From this alone, Ludwig understood how rich a Larger world is. If he had to guess, then probably all adults in the Upper World were body strengtheners and the talented mortals could even reach the qi refining realm.
One has to understand that mortals are those with no spiritual roots, the natural spiritual power is just so high that their body has a higher concentration, enabling them to take in a bit of it to advance, even though that shouldn't be allowed technically.
This was what made Ludwig so fascinated – a world where even the weakest human could carry hundreds of weights and slap steel flat… then again, the steel here is stronger since it also absorbs spiritual power and probably only the lowest of steels doesn't contain any spiritual power, a piece of iron on that level might as well be called a rock.