While applications are typically optimized for traditional desktop interfaces using a keyboard and mouse, there are a variety of compelling reasons to consider alternative input mechanisms that require more physical exertion, including promoting fitness, preventing Repetitive Strain Injuries, and encouraging fun. We chose to explore physical interfaces based on foot motion and have built two applications with Step User Interfaces: StepMail and StepPhoto. Both support working with email and photos using the dance pad made popular by the Dance Dance Revolution (DDR) game. Results of a formative evaluation with ten participants suggest that the interactions are intuitive to learn, somewhat enjoyable, and cause participants to increase their level of exertion over sitting at a desk. Our evaluation also revealed design considerations for Step User Interfaces, including balancing effort across the body, avoiding needless exertion, and choosing target applications with care.