Designing Group FitnessSwimming Exergames: A CaseStudy

Woohyeok ChoiDept. of Knowledge ServiceEngineeringKAISTDaejeon, South Koreawoohyeok.choi@kaist.ac.kr

Darren EdgeHuman-Computer InteractionGroupMicrosoft Research AsiaBeijing, Chinadarren.edge@microsoft.com

Joohyun KimDept. of Knowledge ServiceEngineeringKAISTDaejeon, South Koreajoohyun.kim@kaist.ac.kr

Uichin LeeDept. of Knowledge ServiceEngineeringKAISTDaejeon, South Koreauclee@kaist.edu

Jeungmin OhDept. of Knowledge ServiceEngineeringKAISTDaejeon, South Koreajminoh@kaist.ac.kr

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AbstractRecently, HCI-related communities have explored ways toenhance conventional group fitness through interactivetechnologies. As one such approach, we considered howto design exertion games (exergames) for group fitness. Inthis poster, we examined group fitness swimming as acase study, and designed SwimTrain, an exergame for thisgroup activity. Our game focuses on helping multipleswimmers set and maintaining an appropriate exerciseintensity through both competition and collaboration. Wealso explored several implementation issues, such as devicesettings, input methods, and game feedback.

Author KeywordsSwimming, exergame, social interaction

ACM Classification KeywordsK.8.0 [Personal Computing]: General-Games; H.5.3[Group and Organization Interfaces]: Synchronousinteraction

IntroductionSince being introduced in the late 1960s, group fitness hasbecome one of the most popular types of exercise.Today’s group fitness includes most forms of exerciseswhich are performed by a group of people and guided byan instructor [10]. We can see this type of exercise almosteverywhere, such as group spinning, swimming, and yogaclasses. The key benefits of group fitness include learning

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new skills, adherence to a training regimen, and increasedenjoyment and engagement.

RAIL

RAIL

RAIL

RANK 1ST!

Figure 1: Visual presentation ofCompartment Ordering

RAILRAILRAILRAIL

CRASH

Figure 2: Visual presentation ofTrain Running

RAIL

NEXT ROUND...

Figure 3: Visual presentation ofTrain Stop

Advances in interactive technologies have spurredresearchers to explore augmentation of conventional groupfitness. One approach is to design a self-quantified toolthat delivers individual/group exercise information; forexample, Mauriello et al. proposed a wearable display forgroup running that shows running pace or duration to agroup of runners [4]. In this work, we consider groupfitness exertion games (exergames) that enable multipleexercisers with different fitness levels and workout goals toperform a set of exercise activities at the same time.

We examine group fitness swimming (e.g., swimminglessons/clubs) as a case study. Fitness swimming is a verypopular aerobic exercise, as it provides a comprehensivefull-body workout. Furthermore, this is a challenging case,as there are limited opportunities for social interaction inthe swimming pool environment [8]. Based on theobservation of group swimming and well-known exergamedesign guidelines [5, 6], we designed an exergame forgroup fitness swimming, called SwimTrain.

We mainly focus on supporting multiple swimmers whohave different fitness levels and workout goals. To thisend, our game design involves collaboration andcompetition. In particular, we employ a competitiveaspect to facilitate users’ engagement with socialcompetition, as well as to help determine the targetexercise intensity. In the collaborative period, swimmersare represented as train compartments that are overlaidon a virtual circular lane. The aim is to avoid collisionsbetween compartments by collaboratively maintainingtheir individual target intensity. We also consider what isrequired to implement SwimTrain, such as estimation ofphysical intensity and method of delivering social presenceto users.

SwimTrainTo design SwimTrain, we first observed group swimming.When swimming in a lane, each swimmer maintains anappropriate distance from those nearby (i.e., swimmersahead and behind) to avoid contact [8]. Thus, oneswimmer’s pace influences others; for example, if oneperson swims slowly, the swimmer behind is also forced toswim slowly to keep their distance. This changes theswimming pace of all swimmers sharing the lane.Therefore, swimmers choose different lanes according totheir skill levels and swimming speed [8].

The main concern of our game design is to balancedifferent fitness levels and workout goals; thus, weaugmented conventional group swimming in a virtualshared space [6]. Especially, the observation of ‘swimmingin a lane’ is analogous to the motion of linkedcompartments in a train; each compartment of the trainmust maintain an appropriate distance from adjacentcompartments to avoid collisions. Hence, we used a trainmetaphor that maps each swimmer to a compartment of avirtual train. In a virtual space, each swimmer maneuversa compartment using their own physical intensity.

In addition, we incorporated competitive and collaborativeaspects into the game for users’ enjoyment andengagement. SwimTrain is comprised of multiple rounds,with each round following the same three-part structure:a short competitive phase, called Compartment Ordering(see Figure 1); a longer collaborative phase, called TrainRunning (see Figure 2); and a short rest phase, calledTrain Stop (see Figure 3).

Compartment Ordering During this phase, eachswimmer’s current physical intensity is estimated andaggregated (e.g., mean intensity). The game determinesthe order of compartments with individual aggregatedintensities, and informs the players of the current orders(i.e., the rankings of swimmers). This competitive aspect

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promotes players’ engagement, and encourages higherintensity [9]. At the end of the phase, the aggregatedintensities of each swimmer becomes their target intensityfor the following phase, and they are given pointsaccording to their final rankings.

Water-proof earphones

Water-proof smartphone

with armband

Figure 4: A device setting forSwimTrain

Stroke Timing Swimming Style

GameHandler

NetworkManager

FeedbackManager

SwimmingActivities

Pressure Accel Gyro

Server

VibrotactileNarration

Spatial Earcon BGMs

LTE Network

Figure 5: An expected overallarchitecture of SwimTrain

Train Running The goal of this phase is for eachswimmer to continuously match their intensity with theirtarget intensity established in the Compartment Orderingphase. The difference between current and targetintensities for each swimmer shifts their compartmentaccordingly; a compartment shifts backwards when thecurrent intensity is lower than the target, and forwardswhen it is higher. In addition, a compartment collideswith an adjacent compartment if this difference exceedsan allowable range. Each swimmer’s game pointscorrespond to the length of time they go withoutcompartment collisions throughout the phase.

Train Stop In this phase, every swimmer takes a rest.The game determines total rankings of swimmers fromthe previous round by summing points of previous twophases (i.e., Compartment Ordering and Train Running).In addition, information about the next round, such as theduration of each phase and optional rules of the round isannounced to swimmers.

Furthermore, we incorporated some additional featuresinto the game. Swimmers can score bonus points if theyperform a given swimming style (i.e., freestyle, backstroke,butterfly, or breaststroke) throughout the round. We alsovaried the duration of each phase so that swimmers canapply different strategies to achieve a higher rank. Forexample, when the Compartment Ordering period islonger and the Train Running period is shorter, swimmersmight focus on the former period, even if they overexertthemselves. Both the target swimming style and thedurations for a round are announced during the TrainStop of the previous round. These features might provide

opportunities for unskilled swimmers to win the game.

Implementation ConsiderationTo play SwimTrain, we assumed that each swimmersecures a water-proof smartphone on their upper arm withan armband, and wears water-proof headphones (seeFigure 4). Swimming motions are recognized usingbuilt-in sensors of the smartphone, and the game’sprogress is delivered to users in forms of auditory andtactile feedback. Each device communicates with a serverusing LTE (Long Term Evolution) network, which is themost robust electromagnetic-based technology underwater [2]. An expected architecture of SwimTrain isshown in Figure 5.

As mentioned earlier, SwimTrain mainly uses physicalintensity as a game input. Previous work has suggestedheart rate to estimate physical intensity [7]. Instead, weconsidered the stroke rate (the number of strokes per unittime) as a measurement of a swimmer’s physical intensity,because an increase in stroke rate is correlated to anincrease in energy cost, which is defined as requiredenergy to move a unit distance for a unit mass body [3].To estimate the stroke rate, it is required to detect everysingle stroke timing. In addition, swimming styles shouldbe recognized to determine whether players areperforming the target swimming style throughout a round.We note that Choi et al. have suggested a real-timestroke detection module which recognizes stroke timingand swimming styles using an accelerometer, a gyroscope,and a barometer [2].

To inform players of the game’s progress and presence ofother players, we considered tactile feedback and a varietyof sound resources, such as spatial earcons, narrations,and background musics. For example, when a player isswimming slower than their own target intensities, thespatial earcon delivers warning signals that sound as if it iscoming from behind. An in-game narrator can also

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announce the situation (e.g., “You are too close to thecompartment behind”), and the game progress (e.g.,“Start the Train Running phase”). To help playersdistinguish phases, the game provides differentbackground music at each phase.

Future WorkWe are planning to implement a prototype of SwimTrainand conduct a user study iteratively. We will evaluatewhether our game design balances different fitness levelsand workout goals. For example, we can allow novices andcompetitive swimmers to play SwimTrain at the sametime, and investigate user experiences.

In addition, we will carefully consider the limitations ofhuman sensory capabilities during swimming. Our gameprovides a variety of sensory feedback, such as spatialearcons, narrations, and background music. However,swimmers’ compounded exhaustion may hinderrecognition of multiple feedback from the game [2]. Theymight also have difficulty distinguishing a direction of thespatial earcon, especially the front and the back [1].

We are also interested in applying our game design toother group fitness domains. Our train metaphor is basedon the observation of ‘swimming in a lane’, which canextend to ‘exercise in a line (or lane)’; for example,jogging or cycling in a line. We expect that such a groupfitness can be transformed into a SwimTrain-like game.

AcknowledgementsThis work was supported by the MSIP, Korea andMicrosoft Research, under IT/SW Creative researchprogram supervised by the NIPA(NIPA-2014-ITAH0510140110330001000100100).

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