Plank on a Stability Ball

This video teaches how to perform a proper plank on a stability ball for added challenge. Here's a link to order your own stability ball: https://www.amazon.com/gp/product/B0187LW0A6?ie=UTF8&tag=kimmerkelfitn-20&camp=1789&linkCode=xm2&creativeASIN=B0187LW0A6