As we are all unique, we should adhere to activities that strengthen without causing undo stress on our weak/fragile tissues. For me, walking has been instrumental, it connects me with nature, is great for cardiovascular health and promotes muscle tone resulting in less stress on my tendons and ligaments. When I was younger I used weights, ran, golfed, bowled, danced etc. but as I've aged those activities seem to cause injuries that never seem to heal.