Amelia Boone, age 30, has crawled through barbed wire, swum in icy rivers, received electric shocks and hauled rocks up mountains: It’s how she likes to spend her vacations. When she’s not working 10-to-12-hour days as a corporate restructuring associate in the Chicago office of Skadden, Arps, Slate, Meagher & Flom, Boone is defending her status as one of the top U.S. female contenders in the fast-growing sport of obstacle racing.

Extreme endurance contests such as Tough Mudder, Spartan Race and Death Race have drawn increasing numbers of competitors in recent years with diabolically difficult challenges. The Tough Mudder race, for instance, includes “electroshock therapy,” in which participants sprint through a field of live wires. In 2011 Boone and three Skadden colleagues entered the World’s Toughest Mudder purely for fun. Boone placed second for women and finished 11th place overall. Unlike her coworkers, she was hooked. Since then, she has run 15 additional obstacle races, placing among the top three female finishers in 14 of them. (She dropped out of the 2013 Winter Death Race after experiencing early-stage frostbite from hauling beams out of a Vermont river in February.)