Dumbbell Russian Twist (On Stability Ball)

Setup

Upper back on the ball, knees bent at about 90°, hips level with the shoulders, one dumbbell held in both hands straight above the chest.

Steps

1. Turn the bell to one side, letting the ball roll under the shoulders.
2. Stop when the arms are level with the floor.
3. Bring the bell back over the chest and turn it to the other side.

Common mistakes

Hips sagging toward the floor: squeeze the glutes to hold the bridge. Bell dragging the arms past level: turn only as far as you can stop it. Feet sliding as you roll: set them wider.

Breathing

Exhale on each twist, inhale through the middle.