott Sonnon
Tip: The 10-10-10 Treadmill Sprint Workout
Want a bigger engine? Do metcon with progressive overload. This is tough and it only gets tougher... but so will you. Take a look.
Tip: Two Quad-Building Bike Workouts
Some of the biggest quads in sport are built on bicycles. Here's are two leg blasting bike challenges you can do in the gym.
I, Bodybuilder 1 - Shoulders - Saturday
Build muscle as fast as humanly possible — week after week — until you see a body in the mirror that you barely recognize.