https://health.clevelandclinic.org/piriformis-syndrome-stretches-exercises
This is a very good informative article about piriformis syndrome containing several video stretches that would be easy to learn and choose from for an older person. I know, because I am one--78 years old. I have to do at least three of these stretches daily to avoid pain. In my case, I suspect my extensive sitting is at fault--and not PMR. But it's hard to tell, isn't it? I also have some spine issues aggravating my sciatica. Most of these stretches will help with that, too. I also recently invested in a "walking pad". After research, I chose one that is wonderful for rehab and for seniors.