Maud knows Hokuto Shinken. Rarity is already dead.

@Professor Genki
 
Applejack can casually smash timberwolves into splinters in later seasons. They’re not very consistent, given that relative power and “physics” are bent for the sake of a cartoon. In the case of Rarity KO’ing the Wonderbolts, that is ludicrously out of proportion to force Rainbow Dash to have to save her.

@Tirimsil  
I have better examples but chose the one I thought best. IMO, I’d revised that list as:
 

@Professor Genki
 
… and she doesn’t use kicks to mine. True, this does not discount her strength because if she was at least as strong as Applejack she would cause a cave-in and kill herself ergo she would willfully refrain, but it’s silly to act like Rarity’s geopathy has anything to do with her leg strength when she does it purely with magic.
 
You would have had a much better example by citing the few times Rarity has bowled Applejack over or smacked her offscreen (though, as I recall, Applejack was never on guard for an attack in any of these circumstances, and Pinkie Pie has both of them beat in the bootypocalypse department.)
 
The likely order of Kick Power among the Element-Bearers is:
 

Headcanon, supported by show facts, that Rarity has the strongest kicks out of the mane 6
 
Yes, AJ is strong too. But in comparison, AJ farms, Rarity mines for gems. Rock is harder than trees, Maud understands that

@Background Pony #BB7E
 
Maud would make for an excellent CP9 member XD

“Tekkai.”  
“That was a strong attack… You almost broke through my Tekkai…”

@VladimirMacHolzraum
 
That’d make for good headcanon.

Muda da. (It’s useless.)

maud is Krypton ponies?

Maud: “…Ow….That Hurt….”

@Background Pony #A615  
Maybe her rock-related strength derives from earth pony magic based on her special talent.

@Blissey1  
Theorized by some? Really? That just sounds incredibly stupid. Rocks are heavy and huge rocks are really heavy and they were perfect things to show that Maud is strong as hell. How could anyone come to a conclusion that her strength would only work with rocks?

@Background Pony #B168  
keep in mind, it’s entirely possible, and theorized by some, that maud’s super awesome earth pone powers only work on rocks. Since, ya know, we only ever saw her doing stuff to rocks.
 
it’s up for debate if she could pull the same stunts on non-rock objects.

@Background Pony Number 17  
Let’s see. Rarity kicking unsuspecting Applejack who is completely fine just a few moments later.  
Rarity kicking a manticore which just made it angry. (and Rarity running away after that)  
Pushing Twilight over with her butt… really?  
Slapping a changeling. A creature that doesn’t seem to a match for anypony alone but needs a huge swarm of others like it to overwhelm enemies.
 
I’m sorry but if that gif is supposed show Rarity’s best, it’s just sad.
 
Maud punches huge rocks to pieces and tosses giant boulders to the horizon.
 
It wouldn’t be a good show. It wouldn’t be even an obstacle. It would be a slaughter.

Maud: ‘Going to need some milk, apples, hrm, what else do i need while i’m out?’

@Background Pony #A615  
 
Don’t diss Rarity’s fighting skills. Granted, my money’s on Maud, but Rarity would make a good show of it.

@Background Pony #A615  
What a mere rock can do against a gemstone?

Let me guess, they are fighting over Tom.

Maud versus Rarity? That’s like a real tank versus a plastic toy car.

Armament Haki.