She's going to defeat Lord Tirek much easier. here the story of how she got so strong

Twilight Sparkle was busying in her laboratory and creating potions
Twilight: alright just a little bit of this and a little bit of that and finish
She made a weird looking potion and drinks it.
Twilight: well down the hatch *she drinks it* hm, a bit bitter
She felt pain in her stomach
Twilight: my stomach hurts! What's happening to me?!
Her biceps grew big along with her legs
Twilight: What's going on with my body?!
Her pecs and abs popped out, leaving her all shredded
Twilight: I can't believe it, that potion made me so massive, look at my muscles!
She looks in the mirror and flex her pecs, biceps, and abs
Twilight: maybe I should create more potions for my friends.
The End