Koa Hester knows all about jams – not the sweet kind that goes on toast, but rather those short matchups that are part of roller derby. Hester joined the Pixies, a junior league roller derby team in Spokane, when she was 10. She fell in love with the sport when she was 8 and watched her mother participate. “I wanted to be just like her,” said the 18-year-old daughter of Clara Hester, a seamstress, and Kaleb Hester, a truck driver. The family lives in Spirit Lake, Idaho, where she is about to graduate from Timberlake High School.