Originally posted by Q99👆 excellent post.
Bigger build for one thing, heavy muscle training for another. One thing to remember is when he was young and didn't have his powers/only had them at drastically reduced levels, he was still a farm boy who'd carry around hay bails and such so by the time his powers kicked in he had a really strong base to work with.And, fighting high level bricks and such for many years, he's got exercise that's tough even on kryptonian muscles too, he has had to push himself at his limits on many occasions and thus is better at pushing himself to the edge of Kryptonian abilities than PG or SG, being more used to digging deep he can probably do it on purpose easier. Both his solar-absorbtion powers and muscles have been given more workouts than any other hero I can think of.
Kara's got the build of a fairly athletic teenager, Karen's significantly more buff and definitely closer to Clark's strength, she's also worked out a lot, but she's not as big, and doesn't have as much practice pushing herself to her max. So she's definitely closer to Superman in strength than SG is, but still there's a difference there.
Plus, Superman and Wonder Woman are part of the 'Trinity,' as discussed in the 52 issue series of the same name, and play important roles in the world which can affect power. There's sort of a chicken-and-the-egg "Does being part of the Trinity make Clark and Diana a bit stronger than their close rivals, or does being two of the strongest heroes make them part of the trinity?", but whichever the case there's some metaphysics of DC involved on why those two have an edge on others.
Btw, sometimes when I talk about the different strengths/powers of characters I'm referring to all-around combat power more than pure muscle. PG is pretty well up there in muscle, she compares herself to Captain Marvel (another near-Superman type), and the WW fight also showed she was strong and a half, but in terms of 'Power' Wonder Woman is higher due to other powers, skill with them, and approach (PG's pretty strait forward- and understandably, she didn't even have access to heat vision for many many years, and taking on foes strength to strength works well for her, so she doesn't have quite the finesse Clark or Diana do).
But i still don't like Diana.