That is not the same though. That kind of work would continue for hours even all day. And that day after day. Different way of developing muscles, I would think.
There is a lot of lifting in farm work, though, and lifting is lifting. I garden for a living and am constantly lifting and hauling large sacks of fertilizer, barrels of compost, large shrubs and heavy equipment, loading and unloading the truck, pitching forksful of bark mulch into wheelbarrows, and other such work. I am quite muscular as a result. I also do a lot of tree/shrub pruning with saws that work on the pull stroke, and with bypass pruners that develop a vise-like grip. And, I split and toss firewood, which is a great workout!
Interestingly, I try to minimize the use of muscle in my work, relying a lot on frame and structure to do the real heavy lifting. Conventional muscle plays a role in the initial lift, but when I'm carrying heavy items, it's my frame that is bearing the load, not muscle, which is why I can work long days without tiring, even though I am in my mid-50s.
If I correctly recall some of Ueshiba's history, didn't he do some heavy-duty farming, perhaps even intentionally to add to his physical strength?