I was asked for suggestions of low-impact exercise. I have no certifications. These are things I like that work for me and some other people, too.
I have crooked kneecaps and was facing surgery and PT when my doc explained that I needed to strengthen the muscles in my thighs above my kneecaps. I learned that using the elliptical machines at the gym, particularly going backwards, is a super way to do that specifically and is a great low-impact workout for others’ needs as well.
For the same affliction, I could never bicycle much because the extreme bending and straightening caused awkward and constant popping of my kneecaps. BUT a recumbent (sitting with feet out in front of you) stationary bike worked just fine because the angle of movement was far less extreme.
Belly dance: It takes a little bit of luck to find a great instructor, and if you’re in a big city and have the means, definitely try out a handful of teachers. It can be as easy or as intensive as you want/need. My first teacher teaches at the local senior center in particular. It’s wonderful for most any body type and fitness level; I had a classmate who used it in her cancer recovery. LOTS of online instruction is available too, but the quality varies widely, so it will take a bit of searching/research.
Swimming: Dependent on your local resources, I suppose. I managed to get a $19/mo membership to all my city’s recreation centers, including the gyms, basketball and racquetball courts, and POOLS. I’m a newb to lap swimming and had the fortune of dating a lifeguard who loves to teach. I’m looking into lessons for adults to improve my movements, because swimming is hardly an intuitive sort of movement. Laps are not easy, and maybe just walking laps in the shallow end or water aerobics will provide a nice, cool workout.
Beyond that, I would have to do some research. A lot of people rave about yoga, but it just isn’t for me. Tai chi is a cool exercise, but the style just didn’t suit me. Let me know if you have any other questions.