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
Prime, Build, Strengthen: The 3-Phase Size Plan
You can't keep adding load and volume all year round. So here's how to rotate through muscle-building methods to build your best body ever.
21st Century Core Training 1
Everything you need to know to develop a strong, powerful core.
5 Critical Exercises for Athletes
Muscle imbalances are weaknesses. Weaknesses cause injuries. Injuries suck. Fix the problem. Here's how.
Top 5 STRICT Bodyweight Exercises
Do you do them all? Master all these moves to become an all-around more awesome human.