Serious game development as a strategy for health promotion and tackling childhood obesity 1

ABSTRACT Objectives: to develop and assess a serious game on healthy eating and physical activity to promote health and tackle childhood obesity. Method: a descriptive, applied and methodological study.For the development of the game, the following steps were taken: conceptualization, pre-production with the development of the game documentation, prototyping, production and assessment of thecomputer and health experts. Results: a prototype has been developed up to beta version. The game was positively assessed both in terms of gameplay and mechanics, and in relation to the content presented, standing out as a powerful strategy for health promotion. The information from the assessment phase contributed to the settings in the software in order to make it available in the future for the target population of this research. The greatest advantage of the proposed game is the fact that it is an open educational resource. Conclusions: the expert assessments showed that the game has great educational potential and it is considered suitable for future application to the target audience.The serious game can become a technological teaching resource available for use in schools and health facilities, and can also be reused for the production of other educational games by accessing its source code.


Introduction
The global and Brazilian panoramas on obesity have emerged as a new challenge for public health because its incidence and prevalence has increased alarmingly in the last 30 years (1) . In 2010, it was estimated that 43 million children in the world are already considered overweight and suffering from obesity (2) .
In order to minimize the problem of overweight and obesity, health policies in Brazil and in the world have established a series of interdisciplinary and multisectoral objectives with the aim of promoting health (3)(4) .It is noticed the need to use different strategies to achieve health education, especially those focused on children, such as games (5) .
An educational approach based on electronic games may include entertaining features and specific content to promote the child's learning process (6) . The use of games and fun activities may be a useful tool and well accepted by children to achievethe health education goals.
It is highlighted in this scenario, the importance of integrating the serious game in the educational context.
A serious game is a game in which education, in its various forms, is the main objective (7) . These games promote learning and behavioral changes (6) .
In studies published in the scientific literature, serious games were used as educational tools in an innovative way. These games have been used successfully in the area of health, which helps in the treatment of children and adults with chronic diseases (such as diabetes, asthma and cancer) or under psychotherapeutic treatment (8)(9) .
In this context, the aim of this study was to develop and assess a serious game about healthy eating and physical activity to promote health and tackle childhood obesity.

Method
Descriptive, applied and methodological study, with the purpose to develop and assess a serious game with computer and health experts. This type of study involves the development, validation and assessment of technological tools and research methods (10) . The studies carried out by Schell (11) and Novak (12) supported the methodological design and construction of the required documents.
As for the literature of game design, a game can be understood as the composition of four elements, considered as the elemental tetrad: mechanics, aesthetic, narrative and technology. Mechanics is the operation of the game, narrative is the sequence of events during the course of the story to be told, esthetics is composed by audiovisual components and emotions, while technology is represented by the media (11) . As for the methodological approach, a game can be developed from five stages: concept, pre-production, prototype, production and post-production (12) .
To develop the serious game proposed in this study, the following steps were taken: conceptualization, pre-production with the development of the Game Design Document (GDD), prototyping, production and assessment of the experts.
In addition, studies and researches in the areas of design and assessment of educational games were performed by means of weekly meetings with participation of the students and teachers responsible for the project. It was also carried out a survey on the demands of content with nutrition professionals and the use of iterative cycles, that is, cycles in which it is possible to return to any previous stage whenever it is necessary in order to improve the development of the game. Subsequently, the design and construction of the game were performed based on the identified needs.
The iterative cycle of the game at issue started with the design and development of the initial idea, which was presented to the team and after several suggestions, the production of the low-fidelity prototype began. Subsequently, after the survey and resolution of the problems of this stage, a phase of high-fidelity prototyping started. At the end of this phase, content and computer experts were invited to assess the latest version.
The assessments were carried out by computer experts regarding the usability and procedure issues, as well as assessments of educational content by health experts, considered as experts on the subject. In the assessment of the first playable version of the serious game, semi-structured questionnaires based on the EGameFlow method for assessing educational games were used (13) , adaptated for educational games and derived from the GameFlow method, which focuses on the assessment of games. This questionnaire was divided into seven categories (Concentration, Challenges, Autonomy, Clarity of Objectives, Feedback, Immersion and Improvement of Knowledge). The items of the instrument ranged from 1 to 7, where 1 isconsidered as "weak" and 7 as "strong". In this study, the criteria with the final average equal to or less than 6 Dias JD, Mekaro MS, Lu JKC, Otsuka JL, Fonseca LMM, Zem-Mascarenhas SH.
have been considered as items that must be rethought in order to improve the final version of the game (13) .
The data collection instrument used in the assessment of the experts was initially translated, adapted and previously applied for the assessment of educational games, by the Laboratory of Learning Objects (LOA) (14) , an interdisciplinary environment for the study and research of new methodologies and technologies for the development of games and Open Educational Resources (OER), and permission from the authors was required for the use of the instrument.
For the assessment of the game proposed in this study, 10 assessors were selected: six content experts with a degree in health (nutrition and nursing) and at least one year training andmaster's degree, as well as experience with the theme health technologies for assessment of content, and four computer experts with a degree (computer science and systems analysis) and at least one year training andmaster's dregree in the areas of software development and/or digital learning games, to assess the gameplay,mechanics and game interface.
The assessors were chosen according to an adaptation of the Fehring Model (15) , for the selectionof the specialists. They were screened through a search at Lattes Curriculum and it was requested to the first experts selected to indicate other assessors with the same characteristics. An email was sent to 12 experts to invite them to participate in the survey and clarify the objectives and methodology used, however, two refused to participate because they were on vacations or maternity leave. After the acceptance of the 10 assessors, it was arranged a time and place for onsite assessment of the game, followed by the application of the EGameFlow questionnaire.

Results
The serious game was named as DigesTower and developed by four undergraduate students (Computer Science, Nursing, Music and Image and Sound) and a Master's student in Nursing, under the coordination of Professors in the areas of Computer Science and Nursing.
Since this is an interdisciplinary group, the game was developed according to a collaborative and balanced approach. Illustrators and programmers were engaged in drawing up a fun and functional mechanism, while the teachers and students responsable for the content to be inserted in the game discussed and developed a meaningful and educational learning system, in order to overcome the major challenge of the project: prevent that the educational goals were overshadowed by the narrative and other elements.
To assist in the development of the game, the team relied on a set of activities such as brainstormings; literature searches; development of script and documentation; development of audiovisual components; coding and then, tests and assessments.
Some of the features of the DigesTower game are described as follows.
Game Summary: DigesTower has the human digestive system as background and is classified as a tower defense type of game. Tower defense games can be classified as a subtype of strategy game, and as their name suggests, they are focused on the defense of an element of the game (16) .The game has school children as its target audience.The main character is called Elise.  (Figures 1 and 2). The towers represent the digestive enzymes and are also not shown in the reliable format of the actual enzymes (Figure 3).
Rev. Latino-Am. Enfermagem 2016;24:e2759.  Defense games. In these games, the "enemies" appear grouped and move towards the end of the stage in which the main target is. The player has a pre-defined space and uses a defensive strategy (16) .In the case of The source code is shared with the free software community through Git Hub system.
Expert assessments: The first functional version (Alpha) of the game was submitted toa more accurate assessment by health and computer experts, that is, a version that can be played in full, but still contains bugs and undefined elements (12) .
The computing assessors had a dregree in Computer Science and Systems Analysis. Two participants were male and two females and the age ranged from 22 to 30 years. The health assessors had a degree in Nutrition and Nursing. All six assessors were female and aged between 23 and 37 years old.
The expert assessments were performed using the EgameFlow questionnaire (

Discussion
In the health sphere, the serious games have been used in different contexts, exploring the immersion of players to achieve educational goals (17)(18)(19) . At the end of this study, it was noted that the objectives have been achieved and it was possible to analyze the repercussions of the serious game as an educational technology, along with the experts. It also was found that the game has an innovative and educational potential according to the assessors.
In great concern in combining the educational objectives with the gameplay, and therefore the game had the participation of educators and health professionals from its design to its implementation.
One of the biggest advantages of the proposed game is that it is a free and open educational resource.
The DigesTower can be considered as a resource for technological education with free access for use in schools and health facilities, and can be reused for the production of other games in the area through access to its source code.
It may be noted that the identification of the player with the serious game, through immersion, favors the entertainment and development ofthe teaching and learning processes (20) . In this regard, it was sought to meet these demands during the DigesTower game design. During the development process, it was sought to combine aspects of learning with the interface, audio and esthetics, providing a greater immersion and adhesion of the player, in order to achieve the proposed educational objectives.
Furthermore, the serious game has proven its importance and suitability through the assessment by the experts in the fields of health and computing, which reinforces the importance of the validation stage and corroborates the findings of other studies on the validation of serious games in the area of health (21)(22) .
The main deficiency found has been the lack of opportunity to test the game with the target audience to achieve more effective results and the possibility of validation of the game in practice as an intervention.
Thus, it is intended to combine the use of the serious game with strategies for the prevention and treatment of childhood obesity, since studies show that there has been a meaningful return on the use of this type of tool with this public (19,23) .
Thus, it is intended to improve the game through refinements and to continue the tests with the target audience in future studies, in order to subsequently insert it into educational programs that address obesity. Through the assessments of the computing and health experts, it was possible to notice that the game has great potential as an educational tool, considering that it was well assessed both regarding its mechanics and gameplay, and regarding the educational content since it was considered appropriate for future application in the target audience.
São Carlos, who engaged incessantly to achieve the development of educational games.