Music has long been acknowledged for its effects on participants in sports and exercise. For casual runners music may act as a motivator and distractor of physical strain. It may also serve as a training guide, when sensing technology is used as an enabler for adapting music to a runner’s situation in real-time. While many effects of music are known from sports science and psychology, application designers lack a consolidated knowledge base that guides them in designing a running application. This work synthesizes findings from the involved disciplines and provides 7 requirements for an application that increases casual runners’ motivation and controls training.