After Sweetie Belle defeated both Scootaloo and Apple Bloom, she felt like she could take on anyone. So, she challenged both of them at once, not realizing that was exactly what they wanted. The girls took advantage of her overconfidence and easily overpowered Sweetie Belle. Then, they gave her a taste of her own medicine, with Scootaloo placing her foot on her face and Apple Bloom stepping on Sweetie’s stomach.
Scootaloo: “Not so tough now, are ya?”
Apple Bloom: “Maybe that will teach ya a lesson.”
Sweetie’s initial response were painful moans until she passed out, letting the girl play with her uncouncious body. This was a rough lesson to learn - never underestimate your opponent and all of the Cutie Mark Crusaders benefited from it.
(If you liked this, I might make more Equestria Girls pics in the future, maybe not just trampling poses, even though they are my favorite ^^”)