In Charm, when Mirabel realizes that the candle’s magic is losing strength, her family members begin to demonstrate that her powers are failing. Among them, Luisa is the first to have problems with her super strength, as, right after her musical number, “I’m Nervous”, she confesses to losing connection with her ability.
While this is not explained in the film, a fan theory suggests that Luisa’s difficulties relate to the theme of Charm. Over the course of the animation, Madrigals must learn to value themselves for themselves, not just their gifts. As the character clearly questions his place in the family without his powers, he becomes the most fragile on a personal level.
In response to this, Luisa’s ability begins to weaken in parallel with the candle flame that gives the family magic. When talking to Mirabel, Julieta and Agustín’s middle sister confesses that she felt weak during her cousin Antonio’s party, at the same time that the protagonist saw cracks forming in the Casita. Soon after, the light on the magic door to her room starts blinking.
In addition, Luisa begins to struggle to lift heavy objects that were once light for her, such as a large potted plant and the family piano. This is relevant because while all Madrigals work to help their community, Mirabel’s sister’s super strength is the most in demand among the villagers.
So, because of this need to constantly work to establish her worth, Luisa never rests. The pressure of always doing menial work may have made her resent her powers, making her the most susceptible to the weakening of the Madrigal’s magic.
Charm is available on Disney+.