Tall Kneeling Frontal Plane Stability with Balance Board
Here is Physio Answers Contributor Dr. Aaron Swanson demonstrating an exercise for Frontal Plane Stability using a resistance band and balance board.
As always, you should be practicing at the edge of your ability. If this is too difficult, painful, or you are wobbling all over the place, you need to regress or try another exercise. This should be challenging, but not overly so.