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
Tip: Do Hamstring Curls Before Squats
Pre-pumped hamstrings will make your squat feel more comfortable and stable.
Tip: Stop Training Only Half of Your Hamstrings
Are you missing a big portion of your hammies? You are if you're neglecting to do these two things.
Bench, Squat and Deadlift: How Often?
Most people train the big lifts once or twice per week. But the strongest people in the world use a much higher frequency. Here’s what you can learn from them.
Tip: The Most Important Key to Workout Consistency
Researchers have figured out how to stay consistent in the gym. Have you? Check this out.