Complex sentence: Some sports, such as athletics, divide athletes by both the category and severity of their disabilities, other sports, for example swimming, group competitors from different categories together, the only separation being based on the severity of the disabiliy.
Split into simpler sentences: Some sports, such as athletics, athletes are divided by both the category and severity of their disabilities. Other sports, for example swimming, group competitors from different categories together, the only separation being based on the severity of the disabiliy.