Maki has a pituitary disorder.
Despite Maki being a six-foot beefy schoolgirl
, we see her as a younger and much smaller gymnast in flashbacks. Obviously, she was disallowed from competing for health reasons, and also for the liability of her size impacting her performance. This extends to Maki's references to "having a dampener on her feelings", implying she's physiologically depressed and uses adrenaline to self-medicate.