Synchronized online gymnastics could provide new possibilities for enhancing the physical and social well-being of people with restricted mobility. We propose a prototype platform for this – Online-Gym – which allows users to interact using a Microsoft Kinect and participate in on-line gymnastics sessions. In this paper we present the Online-Gym concept and a first iteration on the platform architecture that allows interaction in virtual worlds with movement captured by a Kinect device. The exploratory work done so far makes evidence that this approach opens significant opportunities and these scenarios may be further developed, enhanced and enriched.