I have hypermobility syndrome (as a variant of EDS), and I need an exercise(or exercises) to strengthen my sacrum that do not require dynamic movements. It is not uncommon for me to have joints slip out of place while moving, regardless of strength level. So the trick is to find something that allows for a certain amount of muscular development to minimize the freedom of movement in my lower back – without causing undue movement in the process.

Any suggestions would be welcome.