1. https://www.youtube.com/watch?v=kgR5Zw71kEs&ab_channel=MatthewSorensen
2.Fill it with… water! as in the following instagram post!

As you push your leg into the yoga ball, it becomes more instable, but if too much instability, lessen the pressure.. Keep applying this principle.
“stop making your training into a circus act on bosu balls. Unstable training doesn’t have to be on unstable surfaces. What you should do to improve coordination and stability”
