What is an OCR? Do you want to challenge your strength, skills, endurance, speed, and even your mental strength in a lively and exciting way? Then OCR is for you. But what is OCR? OCR is short for Obstacle Course Racing, also known as Mud Run and Adventure Racing. It is a sport that challenges you to defeat your opponents while also conquering a set of obstacles. This is an out-of-the-gym activity where you will run miles on dirt paths, in muddy water, and past semi-insane obstacles.