To perform an elbow circle plank on a yoga ball, start in a plank position with your forearms resting on the ball and your toes on the ground. Engage your core to maintain stability. Next, gently rotate your elbows in a circular motion, either clockwise or counterclockwise, while keeping the rest of your body still and maintaining proper plank form. Continue the circular motion for a set amount of repetitions or time, focusing on control and stability throughout the movement. This exercise challenges your core muscles and improves shoulder stability while also engaging your upper body and stabilizer muscles.