One study investigated the relationship between flight muscle structure and the flies' flight capacity: as the number of mitochondria increased, myofibril diameter increased, and sarcomere length decreased, the researchers found the fly's flight capacity to be maximized.
The research explored how a fly's muscular structure influences its ability to fly: as the number of energy-producing components (mitochondria) increased, the size of muscle fibers (myofibrils) expanded and the distance between muscle units (sarcomeres) decreased, ultimately leading to optimal flight capabilities.