Maintaining strength - the best way?

I find Xi Gung/Shibashi better for flexibility and balance.
Not sure what helps with strength and what sort you are looking for.

Walking as often and as far as you can is so good for you and if you add a dozen squats and worktop press ups every time you wait for the kettle to boil it’s an easy daily workout which costs nowt!

My daughter-in-law would say kettle bells. And that's what I think I should be doing given the evidence.

Lost my post!

Yoga is good, classes vary and some are more intense than others. It is strengthening as well as calming.
I've tried various types of exercise over the years but can't get down on the floor now and that is limiting as I definitely can't leap around any more either.

During lockdowns I did Qigong, slow but supposed to be effective.
Some people I know swear by Tai Chi.

I go to the gym three times a week use resistance machines and also walk on an incline on the treadmill.Use the rowing machine for a few minutes…(Because I find it so difficult, But it is a very good workout for the whole body)