Pilates
"Pilates develops the body uniformly, corrects wrong postures, restores physical vitality, invigorates the mind and elevates the spirit." Joseph Pilates
Pilates is a safe, low impact method of exercise which works on developing core strength and stability, stretching and toning muscles and improving posture. It can help improve mobility and flexibility of the spine, and keep joints healthy.

Pilates is similar in some respects to yoga, but with some differences. See here For one view on pilates vs yoga
Exercises can be adapted to suit individuals’ needs, so you always work to your own level of comfort and ability.
You can find out more about pilates at the Pilates foundation
There are lots of pilates videos on the internet too. Try Pilates Essentials to start