Physical activity plays a key role in the prevention and delay of health problems associated with sedentarism in the senior population. Configurable exergames that can be adapted to fit different needs have been proposed to address this issue because they are fun and enjoyable while promoting physical exercise. This paper describes the design process of an integrative system for Exergaming targeting the senior population that combines human-centred and software engineering methods. An initial requirements elicitation was carried out involving 12 health professionals. This resulted in a list of 110 design requirements, such as customization of games and activities, visualization of historical data, management of plans and sessions, and automatic recommendation of games. The software design was developed using the Unified Modelling Language (UML). Finally, we present two iterations with human-centred techniques, namely, card sorting and paper prototype evaluations, which will serve as basis for future implementations.