I've had others mention walking in water. I've not tried it, not yet, but it make sense. Walking in water would provide forward-motion resistence without the pound, pound, pounding punishment other exercises give the knees. Thanks for mentioning this, @holdrege. –Ray (@ray666)

Good to know. I did a lot of walking in water pre'pandemic but haven´t gone back. That´s something I can look into. The pool I used to go to which was very close-by no longer offers this possibility so I´ll have to go to a new pool that I´ve never been to before that is twice as far away. It just hasn´t happened. Perhaps this is the time to correct that! Thank you for the suggestion.