## 5 Discussion and Future Developments  
The results obtained through the evaluation--both the tests and the direct observation of users--lead us to suggest the added value of HybridPLAY as a tool for the physical and cognitive activation of older people, with the potential of encouraging their involvement and improving the playful aspects of the system in accordance with their interests and possibilities. However, the results of the questionnaires reveal that the perception of usability has decreased with respect to a previous study carried out with children and young adults in Reference [, and that not all users expect to do more exercise because of the HybridPLAY system. In this regard, it is important to highlight that, unlike other groups of ages, it is quite common that senior people suffer from minor, but painful traumatological problems, which somehow reduce their desire to do exercise. Vision impairments are also more common in seniors than in younger people. Although we did not collect direct evidence that the lack of brightness or the size of the screen has a more dramatic effect in seniors than in children, the games are shown on a mobile phone, which has the disadvantage of being difficult to see in outdoor environments. In addition, technology acceptance is sometimes a problem for some senior adults, who may feel disengaged with respect to new devices and technologies. Therefore, it would be unrealistic to expect the same degree of enthusiasm for exercise and technology observed in children, a statement that is aligned with the results obtained with the experiments, both at the quantitative and qualitative levels. In addition, the users who participated in the experience reported very low previous experience with video games and OFE, something that may explain some of the responses. In any case, the tool obtains a mean level of acceptance in terms of usability and a good level of acceptance in terms of satisfaction. This suggests that further research in this area is worth doing. These first approximations about the use of HybridPLAY with senior adults have revealed interesting aspects we hope to deepen in future research, because of their potential as a tool to promote outdoor exercise among the elderly. The preliminary indications obtained so far suggest us that:  
* The system is well perceived by part of older people and they generally recommend it (question 6 in Table 3), although there are some cases where the technology is not perceived in a completely positive way. * The system has the potential to favor exercise and cognitive training of the elderly through coordination (body-speaking, body-listening) and concentration. Users agree that the collaboration with other people is very easy with HybridPLAY (question 4 in Table 3). * The system has a potential use in rehabilitation programs in the case of injuries and training plans that can be monitored through the mobile application. * The system has the potential to establish gamification strategies that encourage the elderly to go to the park and exercise. * The system can be used, for instance, by children accompanied by their elders in children's playgrounds and by the elderly in collaboration with younger people in OFE for the elderly. As shown in Figure 5, HybridPLAY can be used by persons of different ages. Therefore, we propose the following future actions in our research:  
* A study to adapt the sensor to the various OFE for the elderly. This study should include an analysis of possible hardware and installation complications that could potentially jeopardize the use of the system because of technology rejection. The system should be as simple as possible to avoid any possible negative perception. * Developing a specific training game with different phases and levels, incorporating gamification, reward systems and even communication strategies in social media (e.g., including the score, unlocking games as training progresses, etc.).