Why is this exercise performed from a kneeling position?

Kneeling reduces the ability to use your legs or hips for momentum, ensuring the brachialis performs the majority of the work.

How does this differ from a standard hammer curl?

The seated or kneeling angle combined with the thigh support provides better isolation and prevents the recruitment of stabilizing muscles.

Can I perform this exercise standing?

While possible, standing makes it harder to stabilize the elbow against the leg, which is the primary benefit of the jalon caballero variation.

Jalon Caballero Unilateral Guide | Build the Brachialis

Learn how to master the jalon caballero unilateral curl safely. Improve arm thickness and brachialis definition with our expert step-by-step instructions.

How to Perform

Assume a half-kneeling position with your right knee on the floor and your left foot planted firmly in front of you.
Hold a dumbbell in your right hand using a neutral grip with your palm facing inward toward your body.
Rest your right elbow against the inner part of your right thigh to create a stable anchor point for the movement.
Curl the dumbbell upward toward your shoulder while keeping your wrist straight and avoiding any torso rotation.
Squeeze the muscle at the top of the contraction for one second to maximize tension.
Lower the dumbbell slowly back to the starting position until your arm is fully extended.
Complete the set on one side before switching your kneeling stance and repeating with the opposite arm.

Common Mistakes

Using momentum or swinging the torso to lift the weight.
Allowing the elbow to drift away from the thigh support.
Flexing the wrist excessively at the top of the movement.
Shortening the range of motion by not fully extending the arm.

Muscles Worked

Primary movers

Brachialis

Stabilizers

Biceps Brachii
Brachioradialis
Forearms

Related Guides

Air Pushdown — Arms
Alternating Biceps Curls With Dumbbell — Arms
Alternating dumbbell hammer curl — Arms

Brachialis · Arms