i think i'm gonna take up 20 minute jump rope sessions with some kettlebell excercises on my off days
Jumping rope will really work on your knees and your feet as you age. As a word of well intentioned advice to you younger guys - save yourself some grief later in life and try to go for not jarring type of aerobics - I do mine these days via my concept 2 rower - I used to jump rope a lot- first thing to go were my feet and then my knees - Im a lot better now after being off the rope for several years, but I know the damage is still there.
If youre persistant it, rowing will give you a lean muscular build coupled with a weight program - great lat and upper body development and stamina. Im pushing 55 and have a better body than the majority of guys half my age.