Dumbbell One Arm Concetration Curl (on stability ball)

How to do the Dumbbell One Arm Concetration Curl (on stability ball)

1. 1Sit on the stability ball with your feet planted wide and flat on the floor for a stable base, holding a dumbbell in one hand.
2. 2Lean forward slightly from the hips and brace the back of your working upper arm against the inside of your thigh, just above the knee.
3. 3Let the dumbbell hang straight down with your arm fully extended and your palm facing away from your leg.
4. 4Curl the dumbbell upward by flexing the elbow, keeping your upper arm pinned to your thigh throughout the movement.
5. 5Squeeze the muscle hard at the top, bringing the dumbbell up toward your shoulder without letting your elbow drift forward.
6. 6Lower the dumbbell slowly under control until your arm is fully extended again.
7. 7Complete all reps on one side, then switch the dumbbell to the other hand and repeat.

Form tips

• Brace your elbow firmly against your inner thigh so the upper arm stays fixed and the elbow does all the work.
• Use a slow, controlled lowering phase (2–3 seconds) to keep tension on the brachialis and biceps through the full range.
• Keep your torso and the ball steady — let only your forearm move, not your shoulder or trunk.
• Choose a weight you can curl strictly; the braced position rewards control over heavy loading.

Common mistakes

• Swinging the torso or rocking on the ball to hoist the weight, which shifts the load off the target muscle and can throw you off balance.
• Letting the elbow slide off the thigh, which lets the shoulder assist and removes the strict isolation that makes this curl effective.
• Cutting the range short by not fully extending at the bottom, which reduces the stretch and the work done by the brachialis.
• Dropping the dumbbell quickly on the way down, wasting the lowering phase where much of the muscle-building tension lives.

Frequently asked questions