A lack of hip mobility or hip stability can create problems throughout the kinetic chain and is a common cause of low back and knee problems. Roto discs are a nice portable tool that you can use to assess and improve hip function.
Here are some of the basic exercises that we start with and we use regularly in our Barre Bellas classes.
If you need some inexpensive roto discs, we have the ones used in this video in our online store. The price makes it possible to have enough for your whole class to participate!
https://www.youtube.com/watch?v=siirgXcZR_0