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\begin{document}

\title{Mission Possible: Using visual feedback to improve physical activity in children}


\author{Gerrit Niezen}
\affil{Affiliation not available}

  
\author{Kelly Mackintosh}
\affil{Affiliation not available}
  
\author{Parisa Eslambolchilar}
\affil{Affiliation not available}
  
\author{Elvis Lesha}
\affil{Affiliation not available}
  



\date{\today}

\maketitle

\selectlanguage{english}
\begin{abstract}
This paper describes the deployment of a novel ubiquitous behaviour change system for social interaction and reflection amongst school children. For four weeks, a class of schoolchildren (Year 5) was monitored with Fitbit activity monitors and their daily physical activity was visualised on a custom ambient display. In addition, video segments describing mission-based activities were shown on tablet devices to the children at the start of each week. The ambient display would indicate if they performed better than the previous day. We describe how the system was designed and developed, present findings from the in-the-wild study, and provide design guidelines for future studies.
%
\end{abstract}%



\section{Introduction} 

It is well established that peadiatric obesity is associated with numerous health implications in later life \cite{Freedman2007}. Despite evidence to suggest that the prevalence of obesity has plateaued in recent years within the UK \cite{Boddy2010} and internationally \cite{Rokholm2010}, there is no evidence of a decline, and a high proportion of children remain at risk of morbidity. Physical activity and sedentary behaviour are key variables implicated in childhood obesity due to their influence on energy balance \cite{Rowland2004}. Current physical activity guidelines recommend children between 5 and 18 years of age to engage in at least 60 minutes moderate-to-vigorous physical activity every day \cite{DOH2011}. Despite this, children, on average, are insufficiently active \cite{Hills2011} and engage in excessive sedentary behaviour. Specifically, only 41 percent of boys and 30 percent of girls in Wales meet these recommended guidelines\footnote{http://www.bhfactive.org.uk/young-people-key-facts/index.html}. Moreover, according to the Department of Health, more than 30 percent of 5 to 12 year old children in the UK are obese, with Wales leading at 36 percent\footnote{http://www.dh.gov.uk/health/2012/04/obesityfacts/}. 

Many interventions have been conducted to reverse childhood overweight and obesity, employing a variety of strategies to enhance levels of habitual physical activity and reduce time spent in sedentary behaviours. Schools have been identified as a key context to implement such physical activity promoting interventions, given that children spend, on average, 40 percent of their waking time there \cite{Fox2004}. Despite this, school-based interventions have been conducted with varied success \cite{Summerbell2005}, which could be attributed to the different intervention strategies and variable methodological quality, such as lack of objective measurements of physical activity \cite{Mountjoy2011}. Furthermore, interventions targeting reduced sedentary behaviour tend to discourage highly valued behaviours, such as engagement with technology. Therefore, there is a need to integrate such technological behaviours into future interventions. Some interventions have sought to do this. Specifically, ambient displays, also known as glanceable displays, which are peripheral, aesthetically pleasing displays of information that support awareness of some data, can be utilised to make information visible in an appealing and socially interactive manner. They are designed to be looked at occasionally without distracting us from our activities \cite{Rogers2010}.Consolvoetala et al. \cite{Consolvoetala08,Consolvoetalb08} integrated an interactive mobile fitness application with a glanceable display finding that those individuals utilising an awareness display maintained their physical activity levels better in comparison to those with no ambient display. However, such devices have inherent problems, such as monitor placement \cite{Trost2005}, and have not been incorporated into a community-based settings, especially targeting children. Therefore, the aim of the present pilot study was to utilise ambient displays in order to provide near real-time visual feedback on physical activity levels during school time. 











\section{Related Work}

Since the birth of ubiquitous computing (ubicomp), monitoring health-related behaviour has become more accessible for a wider age group of people. The potentials of the emerging generation of ubicomp technologies are moving beyond step-counting and physiological monitoring to goal-sharing and information provision systems. This section of the paper reviews some prominent ubicomp technologies that have been used to promote physical activity, in particular walking.

\subsection{Personal Activity Monitoring Devices/Apps}

The simplest of self-monitoring devices are pedometers. Such devices have long been of interest to health promotion professionals for their ability to encourage more active lifestyles \cite{Bakeretal08,Copelton10}. It has been shown that their use can lead to increased walking \cite{Croteau04,ThomasWilliams06} and moderate weight loss \cite{Richardsonetal08}. However, health promoting physical activity interventions have usually used pedometers alongside other resource intensive support and promotion activities, such as classroom training and face-to-face motivational sessions \cite{Bravataetal07,Kangetal09}. Pedometers exist either as dedicated devices whose sole purpose is to measure step count, or as embedded features in other equipment such as mobile phones. This dedicated nature of pedometers also presents barriers to their use, particularly for those less committed to physical activity. Users have to be committed enough to fitness and lifestyle-change to both purchase the pedometer and then remember to wear or carry it. Furthermore, questions of fashion, design and convenience can deter people from using such devices \cite{Consolvoetal06}. 

In addition to collecting physical activity-related data, some personal monitoring devices also include feedback on performance. Examples include: i) the Nike+ iPod Sport Kit\footnote{\url{http://nikerunning.nike.com/nikeos/p/nikeplus/en\_US2}} MP3 player, which tracks individual exercise levels and interrupts music to verbally report on progress; ii) the Pediluma \cite{Limetal11}, a shoe accessory that tracks wearers' physical activity and produces a visualisation of activity levels by varying the intensity of LED-lit custom-built enclosures that contain Arduino boards; and iii)  systems such as foot pods\footnote{e.g. Garmin (\url{www.garmin.com}), Polar (\url{www.polarusa.com}) or Sigma Sport (\url{www.sigmasport.com})}, Jawbone UP\footnote{\url{https://jawbone.com/up}}, Misfit Shine\footnote{\url{http://www.misfitwearables.com/}} and FitBit\footnote{\url{http://www.fitbit.com}} monitor various activities throughout the day and synchronise the data almost in real time to a mobile app or a web-based interface, where they are used either in an online coaching system or as an input to a virtual competition with a computer-generated partner.

Mobile-phone based pedometer apps\footnote{e.g. MapMyWalk \url{http://www.mapmywalk.com/}} have the advantage of being embedded in equipment that people already own and keep attached to them. Smartphones offer various sensors to infer and record physical movements throughout the day and provide a convenient platform to give feedback about activity levels. Their in-built display and communication capabilities allow users not only to view their feedback but also to share it with others. As a result, smartphones are increasingly being used to address the problem of sedentary lifestyles \cite{Consolvoetalb08,Fogg98, KingTester99}. Some mobile apps also allow the diarisation of physical activity data in order to provide additional motivation for physical activity \cite{Slootmakeretal09}. That said, to accurately measure and validate physical activity levels, there needs to be a consistent monitor placement \cite{Trost2005}, which is highly unlikely when integrated into mobile devices. 


\subsection{Social sharing and team working }

Sharing physical activity data with friends and peers and participating in team-based physical activity games have been an emerging research theme in HCI and non-HCI literature in the past few years. The following sections review some examples published in the HCI literature that have applied the power of participating in physical activity as a team, social sharing and peer support.

\subsubsection{Social fun and games}

Playfulness and enjoyment are important for the achievement of changes in physical activity levels because they stimulate positive emotional states that help to motivate increased physical activity \cite{Blytheetal04}. Several physical activity games attempt to make use of this effect. In one such game, Fish'n'Steps \cite{Linetal06}, users are presented with a fish avatar whose growth, emotional state and behaviour reflects the participant's recent physical activity. Moreover, Fish'n'Steps includes behavioural goals in a team-based game, with the team-members being responsible for the health and growth of their fish in a shared fish tank. Consistent with the findings in Blyth et al. \cite{Blytheetal04}, the evaluation of Fish`n'Steps showed rather than provoking increased physical activity, an unhappy avatar (sad or unhealthy looking fish in this example) could cause users to simply stop using an app. In Neat-O-Game \cite{Fujikietal07}, a wearable accelerometer provides data that is used to control an avatar that represents the player in a virtual race. Multiple players can participate in Neat-O-Game. Winners are declared on a daily basis and players can use activity points that they have gained to receive hints in mental games such as Sudoku that are included in the app. In a different example, rather than trying to motivate individuals to reduce the time spent on sedentary activities, Berkovsky et al. \cite{Berkovskyetal09b} focus on integrating physical activity into the predominantly sedentary activity of computer gaming.  Berkovsky et al. \cite{Berkovskyetal09b} integrate a novel game design called "Play, Mate!" into an open source game called Neverball and raise players' motivation by increasing the difficulty of the game and including elements of physical activity. Berkovsky et al. \cite{Berkovskyetal09b} conducted an experimental evaluation of Neverball involving 180 users aged 9 to 12 unfamiliar with this game. They divided participants into two groups:  90 played the sedentary version of Neverball and 90 played the active version of Neverball. The experiment showed that children performed more physical activity and decreased sedentary playing time when they used the active version of Neverball. Furthermore, children did not report any reduction in their enjoyment of playing.

Social games, which encourage physical activity, are not limited to desktop or fixed platforms. Such games are rapidly growing in the smartphone market. For example, Ahtinen et al. \cite{Ahtinenetal10} designed a team-based mobile wellness app called "Into", which visualised the number of steps for its users with an analogy of a virtual trip from one place to another. As the team members took steps, the application combined the achievements of each team member and visualised the combined progress as a trip between the departure and destination places. Ahtinen et al. conducted a qualitative pilot study with 37 participants (a total of 12 people in four teams) over a period of one week. The more participants took steps, the quicker the line between the places turned to green (achieved goal). The line between the departure and destination places reflected the true distance between the places in the physical world, and respectively the users needed to take as many steps together as the real distance required. The findings from this study showed that setting departure and destination places and viewing up-to-date progress between them can motivate individuals. However, Ahtinen et al. did not report on the impact of feedback and or goal-settings on physical activity.

\subsubsection{Sharing data}

There is an abundance of research in HCI literature relating to social sharing as a tactic to increase awareness and to promote physical activity \cite{Andersonetal07,Consolvoetal06,harries2013,ToscosFaber06}. For example, Shakra \cite{Andersonetal07}, Houston \cite{Consolvoetal06}, and Chick-Clique \cite{ToscosFaber06} not only allow individuals to self-monitor and set personal goals but also allow groups of friends to share performance data using mobile platforms. These systems integrate social influence through social facilitation and social support. bActive, a smartphone app \cite{harries2013}, employs a social norms approach, showing people what other people do, in order to influence them. Harries et al. investigated this approach amongst 152 young to early middle-age men through a rigorous and large-scale field trial. Unlike most similar active-lifestyle apps, bActive does not need to be activated prior to participating in physical activity and needs no special additional equipment. As a result, it requires minimal initial commitment from the user. The longitudinal data analysis of 6-week randomised control trial of the bActive shows that the number of steps the 22-40 year-old participants walked was 64\% higher, on average, if they used the bActive app. 

Foster et al. \cite{Fosteretal10} included the social sharing feature in Step Marton, a Facebook app, to create social and competitive context for daily pedometer readings in order to motivate physical activity at the workplace. They studied two versions of the app (social vs. individual) with 10 nurses (1 male) over a period of 21 days and claimed that the total number of steps taken was significantly higher when participants used the social condition ($Z= -2.5, N=10, p=0.013$). 

Unlike games such as Fish'n'Steps \cite{Linetal06} where the competition is explicitly introduced, Houston \cite{Consolvoetal06} and Chick-Clique \cite{ToscosFaber06} users do not explicitly compete with one another but can view and comment on the progress of their peers. During a three-week evaluation of Houston with young female friends (N=13) Consolvo et al. claimed that the sharing groups were significantly more likely to meet their goal ($t=2.60, p < 0.05$). They also reported that average daily step counts increased from the baseline week to the two weeks for seven participants in social sharing groups with goal sharing: daily averages exhibited increases from between 5\% to 61\% extra steps (median increase: 30\%); the average daily step count increased from 180 to 4,587 steps/day (median: 2,234). Shakra \cite{Andersonetal07} tracks the daily physical activities of people, using an Artificial Neural Network (ANN) to classify different activities throughout the day. In a short-term study (10 days) of the prototype that shared activity information amongst groups of friends and or co-workers (an average of three people in three groups), Anderson et al. reported that awareness encouraged reflection on, and increased motivation for, daily activity. In Chick-Clique \cite{ToscosFaber06} the step counts of teenage girls were recorded by pedometers and automatically transmitted to peers' and friends' PDAs for sharing. Some teenagers participated in this study expressed concern with regards to negative effects of competition i.e. excessive physical activity levels damaging their friendship. However, some said that it helped them to become more comfortable about talking about physical activity engagement with their friends.

Although there are many examples in the HCI literature which have included social sharing to promote physical activity behaviour change, the effectiveness of this method is unconvincing. For example, the relatively short but big sample size in the bActive study did not find any evidence to suggest that social norms are an essential component of such an app; instead the study found that the impact of feedback limited to individual performance exhibited no significant difference to that of feedback that also included social data. The relatively short data collection periods and small sample size utilized raise questions about the claims made for Step Marton, Houston and Chick-Clique. Moreover, given the lack of precision both in terms of assessing baseline levels and the limited time period over which Houston study data were collected raises doubts over the efficacy of the conclusions drawn, and the sustainability of the changes observed. As with the Shakra pilot study Anderson et al. only observed some encouragement among 'buddies' and, in some cases, strong competition but they did not do and or report any quantitative or qualitative analysis on physical activity measures. 



\subsection{Goal-setting and Feedback}

Goal-setting is considered a key feature of technologies intended to encourage physical activity \cite{Consolvoetal06}. The most prominent approach to determining physical activity goals can be found in Chick-Clique \cite{ToscosFaber06}, where users set their own daily step-count goals. In this example, the locus of control remains with the user, who has to determine the degree of change that he or she wants to make. One potential problem with this approach is that it relies on the user to set an appropriately challenging goal. If users set goals are either too difficult or too easy, they can fail to inspire change \cite{Pearson2012}. To avoid setting inappropriate goals, Houston \cite{Consolvoetal06} and Fish'n'Steps \cite{Linetal06} automatically create each user's step-count goal based on their baseline step-count. UbiFit Garden \cite{Consolvoetala08,Consolvoetalb08}, a mobile fitness app, consists of a fitness device, an interactive application and a glanceable display. The goal attainment in this system is tracked through the glanceable display (i.e., how well the garden is looked after). The interactive application includes detailed information about an individual's physical activities and a journal where activities can be added, edited, and deleted. The study showed that participants who had an awareness display were able to maintain their physical activity level better than did participants who did not have such a display.

Feedback in Chick-Clique was presented to users in the form of text messages, whereas Houston, Fish'n'Steps and UbiFit Garden provided visual feedback to the users when daily goals were achieved. Feedback varied and ranged in complexity from an asterisk annotation in Houston to the development of animated characters in Fish`n'Steps. The motivation behind the development of a character goes beyond the straightforward mechanism of feedback, aiming to cultivate "a strong internal locus of control through care of pet or plants". In the case of UbiFit Garden the individual's level of physical activity was reflected in the "liveliness" of a garden environment visualised on the individual's mobile phone screen. 

Other researchers have started to investigate the potential for the use of ambient persuasion, in which visual feedback about physical activity levels is presented peripherally, such as through an augmented mirror\footnote{A technology that uses a one-way mirror to achieve an intuitive augmented reality environment}  \cite{FujinamiRiekki08} or using tablet-based information visualisation methods \cite{fan2012}. In all the technologies reviewed in this paper, feedback either through a visual or a music/haptic display has been present and has shaped a significant part of the choice architecture depending on the negative or positive nature of the feedback. In the other hand, goal-setting is rarely used as a standalone motivational tool. More commonly, it is framed within the context of games \cite{Ahtinenetal10,Berkovskyetal09a,Gasseretal06,Linetal06} or social awareness applications \cite{Consolvoetal06,Toscosetal08} that explicitly introduce aspects of teamwork, competition and social facilitation into the process of behavioural change.


\section{Mission Possible: Ubiquitous Social Goal Sharing}

This paper presents a pilot study using ambient displays to provide near real-time visual feedback on physical activity in a school environment. 

\section{Participants}
All children within Year 5 (9-10 years old) from Bigyn Primary School in Llanelli were invited to take part in the study (n=32). Available resources dictated that this was the maximum number of participants that could be recruited to pilot the intervention, thus statistical methods were not used to determine samples sizes and no control group was measured. Written informed parental consent and participant assent were received from all children (100\% participation rate).

\section{Outcome Measures}
Ethics approval to conduct the study was obtained from Swansea University's A-STEM (Applied Sports Technology Exercise and Medicine Research Centre) ethical advisory committee. After securing the co-operation of the school, all Year 5 children were invited to take part via an information sheet and parents were provided with a consent form to complete if they wanted their child to participate. Additionally, children provided informed assent. 
Baseline data collection measures were completed in April 2013 and post-intervention measures were completed after the 4 week intervention period in June 2013. Children completed the Physical Self-Perception Profile for Children (PSPP-C) \cite{Whitehead1995}. Stature and sitting stature to the nearest 0.1cm (Seca Ltd. Birmingham, UK) and body mass to the nearest 0.1 kg (Seca Ltd. Birmingham, UK) were measured using standard techniques \cite{Lohman1988}. Body mass index was calculated (body mass (kg) / stature2 (m2)) and BMI z-scores were assigned to each participant \cite{Cole1995}. Waist circumference was measured to the nearest 0.1 cm using a non-elastic anthropometric tape and measurements were taken at the narrowest point between the bottom of the ribs and the iliac crest. All measurements were undertaken by the same trained researchers. The 20m shuttle run test was conducted to provide an estimate of cardiorespiratory fitness (CRF). This test has been widely used in children of similar age \cite{EUROFIT1998,Stratton2007,vanmechelen1986}. The total number of completed 20m runs was used as a marker for CRF.
Data were analysed using a mixed ``between-within'' analysis of variance (ANOVA), with group as a between-participant factor and time as a within-participant factor. Statistical significance was accepted at P<0.05. All statistical analyses were conducted using IBM Statistics 21 (SPSS, Chicago, IL). All data are presented as means $\pm$ SD. Statistical significance was accepted when P $\leq$ 0.05.

\section{Intervention}

The design of Mission Possible draws on the principles discussed in the previous section, but differs in a number of key ways from most of the ubicomp technologies. Firstly, Mission Possible allows school children to reflect on the process of increasing their activity levels for each day of each mission in a playful way. Children have to work as a team and ensure that a representative of their team is wearing the Fitbit; there is no requirement for data entry (as is needed for diarisation). Secondly, children get the reward of seeing their activity data without having to make any initial effort, or to remember to switch the recording function or the display on and off. They just have to clip on the Fitbit - the ambient display is already part of their schoolroom environment. 

A third difference concerns goal-setting. Formal goal-setting, training and coaching are replaced in Mission Possible by users' engagement with the information on the ambient display in terms how their team is performing and includes performance of the other teams. As a result, rather than feeling that they are engaging in a formalised exercise program (e.g. physical education), children are allowed to respond to this information in whatever way they wish. As argued by Thaler and Sunstein \cite{ThalerSunstein08}, behavioural feedback forms part of the choice architecture that nudges behaviour. In this case, the feedback from the ambient display nudges children to be little bit more active than a day before; having the LED display right at the front of the classroom allows them to occasionally glance at their performance data during the day.

The fourth difference concerns the structure of the social interaction. Almost all of the work reviewed in the social sharing section focused on participants remotely contributing to their team's goal. For example, Into, Fish'n'Steps, Houston, Shakra and Chick-Clique individual members of teams have a physical activity monitoring device, set goals as an individual or a team and work toward those goals remotely through a digital medium (no face to face interaction with team members happens). Mission Possible breaks away this individualistic digital bubble phenomenon \footnote{Also called Mindless Technology by Professor Yvonne Rogers in her keynote speech at INTERACT 2013 \url{http://www.interact2013.org/Keynotes}} and allows children through shared Fitbits and the ambient display, to be more creative, playful and thoughtful of each other.

Although it differs from other ubicomp technologies in the respects listed, Mission Possible shares with them the desire to be interesting and fun to use. To this end, Mission Possible draws on the experiences and lessons of other systems. It gives positive reinforcement (learning from the success of UbiFit Garden and Houston and from the problems experienced by Fish'n'Steps); similar to Houston, Chick Clique, UbiFit Garden, Into and Shakra, provides opportunities for teams to reflect on their activity. Finally, like the social gaming and social data sharing features of Fish'n'Steps, Houston, Chick-Clique, Shakra and Into, the social norms information within Mission Possible is designed not only to prompt increased physical activity, but also to encourage engagement with the feedback i.e. the displays of their team and others' activity levels.
The intervention design and content were informed by formative work with the children involved, thereby employing a user-centred design. The children were divided into four groups, where each group generated ideas for possible missions. These included ideas like:
\begin{itemize}
\item playing tag with laser guns, bouncy balls or velcro stars
\item who can do the assault course the fastest
\item ``aliens vs. cowboys'' or ``zombies vs. humans''
\item capture the flag
\item hide and seek using climbing wall

\end{itemize}

 We selected feasible ideas from the lists, and generated descriptions of the missions based around a ``secret agent'' type theme:

\begin{itemize}
\item Mission 1: Assault course - ``Captain Cybernetic wants you to infiltrate Dr. Tempus's lair. However, Dr. Tempus has placed various obstacles in your path. Navigate the obstacles to get to his lair as fast as possible.''
\item Mission 2: Code hunters - ``A video clue is shown on the iPad, where you have to find a hidden token. The token must be returned to the teacher, who will reveal the next video clue the following day. The tokens from Monday to Thursday will be needed to find the final token on Friday.''
\item Mission 3: Capture the flag - ``Two teams; where each team tries to get the other team's flag while protecting their own.'' 
\item Mission 4: A race against time - ``Captain Cybernetic has gained access to a high-power laser beam that is powered by your feet. You and your teammates need to work together to rack up as much steps as possible. Your step count will be used together to power the laser beam and destroy the evil Dr. Tempus's lair.''
\end{itemize}


\subsection{Design and methodology}

Children were divided into 10 groups, where each group was assigned a uniquely distinguishable colour to represent their group on the ambient display. Flexible LED lighting was installed along the bookshelf in the front of the classroom. 

The display was connected via a microcontroller to the school's computer network. Activity monitor data were retrieved from the Fitbit website and displayed with moving colour segments, where different colours were used to represent the various teams. The teams could make their colour segment go faster by increasing their number of steps. The team's colour would start to flash if the spent more time being active than the previous day.

For the missions, ideas were elicited directly from the schoolchildren, with a brainstorming activity performed at the school. These ideas were then refined by the project team and turned into four activity-based missions.

\subsubsection{Hardware design}

Ambient displays located in a person's environment have been shown to change their behaviour by providing live feedback \cite{fan2012,harries2013}. These displays serve as decorative visual art pieces intended for reflection.

An ambient display, consisting of a 4m-long lighting strip with 240 individually controlled LED lights, was designed and constructed by Swansea University and installed in the classroom. Data collected from 10 Fitbit activity monitors were visualised on the lighting strip with different lighting patterns. The ambient display connects via a network cable to the Internet in order to download the Fitbit data. 

To visualise the performance of each of the 10 groups, uniquely distinguishable moving colour segments were used. Each colour segment had a speed betwen 0 and 10, based on the group's performance. To calculate the speed of each group we used the following formula:

\begin{equation}
v = 5 \frac{x}{y} + 1  
\end{equation}

where $v$ is the speed at which the segment is moving, $x$ is the accumulated number of steps taken that day, and $y$ is the number of steps taken on the previous day. On the first day of each mission, $y$ was set to 1000 as a default value.

To provide additional encouragement for the children, we used the intensity level (lightly active, fairly active and very active) while they were performing the missions. We compared the number of minutes they spent at the `very active' intensity level to complete the mission on that day with the previous day. If they were doing more vigorous exercise than the previous day, their group's colour segment would start pulsating. 

A DVD outlining the various missions, together with a Teacher's Guide mission pack, was provided to the teacher, and the mission videos installed on a set of tablets belonging to the school.

\subsubsection{Measurement of physical activity}

The Fitbit Zip (Figure \ref{fig:Fitbit}) contains a tri-axial accelerometer to record time-stamped physical activity data, including number of steps and physical activity according to four levels: sedentary, lightly active, fairly active and very active. It can be clipped to various locations on the body. For the study we asked participants to clip the device to the inside of their trouser pocket. The Zip is designed to be small and unobtrusive, making it more acceptable for use by children than other activity monitors which are often large and bulky. A recent study \cite{m_Noah_Spierer_Gu_Bronner_2013} has indicated that the Fitbit is reliable and valid for activity monitoring (in terms of step counts).
 
Data from the activity monitors were uploaded automatically to Fitbit's servers as the children returned from completing the mission for the day, via a Bluetooth Low Energy (BLE) dongle connected to a computer in the classroom. Data was accessed using the Fitbit API, analysing the results and storing them on the university's server. The results were then downloaded by the Arduino (see Figure \ref{fig:arduino}), connected with an Ethernet shield to the internet via the school's network. Note that the activity monitor was worn from the start of the activity until the end of the activity, and not the entire day.

The Fitbit trackers syncs to the Fitbit servers every 15-20 minutes, as long as they are within 15 feet (approximately 5 metres) of the BLE dongle. Each Fitbit tracker has its own ID, which means that one BLE dongle can sync multiple devices. Whenever new data is available on Fitbit's servers, it is synchronised with our university server. It takes approximately 1-2 minutes to transfer all the activity data from the Fitbit servers. The Arduino polls the university server every 5 minutes for the results to be displayed on the ambient display.\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/fitbit/fitbit}
\caption{{Fitbit Zip activity monitors
\label{fig:Fitbit}%
}}
\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/hardware/hardware}
\caption{{\label{fig:arduino}
Hardware used for ambient display: Arduino microcontroller with Ethernet shield, connected to WS2811 RGB LED strip (60 LEDs/m)%
}}
\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/display/display}
\caption{{Ambient display installed against a bookcase in the corner of the classroom%
}}
\end{center}
\end{figure}

\section{Results}

To complete all four missions, the children spent approximately 3,290 minutes (equivalent to 55 hours). They were able to take 159,549 steps during this period of time.

For Mission 1, the teacher recorded the time (in seconds) required for each team to complete the assault course using a stopwatch, as shown in Figure \ref{fig:mission1}. As the Fitbit for the yellow team was malfunctioning on the Tuesday, they did not compete that day. Figure \ref{fig:fit1} shows the amount of physical activity performed (in minutes) by each team for each day of the week, where the stacked bar is showing the level of physical activity. The number of steps recorded by the Fitbit is also plotted on the same graph, and can be read on the second y-axis to the right of the graph.

In Figure \ref{fig:mission2} the time to find the token for Mission 2 (in minutes) is shown for each team. On the Monday the silver team spent a large amount of time (23:10) compared to other days in order to find the token. As such the data point was shortened to make the graph more readable. The data recorded by the Fitbit is shown in Figure \ref{fig:fit2}.

The number of points scored during Mission 3, recorded by the teacher and grouped by team, is shown in Figure \ref{fig:mission3}. The related Fitbit data is shown in Figure \ref{fig:fit3}. Figure \ref{fig:mission4} shows the time taken (in seconds) for each team to complete Mission 4, as recorded by the teacher using a stopwatch. The Fitbit data for Mission 4 is shown in Figure \ref{fig:fit4}.


Overall, there were no significant differences in any physical self-perceptions over time (P>0.05). Results are shown in Table \ref{tab:psppc}.\selectlanguage{english}
\begin{table}
% table caption is above the table
\caption{{{\bf Table. Physical self-perceptions.} \emph{Note:} Values reported as mean $\pm$ SD}}
\label{tab:psppc}       
\begin{tabular}{lllllll}
& Sport \newline competence & Physical \newline condition & Body \newline attractiveness & Perceived \newline strength & Physical \newline self-worth & Global \newline self-esteem  \\
\noalign{\smallskip}\hline\noalign{\smallskip}
Baseline & $2.96 \pm 0.13$ & $2.95 \pm 0.12$ & $2.81 \pm 0.14$ & $2.91 \pm 0.11$ & $3.07 \pm 0.12$ & $3.26 \pm 0.11$ \\
Post & $2.88 \pm 0.14$ & $2.88 \pm 0.14$ & $2.97 \pm 0.16$ & $2.89 \pm 0.12$ & $3.10 \pm 0.13$ & $3.31 \pm 0.13$  \\

\end{tabular}
\end{table}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Mission1/mission1}
\caption{{\label{fig:mission1}
Time to finish the assault course (Mission 1), grouped by team%
}}
\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/fit1/fit1}
\caption{{\label{fig:fit1}
Mission 1 - amount of physical activity; number of steps%
}}
\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Mission2/mission2}
\caption{{\label{fig:mission2}
Time to find the token (Mission 2), grouped by team. The bar for data point 23:10 was shortened to make the graph more readable.%
}}
\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/fit2/fit2}
\caption{{\label{fig:fit2}
Mission 2 - Amount of physical activity; number of steps for each each group%
}}
\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Mission3/mission3}
\caption{{\label{fig:mission3}
Number of points scored during the mission (Mission 3), group by team%
}}
\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/fit3/fit3}
\caption{{\label{fig:fit3}
Mission 3 - Amount of physical activity; number of steps for each each group%
}}
\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Mission4/mission4}
\caption{{\label{fig:mission4}
Time in seconds for each group to complete Mission 4, grouped by team%
}}
\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/fit4/fit4}
\caption{{\label{fig:fit4}
Mission 4 - Amount of physical activity; number of steps for each each group%
}}
\end{center}
\end{figure}

\section{Discussion}

This study underscores the value of games in not only increasing children's awareness of their physical activity levels, but encouraging them to increase them. Such an approach can foster long-term behavioural change and therefore future research should seek to incorporate longer intervention periods. The present pilot study, as opposed an observational or randomised controlled trial, reports the effects of the design choice and offers specific component guidance, which could be refined for future research. 

\subsection{Mission 1}
As shown in Figure \ref{fig:mission1}, the fastest teams completed the assault course in less than 80 seconds, but were active for around 10-20 minutes during the session. This shows that the time spent engaging with the activity itself does not have to last the whole session to be effective. For this activity, the time spent \emph{very active} (as shown in Figure \ref{fig:fit1}) does not seem to be increasing or decreasing significantly over the week, probably due to the total engagement time being so short.

While some teams (e.g. red, purple) seem to have improved over the course of the week, this was not the case for all teams. Care should be taken if the metric ``complete activity faster than previous day'' is used as a trigger for a motivator, where the motivator is e.g. a short animation or motivational piece of text.

\subsection{Mission 2}
The time spent finding the token (Figure \ref{fig:mission2}) is quite variable across the different days of the week, given the nature of the activity. However, completing the mission quickly (e.g. the green team on Monday, Wednesday and Thursday) did not necessarily mean that they would spend less time being active during the entire session.

One outlier is the silver team, which took an unusually long time (23:10) to find the token on the first day. This is also reflected in their step count and amount of physical activity, as shown in Figure \ref{fig:fit2}.

\subsection{Mission 3}

This mission stimulated the largest amount of physical activity during the session compared to the other missions. Teams consistently spent at least 10 minutes active during the session, with high levels of being fairly active and very active. 

\subsection{Mission 4}
In this mission, where teams were specifically asked to try and increase their step count compared to the previous day, the amount of physical activity performed fluctuates throughout the week. The time recorded as being very active is less than with Mission 3.

\subsection{Implementation issues}

One of the biggest obstacles during the installation of the ambient display was trying to establish a connection to an internet server via the school network. As we were using an Arduino microcontroller with an Ethernet shield, it was quite challenging to negotiate network authentication via the school's proxy server. If possible, it is recommended to use a GPRS/GSM shield or similar when installing Internet-connected prototypes in-the-wild, as the existing network infrastructure could cause unexpected problems.

It can also be challenging to come up with ten easily distinguishable colours using RGB LEDs. When mixing RGB colours using LEDs, the colour black is not available, and it becomes difficult to tell the colours brown and orange apart. Figure \ref{fig:colours} show the final colour palette we came up with.

Other practical considerations include that if you want the teacher to provide data, give a template with the required format. This helps to not have to unnecessarily transcribe data, for example converting ``1 min 48 sec'' to ``00:01:48''.\selectlanguage{english}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/colours/colours}
\caption{{\label{fig:colours}
Colours used on the ambient display to represent the ten teams, with hexadecimal colour code used in  parentheses%
}}
\end{center}
\end{figure}

\section{Conclusion}

Though some children's BMI decreased, this was not statistically significant. In order to ascertain a more accurate interpretation of the intervention effect, the intervention would need to run for longer, have a comparison group, and have a greater sample size. Moreover, future interventions should consider intervention fidelity and incorporate a more thorough process evaluation. That said, teacher and children's feedback was that all children exposed to the intervention enjoyed participating in physical activity, regardless of whether they previously enjoyed such physical activities.

\section{Acknowledgements}

Funded by the Creative Exchange Wales Network (CEWN). This work was also supported by the UK Engineering and Physical Science Research Council [EP/G059063/1]. A DVD containing the weekly mission video segments, together with a Teacher's Guide mission pack, were designed and created by our creative partner, Redhead Consultancy. We would also like to thank everyone at Bigyn Primary School who assisted us during this study.

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