Though she calls herself an “art kid” at her core, Christina Jefferson is no stranger to contact sports. Recently hired by the San Francisco 49ers to lead diversity and inclusion efforts inside the football organization — a newly created position — Jefferson has a long history with a quite different , yet still bruising, athletic pursuit: roller derby. In roller derby, players in full pads and helmets race around an oval track in roller skates, jostling and jockeying for lanes, blocking and body checking each other along the way. The sport traces its roots to the 1930s but was revitalized on television in the 1960s with the help of Jewish Bay Area showman Jerry Seltzer. In a 2017 interview, Seltzer called the game a “symbol of women’s empowerment.”