Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> The Hummingbird is a wearable computer that aims to support communication in co-located groups of people, by giving users a continuous awareness of the physical presence (or absence) of others. To examine the effect on group communication, we performed a study where six ski instructors used the Hummingbirds during a five-day trip. The study showed that the Hummingbirds were used more as a support for informal social interaction than for the actual work activities of the test group. In subsequent focus group sessions, we saw a clear difference between instructors who had used the devices and those who had not, in that the first group gave many enthusiastic suggestions for improvements and new usage areas, whereas the second group had great difficulties in seeing any use for the devices at all. <s> BIB001 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Ubiquitous and Wearable Computing both have the goal of pushing the computer into the background, supporting all kinds of human activities. Application areas include areas such as everyday environments (e.g. clothing, home, office), promoting new forms of creative learning via physical/virtual objects, and new tools for interactive design. In this paper, we thrust ubiquitous computing into the extremely hostile environment of the sparring ring of a martial art competition. Our system uses piezoelectric force sensors that transmit signals wirelessly to enable the detection of when a significant impact has been delivered to a competitor's body. The objective is to support the judges in scoring the sparring matches accurately, while preserving the goal of merging and blending into the background of the activity. The system therefore must take into account of the rules of the game, be responsive in real-time asynchronously, and often cope with untrained operators of the system. We present a pilot study of the finished prototype and detail our experience. <s> BIB002 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Studying sport in the academia has been in existence for several decades. The educational pursuits in sport have been rooted in such disciplines as history, management, sociology, marketing, organisational behaviour, and law. Communication is another of these established academic disciplines upon which the study of sport has been juxtaposed. One way for the intersection of sport and communication - sport communication - to continue to grow as its own academic discipline is through defining the field itself. Therefore, this analysis proposes a unified definition for the academic study of sport communication and examines the unique and integrated elements involved. Such a definitional inquiry assists in the development of the disciplinary parameters and research possibilities of the field of sport communication. <s> BIB003 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> We present a novel concept for an audience voting system for judged sports events. It is based on wireless wearable motion sensors utilizing the natural behaviour of sports spectators -clapping and cheering. This paper describes initial results from a user study that guided our design process. We further present two preliminary prototypes focusing on hardware and design feasibility respectively. Results confirm our assumption that the system does not provide objective results, but has the potential to increase the spectator experience by giving audience members the feeling of being part of the voting process. <s> BIB004 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> We describe a user study investigating how a wearable training system for rowing should look like. The study covers all design stages from initial observations up to mockup user tests. In contrast to other work concentrating mainly on professional rowers, we target the much larger group of beginners. For our study we had a test group of 80 students and instructors who were observed for 25 hours, went through interviews lasting more than 17 hours in total and spent 30 hours refining and testing the concept. <s> BIB005 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> This paper offers guidance to conducting a rigorous literature review. We present this in the form of a five-stage process in which we use Grounded Theory as a method. We first probe the guidelines explicated by Webster and Watson, and then we show the added value of Grounded Theory for rigorously analyzing a carefully chosen set of studies; it assures solidly legitimized, in-depth analyses of empirical facts and related insights. This includes, the emergence of new themes, issues and opportunities; interrelationships and dependencies in or beyond a particular area; as well as inconsistencies. If carried out meticulously, reviewing a well-carved out piece of literature by following this guide is likely to lead to more integrated and fruitful theory emergence, something that would enrich many fields in the social sciences. <s> BIB006 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> In recent years the sport of climbing has seen consistent increase in popularity. Climbing requires a complex skill set for successful and safe exercising. While elite climbers receive intensive expert coaching to refine this skill set, this progression approach is not viable for the amateur population. We have developed ClimbAX - a climbing performance analysis system that aims for replicating expert assessments and thus represents a first step towards an automatic coaching system for climbing enthusiasts. Through an accelerometer based wearable sensing platform, climber's movements are captured. An automatic analysis procedure detects climbing sessions and moves, which form the basis for subsequent performance assessment. The assessment parameters are derived from sports science literature and include: power, control, stability, speed. ClimbAX was evaluated in a large case study with 53 climbers under competition settings. We report a strong correlation between predicted scores and official competition results, which demonstrate the effectiveness of our automatic skill assessment system. <s> BIB007 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Abstract Running is one of the most popular sports for the masses. However, not every runner might run properly. Incorrect running technique decreases movement efficiency and increases the risk of injury. In this work, we present the development of a smartphone application to provide feedback on running technique on the example of arm carriage. Recognition algorithms were developed in a preliminary study with 10 participants. Investigating sensor positions and modalities, we found that a single IMU on the upper arm yielded an accuracy of 80.73% for the assessment of arm movement. We implemented our approach as a smartphone application and found that runners improved their arm movement using our application within a user study including 23 participants. Results from questionnaires revealed high user acceptance (average rating of 8 from 10 possible points). <s> BIB008 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Marathon is very popular in recent years. However, finishing the game is no easy task, especially for beginners. Regular practices and training are needed. With the availability of wearable devices, it is possible to develop virtual coaches that monitor the progresses of individual runners closeup and guide them through tailor-made training schedules. Unfortunately, most existing wearable devices only record physiological signals of the runners and rely on off-line processing to provide feedbacks. In this paper, we present the design and development of an on-line virtual coach, which performs real-time tracking and analysis of the physiological status of the runner and suggests appropriate adjustments on the exercise intensity. The proposed virtual coach is a pure software solution and can work with any wearable device that monitors the heart rate and running speed of the runner. The main challenge of our system is to predict when the runner will reach the various running states and instruct the runner to adjust the speed just ahead of time so that her/his body can react in time to maintain the required training intensity. Experiments on real users show that our proposed algorithms can correctly predict the running states of the runners and help them to better maintain the required intensity to maximize the training effects. <s> BIB009 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> This article focuses on the practice of self-tracking of physical activity data and sharing it via social networking sites. The use of wearable technology devices and the latest smartphones with built-in GPS tracking technology - capturing the speed, distance and duration of physical activities such as running and cycling - is a striking example of the trend towards quantifying sports performances. The study explores the determinants and motivations of recreational athletes to share physical activity status updates on the social networking sites Facebook and Twitter. Evidence is drawn from a large-scale survey of 400 users of Strava, a popular fitness app and online community. The results suggest that intrinsic rather than extrinsic motivations determine a person's willingness to share physical activity via social networking sites. <s> BIB010 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Recent advances in technology fostered the commercialization and usage of wearable devices. Among diverse form factors, wrist worn devices stand out. Benefitting from a conventional format and easy access, wrist worn devices, such as smart watches and fitness trackers, have been gaining popularity. While their continuous usage and close contact with the human body enable various applications, their limited computational resources summed with continuous changes in the context of use challenge designers in providing effective interactive solutions for end users. Seeking to understand how the context of use impacts the user experience and interaction with ten popular wrist worn wearables, in this study we analyzed the users' feedback: 545 users' comments were collected from Amazon, coded and aggregated. Based on the users' feedback, we identify 31 major problems that are currently faced in wrist worn interfaces. The analyses of the users' feedback led to a discussion about the causes and severity of those problems, and also to the definition of a set of design implications aimed at improving the user interaction with the next-generation wrist worn wearables. <s> BIB011 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> The ClimbingAssist supports beginners in improving their technique. It uses a pressure sensitive foil on an insole and gives direct feedback while climbing depending on the pressure on the foot and the movement speed. We evaluated our design in a study in a climbing gym. <s> BIB012 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> The use of external motion sensors with the athletes' wearables will enable new advanced applications for providing feedback on movement. We show how visual 3D-feedback based on Inertial Measurement Units (IMU) is technically and conceptually feasible. Our wearable-app connects to our custom designed IMU-pods for measuring the legs' orientation. The App then shows an animated kinematic model in 3D. Our study with ten runners further contributes by providing first insights into how to apply natural, live-feedback with wearables for supporting run-training. Our prototype for the smartphone and head-up display demonstrates great potential for personal- and everyday use. <s> BIB013 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Research into the kinematic training of elite divers shows a demand for diver training using biomechanical feedback. With suitable inertial data and tactile feedback, divers and their coaches could better understand their dives and failure modes. This would help improve technique and reduce fatigue during both training and competition, resulting in higher quality dives. We developed the Diving Coach Monitor (DCM) that can wire-lessly stream inertial data to an assistant as well as vibrotactially signal an athlete during a dive. The DCM is comprised of a wearable sensor module, worn by a diver and a smartphone application for the diver's coach. The diver's coach uses the smartphone application to signal the wearable sensor module, throughout the training session. The wearable sensor module receives the control commands and acts accordingly with one of the following actions: vibrate (to signal the diver); commence inertial data sampling; stop inertial data sampling and transmit data back to the smartphone application. While the DCM is water-proof, we trialled the DCM in a “dry-land” environment, as divers often train with trampoline spotting rigs and (occasionally) a safety harness. We also conducted multiple trial sessions with circus and gymnastic aerial apparatus and athletes. Our tests showed accurate measurement and low latency compared to video motion analysis. <s> BIB014 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Cycling is a popular sport in which assistance devices are used for measuring heart rate, speed or cadence. Even if much more important than performance metrics, systems for supporting communication within the group are not available. Speech and standard hand-gestures are commonly used by cyclists to communicate danger and to propagate commands from the front to the end of the group. We propose an approach to enhance the communication chain by using gesture recognition and LEDs sewed into the backside of the cyclists' shirts. We studied the requirements for using the system for augmenting gestures with light, by presenting our prototype to a group of cyclists asking for their opinion. We found that about half of the cyclists fear new irritations, but most of the cyclists would also appreciate the support, especially for supporting large groups. <s> BIB015 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> The interest in virtual and augmented reality exploded during the last two years. We propose the use of these systems in the field of sports by combining this technology with a local area radio-based localization technology. This allows for novel application scenarios using virtual environments in team-based sports, which are outlined in this work. We conducted an online survey among 227 athletes about the acceptance of virtual reality headsets for training in different kind of sport disciplines. <s> BIB016 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Abstract There has been a market surge in both provision of and demand for fitness applications and sport wearables. These wearables often come equipped with highly sophisticated biometric data (e.g. heart rate) functionalities that make the capture and sharing of such biometric data increasingly common practice. A few research studies have considered the effect that sharing biometric data has on those individuals sharing this data. However, little is known regarding the social impact of sharing this data in real-time and online. In this study, we investigate whether there is value in sharing heart rate data within social applications and whether sharing this data influences the behavior of those seeing this data. We do so by conducting a study where the heart rate data of runners competing in a 5-km road race is shared in real-time with 140 online spectators. We collect rich quantitative data of user interaction though server logs, and a qualitative data set through interviews and online users' comments. We then compare and contrast the behavior of online spectators who are presented with heart rate data together with contextual data, and those who are only presented with contextual data, for example, location. We also examine whether this difference is dependent on the social relation between the athletes and the spectators. Results indicate that spectators who are presented with the runners' heart rate data support the athletes more and rate the presented system more positively. These effects are dependent on the social tie between the athletes and spectators. This is one of the first studies to carry out an empirical investigation in the wild on the effects of sharing heart rate data in an online social context. In this light, in addition to supporting earlier literature, the outcomes present new insights and research directions within the sporting context. <s> BIB017 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> The rise of mobile technology has transformed the once passive activity of watching a live sports broadcast into an active experience. Nowadays, it is common practice for sports fans to communicate, interact and share information with others through social mobile applications not only after, but also during the broadcast of a live sport event. However, sometimes the discussion between fans is not contextualised and the social applications used by them lack tools to register moments that can promote social discussions. Furthermore, not all sports fans can watch an event TV broadcast, making it impossible to express a concrete opinion about it. To address this issue, we developed ReactIt, a system developed for smartphones and smartwatches, that allows users to share automatically generated videos containing specific moments of a football match along with their emotional reaction, to engage fans and promote social interaction between them. Results from user tests were very positive regarding the interaction with both devices, and users manifested great interest in using ReactIt in a real life environment. <s> BIB018 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> In running, knee-related injuries are very common. The main cause are high impact forces when striking the ground with the heel first. Mid- or forefoot running is generally known to reduce impact loads and to be a more efficient running style. In this paper, we introduce a wearable running assistant, consisting of an electrical muscle stimulation (EMS) device and an insole with force sensing resistors. It detects heel striking and actuates the calf muscles during the flight phase to control the foot angle before landing. We conducted a user study, in which we compared the classical coaching approach using slow motion video analysis as a terminal feedback to our proposed real-time EMS feedback. The results show that EMS actuation significantly outperforms traditional coaching, i.e., a decreased average heel striking rate, when using the system. As an implication, EMS feedback can generally be beneficial for the motor learning of complex, repetitive movements. <s> BIB019 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> A large number of activity-tracking devices have recently dominated the fitness world. These devices typically track different forms of activities and are argued to encourage more active lifestyles. The devices encourage and incentivize change in behavior through mechanisms including personal goals, gratifying representations, and social features. However, both current research and anecdotal evidence about the real impacts of these devices point to mixed outcomes. Many users enjoy positive experiences, while others are reported to have abandoned these devices without generating lasting value for themselves. Through a qualitative study of 29 users of Fitbit activity-tracking devices, we explore how different types of pre-existing motivation shaped people's perception and adoption of the device. Building from the affordance perspective, our findings suggest that users' pre-existing motivations, derived from unique life priorities, personal situations, and personalities, may interact with different aspects of the tool, and result in disparate outcomes. Two primary conclusions of this research are (1) the motivational features of activity-tracking devices may only complement already existing motivations of the users but do not create incentive for more physical activities on their own. (2) The value of informational affordances of activity trackers diminishes over time for most users (except the quantified selfers), and without motivational affordances, informational affordances do not sustain long-term use of the device. <s> BIB020 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Wearable smart devices enhance athletes' physical activities by providing physical data on their performances. However, there is a high abandonment rate regarding these devices. This study aims to understand the habits and the wishes of the tennis players in order to create a more prolonged and frequent wearable usage. As a preliminary work, we conducted an online survey on the Turkish Tennis Federation's website with 1567 participants. Later we conducted in-depth interviews with 20 professional and international tennis players to get a better understanding of their wishes. Our initial results suggest that with the increase of tennis playing frequency the wearable usage frequency increases, which has not been indicated by previous studies. However, the most striking outcome of the study is the tennis players' need for feedback regarding mental states, which should be considered for future wearables. <s> BIB021 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> The last two decades have seen growing interest in promoting physical activities by using self-tracking technologies. Previous work has identified social interactions in self-tracking as a crucial factor in motivating users to exercise. However, it is unclear how integrating fitness features into complex pre-existing social network affects users' fitness tracking practices and social interactions. In this research, we address this gap through a qualitative study of 32 users of WeRun--a fitness plugin of the widely adopted Chinese mobile social networking service WeChat. Our findings indicate that sharing fitness data with pre-existing social networks motivates users to continue self-tracking and enhances their existing social relationships. Nevertheless, users' concerns about their online personal images lead to challenges around privacy. We discuss how our study could advance understanding of the effects of fitness applications built on top of pre-existing social networks. We present implications for future social fitness applications design. <s> BIB022 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> We present JackIn Airsoft, a system for generating maps for multi-player sport activities and sharing their first-person views (FPVs). In first-person shooting (FPS) games, maps are generated for the visualization of the player's location; these maps are used for strategic play and discussions. FPS games are a virtual experience of shooting or of military activities; the displaying of maps on a screen is a technique designed for game playing. We address the challenge of adapting this effective map visualization technique to real-world strategic sports. In this paper, we introduce our prototype map generator for airsoft sports that is based on the usage of wearable cameras and simultaneous localization and mapping (SLAM). The system enables users to switch between the FPV and the generated map in order to share a player's experience and a strategic overview for team sports. We applied ORB-SLAM2 to multiple recorded FPV videos to discuss the situations and conditions appropriate for our system. <s> BIB023 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> The growing popularity of winter sports, as well as the trend towards high speed carving skis, have increased the risk of accidents on today's ski slopes. While many skiers now wear ski helmets, their bulk might in turn lower skiers' ability to sense their surroundings, potentially leading to dangerous situations. In this paper, we describe our "Smart" Ski Helmet (S-SH) prototype. S-SH uses a set of laser range finders mounted on the back to detect skiers approaching from behind and warns the wearer about potential collisions using three LEDs mounted at the helmet's front edge, slightly above the wearer's eye level. In this work, we describe a controlled experiment with 20 ski and snowboarding enthusiasts and a follow-up on-slope deployment with 6 additional participants of varying levels of expertise. Our findings indicate that the S-SH can significantly increase skiers' peripheral perception on traverse trails. <s> BIB024 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Purpose ::: ::: ::: ::: ::: This paper aims to analyse the adoption of fitness wearables by using the unified theory of acceptance and use of technology (UTAUT). The study analyses the relative weights and causal combinations of antecedent variables on use and intention to use fitness wearables. ::: ::: ::: ::: ::: Design/methodology/approach ::: ::: ::: ::: ::: The study design involves two stages: first, from the perspective of variable-oriented analysis, a structural equation model is tested using partial least squares (PLS) technique on a sample of 176 adopters and a second sample of 187 non-adopters. Second, from the perspective of case-oriented analysis, a fuzzy set qualitative comparative analysis (fsQCA) identifies causal combinations of variables that lead to use of wearables by adopters and intention to use by non-adopters. ::: ::: ::: ::: ::: Findings ::: ::: ::: ::: ::: PLS results show that performance expectancy and effort expectancy have high net effects on use and intention to use for adopters. FsQCA analysis shows that current users follow a streamlined path to adoption. High beliefs on performance expectancy and effort expectancy are the main influences of intention to use a fitness wearable for non-adopters. In contrast to adopters, non-adopters may follow a number of paths to intention to use through performance expectancy, effort expectancy or facilitating conditions. This insight was apparent only after analysing the data sets by using fsQCA. ::: ::: ::: ::: ::: Research limitations/implications ::: ::: ::: ::: ::: For sake of parsimony, this paper tested UTAUT model instead of the more complex unified theory of acceptance and use of technology 2. ::: ::: ::: ::: ::: Practical implications ::: ::: ::: ::: ::: Marketers in the fitness category can enhance use and intention to use by utilising not one but a combination of causal factors such as performance expectancy, effort expectancy and facilitating conditions. Wide societal deployment of wearables depends on performance and expectations. ::: ::: ::: ::: ::: Social implications ::: ::: ::: ::: ::: The widespread use of mobile devices depends on performance expectancy and effort expectancy. To transit to a real knowledge economy, co-creation should occur at early stages of product development so that these expectations are shared and better products be developed. ::: ::: ::: ::: ::: Originality/value ::: ::: ::: ::: ::: This paper offers a nuanced understanding of fitness wearable adoption by analysing adopters and non-adopters through variable- and case-oriented techniques. It complements the one-linear-path perspective with a number of alternative causal combinations of variables that lead to use and intention to use fitness wearables. While the causal path for adopters is unique, there are a number of causal combinations of antecedents that lead to high intention to use in potential adopters. <s> BIB025 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Technological advances in wearable computing are changing the sports domain. A variety of Personal Informatics (PI) tools are starting to provide support and improve athletes’ performance in many sports. In this article, we interviewed 20 amateur and elite athletes of different disciplines, using an array of PI devices, to explore how sports, as well as athletes’ experience, are affected by such instruments. We discovered that amateur athletes present different patterns of usage compared to elite ones. Moreover, we found that elite athletes make sense of their data by exploiting the knowledge they have about their own body and sports practice. We then proposed four considerations for design that we believe should be explored in the future, to reflect on how self-tracking is changing our perspective on sports, and, by and large, on our everyday life. <s> BIB026 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> C. Role of Wearable Devices in Sports <s> Flow state is a psychological state of optimal performance. To experience flow state, one needs to receive unambiguous feedback. Previous studies have described activities with internalized feedback modalities (e.g. visual). However, they do not offer any appropriate feedback modality for the activities that may benefit from external feedback, such as opponent-based sports. Addressing the issue, we adopted a research through design process and considered tennis as our case, in which players can benefit from attaining flow [1]. This pictorial reveals our approach to design 6 wearable device concepts under 3 design themes as future directions for design practitioners and researchers. <s> BIB027
We identified three nonexclusive roles that wearables may play in the sports practice, namely, enabling, improving, and augmenting one or more sport-related aspects. Enabling means that wearables allow users to do something that would be impossible to do without technology; improving means that wearables are meant to support the user in doing something in a better way; augmenting relates to do something in a different way than how it was done without technology. In order to analyze the kind of support given by technology, we distinguished three aspects of the sports practice, namely the physical, the cognitive-emotional, and the social aspects. 1) Physical: It relates to performance and motor skills acquisition for specific sports techniques; while the former is generally a concern for experienced athletes, the latter pertains mainly to beginners. In sports, a good technique means how well a skill is performed, whereby a skill is an achieved ability to bring about predetermined results, with a maximum of certainty and often with the minimum of outlay time, energy, or both  , for example, the correct use of feet in climbing. 2) Cognitive-emotional: It comprises emotions, flow, mental control, and other psychological factors such as motivation, i.e., the promotion of the desire or willingness to do or achieve something. Motivation is important in sport: It can be defined as the direction (i.e., the situations, practices, etc., to which an athlete is attracted) and intensity (i.e., how hard she tries) of one's effort, whereby the temporal dimension is relevant, i.e., how sustained or lasting that effort is  . 3) Social: It encompasses the broad dimension of social relations and inclusiveness; it refers to activities that allow people to meet each other for pleasure. It also concerns interpersonal and organizational communication, both verbal and nonverbal BIB003 . As summarized in Table II , the main role emerging from our corpus is to improve a specific sports aspect (30 papers), while few papers aim to enable BIB006 or augment (9) a sport. It is worth noticing that some papers could be classified into multiple categories as they address more than one aspect of sports: however, for the sake of clarity, we considered only the main role, i.e., the role that is more extensively discussed in the paper. Three papers were not classified with reference to the role of wearable BIB011 ,  , BIB025 . Moreover, we could not identify any example in which technology was meant to enable the cognitive-emotional aspect. As for the enabling role, 15 papers either support the acquisition of motor skills by beginners or allow impaired individuals to practice a sport. Franke and Lukowicz BIB005 provide rowing beginners with a system that allows to both train and monitor their technique without requiring the direct supervision of an instructor. Feeken et al. BIB012 design a wearable system that facilitates the development of technical skills of beginner climbers. Chen et al. BIB009 develop a virtual coach that helps marathon beginners adjust their speed based on their heart rate so that their body can react in time to maintain the required training intensity. Three papers focus on enabling the social experience  , BIB017 , BIB018 : They present tools for making the enthusiasm of remote audience visible in order to enable the public's participation during sports events. The improving role is the most frequently discussed role in our corpus, being present in 30 papers. A total of 14 papers focus on improving the physical aspect of sports. For example, Ladha et al. BIB007 propose a performance analysis system that replicates expert assessments, thus representing a first step toward an automatic coaching system for climbing. Hassan et al. BIB019 , Seuter et al. BIB013 , and Strohrmann et al. BIB008 propose systems based on different types of feedback to improve the performance in run training. Chi et al. BIB002 aim to better the judges' performance assessment, giving help in evaluating sparring matches in martial arts. Rapp and Tirabeni BIB026 explore how wearables impact on the athlete's performance, finding that their effect may change depending on her level of experience. A total of 11 papers focus on the improvement of the cognitive-emotional aspects of sports. Kidman et al. BIB014 , for instance, aim to ameliorate the athletes' self-awareness of both short-and long-term fatigue in order to control task execution consciously. Jarrahi et al. BIB020 investigate the impact that wearables have in motivating people to do physical activity. Havlucu et al. BIB027 , BIB021 highlight the importance of flow in the sports performance of tennis players and propose concepts that help to maintain it. Five papers focus on aspects related to the social experience: For example, Kraeuter et al. BIB015 propose a system using gesture recognition and a series of light emitting diodes (LEDs) sewed on the back of cyclists' shirt in order to help them communicate when they are on the road, thus improving interpersonal communication. Gui et al. BIB022 and Stragier et al. BIB010 investigate the impact of sharing information about sports activity on social networks. The augmenting role is the less discussed role in our corpus. This group includes nine works introducing interactive elements into the sports activity so that the nature of the sport itself is modified (e.g., in its rules and objectives). Three papers focus on augmenting the social experience. Tomitsch et al. BIB004 use wireless wearable motion sensors to augment spectator participation in loco, changing their opportunities for intervening. Weilenmann et al. BIB001 and Kono et al. BIB023 present wearable systems for augmenting the social experience of groups of collocated sportspeople. The augmentation of the physical aspects of sports is addressed only by Niforatos et al. BIB024 , who developed a system for augmenting the skiers' peripheral view, allowing them to perceive whether somebody is getting to their back. Five papers present devices that aim to augment cognitive-emotional aspects: For example, Colley et al.  investigate the effects of presenting on a head-mounted display (HMD) an alternative virtual reality (VR) view while the skier is on a real slope, creating a blended virtual/real experience, whereas Gradl et al. BIB016 explore the acceptance of VR and AR systems among athletes.