I usually just stay active like you did...in the yard choppin', whippin', tossin', haulin', rakin', shovelin' and throwin', but repetitive motions do lead to issues.
Five to ten years ago, I weight trained with a trainer for a year or two, twice a week. Interesting program consisted of 8-12 second reps, both up and down, with reduced weight. Look up "InForm Fitness/Power of Ten".
Used to ride the hell out of a ten-speed, had legs like a horse at one time.
Done the competitive motocross/supercross thing for a year - second most fit athletes in the world, soccer is first. Trophies were won, so I musta gotten something out of it. Otherwise, a lifetime of random riding just for fun has always been a fitness test.
I'm interested in doing the Extreme Seal Experience but have no intentions of showing up in my current condition. Lotsa runnin' and pull-ups to get under my belt first. I want to, at least, pass the current BUD/S physical screening test. I'm 54.
I was runnin' 6:12 mile times during my enlistment whenever the fitness tests came around. I hate runnin' for fitness...absolutely despise it.
I swim like a fish and that's my favorite exercise. Plenty of cardio, then back it up with some mean calisthenics. Unfortunately, I have no lap pool access, but there is a river right down the road.
I've yet to start that program but it's the one I'll use next. Running will be a part of it.
All the yard work has consisted of clearing 2 acres of underbrush and deadfall, by hand. The goal is to turn the 1/4 mile perimeter into a fitness trail. The property is sloped and proves to be an ass-kicker even when not exercising.
Quite frequently, 16oz curls has been my mainstay. I don't mess with those wimpy 12oz curls.