Obstacle-course races require you to refine your skills in numerous areas such as running, climbing, crawling, swimming, and jumping. Robert Killian, a former Green Beret, won the Spartan Race World Championship in 2015 and has detailed what you need to do to train for a race. Killian prefers to do functional fitness where you use minimal equipment and focus more on doing bodyweight exercises. For a warmup he recommends a 15-minute run followed by pullups and dynamic stretching to prevent injury. He also discusses doing burpees, knee raises, planks, box step-ups, and sandbag carries.