Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> B. Types of Sports and Sportspeople <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> B. Types of Sports and Sportspeople <s> With this work we want to illustrate new ways to assist students during sports training and to enhance their learning experience. As an example, we present the design of a wearable system intended for snowboard training on the slope. The hardware platform consists of a custom-built sensor/actuator box and a mobile phone acting as host device. These devices run algorithms for activity, context, and mistake recognition, and trigger feedback in response to classification results. Instructors can use such a system to automatically supervise posture and motion of students, i.e., to detect common mistakes that are difficult to recognize when observing students from far away, and to provide immediate audible or tactile feedback for corrections during courses. The presented approach can further be applied to supervise posture and to alert users to potentially harmful body movements performed during daily physical activities. <s> BIB003 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> B. Types of Sports and Sportspeople <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> B. Types of Sports and Sportspeople <s> We developed a wearable device to improve lower limb sport training. The ::: presented system consists of a pair of spandex shorts which embed a processor ::: unit, 2 accelerometers and 2 vibro motors. The accelerometers are located in ::: proximity to the knees and measure tri-axial accelerations. We present a ::: novel method to compute and correct asymmetry of lower limbs during training. ::: The user performs an initial calibration phase which sets the accelerometer ::: reference frames. While running, the system continuously refines the ::: calibration using principal component analysis to take in account occasional ::: shorts assessments. The system activates a corrective vibro feedback on the ::: specific leg according to an asymmetry metric based on: (i) foot ground ::: impact, (ii) phase error between legs, (iii) transversal knee movements. User ::: tests demonstrated that the device is ergonomic to wear, easy to use and the ::: corrective vibro feedback is appreciated during the training. <s> BIB006 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> We present Cyclo, our prototype of a personal assistant for bike training using Google Glass. We describe our requirement study with 35 users and our design process for developing a novel application for Glass. Our hands-free user interface is potentially more convenient to use than traditional speedometers, and it provides instant performance feedback and context-aware notifications overlaid on the biker's view. <s> BIB007 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB008 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB009 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Persuasive technology to motivate healthy behavior is a growing area of research within HCI and ubiquitous computing. The emergence of commercial wearable devices for tracking health- and fitness-related activities arguably represents the first widespread adoption of dedicated ubiquitous persuasive technology. The recent ubiquity of commercial systems allows us to learn about their value and use in truly "in the wild" contexts and understand how practices evolve over long-term, naturalistic use. We present a study with 30 participants who had adopted wearable activity-tracking devices of their own volition and had continued to use them for between 3 and 54 months. The findings, which both support and contrast with those of previous research, paint a picture of the evolving benefits and practices surrounding these emerging technologies over long periods of use. They also serve as the basis for design implications for personal informatics technologies for long-term health and fitness support. <s> BIB010 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB011 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB012 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Wearable technologies are a growing industry with significant potential in different aspects of health and fitness. Gamification of health and fitness, on the other hand, has recently become a popular field of research. Accordingly, we believe that wearable devices have the potential to be utilized towards gamification of fitness and exercise. In this paper, we first review several popular activity tracking wearable devices, their characteristics and specifications, and their application programming interface (API) capabilities and availabilities, which will enable them to be employed by third party developers for the purpose at hand. The feasibility and potential advantages of utilizing wearables for gamification of health and fitness are then discussed. Finally, we develop a pilot prototype as a case-study for this concept, and perform preliminary user studies which will help further explore the proposed concept. <s> BIB013 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> The use of wearable technology will become significantly more prevalent in the coming years, with major companies releasing devices such as the Samsung Gear Fit. With sensors, such as pedometers and heart rate monitors, embedded in these devices it is possible to use them for fitness purposes. However, little is known about how wearable adopters actually use wearable and existing technologies during exercise. In an exploratory situated study of technology use and non-use in the context of the gym, fitness informatics adopters showed varied practices related to distraction, appropriating technology into their routines, and information needs. We discuss this variance in relation to individual differences and the impact of the physical nature of the gym. Although further research might show other influencing factors such as the social context, we make a case for the use of situated studies to uncover tensions that lead to use and non-use of technology that arise in the different unfolding situations of using wearables in everyday life, including at the gym, which is a surprisingly complex context. <s> BIB014 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> We have conducted interviews with ten elite and recreational athletes to understand their experiences and engagement with endurance sport and personal and wearable sports technology. The athletes emphasized the experiential aspects of doing sports and the notion of feeling was repeatedly used to talk about their activities. Technology played both an instrumental role in measuring performance and feeding bio-data back to them, and an experiential role in supporting and enhancing the sport experience. To guide further interaction design research in the sports domain, we suggest two interrelated ways of looking at sports performances and experiences, firstly through the notion of a measured sense of performance, and secondly as a lived-sense of performance. <s> BIB015 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Wearable fitness devices have demonstrated the capacity to improve overall physical activity, which can lead to physical and mental health improvements as well as quality of life gains. Although wheelchair athletes who participate in adaptive sports are interested in using wearable fitness trackers to capture their activity, we have observed low adoption of wearable fitness trackers among wheelchair athletes. We interviewed five wheelchair athletes and three physical and occupational therapists to explore fitness activities, experience with wearable technology, and potential uses for wearable fitness devices. None of the wheelchair athletes we interviewed had previously used any wearable fitness devices, however four out of five were interested in tracking their physical activity. We present five thematic areas helpful for thinking about wearable computing systems and accessibility challenges that arise based on incorrect assumptions about the athletic community. We highlight opportunities for improving the impact and accessibility of fitness tracking technologies for wheelchair athletes. These opportunities include improving the analysis of data from existing sensors, instrumenting the custom equipment used by adaptive sport athletes, and revising the language used in the presentation of fitness data to create a more inclusive community of users. <s> BIB016 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Recent years have been hailed by many as the era of the wearables. Meanwhile, gamification in the area of health and fitness has rapidly emerged as a popular field of research. This paper reports the early results of a long-term (70-day) study of using wearable activity trackers and gamification to promote exercise and being more active. The research is being conducted to investigate the motivational effects of using sensor- based games to promote daily exercise, as well as how different methods of releasing the application and its updated features may affect user's enthusiasm and the game's life-cycle. From the data we have collected so far, we can see the gradual emergence of clear pattern based on our periodically updated application. The initial results seem to support the notion of using gradual addition of features or changes as means of sustaining the participants' interest and usage. <s> BIB017 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB018 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB019 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB020 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> A longitudinal study in the real context of use of a wearable device, a sports watch, was conducted to understand how customization is used. For it, 103 users reported their device use in an online survey once a month for six months. Customization activity was found to be at its highest during the first months of usage. After six months of usage, 72% of the participants still used the customization options at least monthly, and of those, 23% customized weekly. Customization appears to be an important feature, as only 20% of the participants customized very little, and for some it was one of the reasons for their purchase decision. Overall, the majority (68%) were satisfied with the customization options on their sports watch. <s> BIB021 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Technological devices have evolved into a popular social trend becoming a part of many people's daily life. As a result, technology devices are becoming more commonly used for different tasks and activities. The current study examined if wearing a Nike Fuelband (FB) SE increased physical activity (PA) motivation for an adult population. The research design included an 8-week, pre-/post-test intervention. The inclusion of the FB SE served as the research intervention. Participants (n = 42) included two convenient samples located in Colorado and Nebraska. Prior to study investigation, participants were trained how to use all the functions of the device, associated Nike+ Connect program, and given additional resources for reference. Participants completed the Exercise Motivation Inventory-2 before device training and post 8 weeks. Pre- and post-data were analysed using a paired t-test. The current study reports that significant differences were present among the measured constructs of affiliation, enjoyment,... <s> BIB022 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Although studies have investigated how the technical features of wearable fitness trackers promote physical activity, we understand less about how communication surrounding such devices may contribute to their success. Addressing current opportunities for inquiry is important, as the popularity of fitness trackers and other wearable devices grows. Through interviews with 25 people wearing fitness devices, this study elucidates how and with whom people communicate fitness tracker messages and explains the effects of sociomaterial practice on interactions between wearable fitness device users. Our findings show the vital role of communication in sharing and encouraging physical activity. <s> BIB023 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> We proposed a new haptic instruction system for sports trainings that provides field players with instructed directions. The system consists of a stimulation unit (SU) for a player and an instruction unit (IU) for an instructor. Players wear the SU around their waist, and can recognize instructed directions by vibrations using 13 vibration actuators. The IU sends a direction where the joystick tilts to the SU via wireless communication modules. Preliminary experiments confirmed that the all participants did not feel the slipping away of the SU, and all participants were able to recognize its vibration even though they were running at 5, 10 km/h and standing (0 km/h). However, at 15 km/h, a participant who has a plump body recognized that a little or hardly recognized that at back part. We need to improve the method of providing stimuli at back part. By using the system, instructors and directors can provide the instructed directions to a field player without both any voice and gesture. <s> BIB024 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Collecting a digital footprint of data from one's everyday activities is becoming an information source for preventive health care. Wearable sensor technologies combined with mobile phone applications offer an interesting way to collect and monitor personal activity data for personal use, in addition to providing information for wellness and health care professionals. In this paper we present our service design approach for designing a mobile MyData Wellness concept that was developed for young athletes. The concept aims to combine different possibilities of mobile technologies to create a tool that can provide versatile support for wellness. The salient findings from the concept evaluation show that active young people find tracking sports data motivating and interesting, and call for a unified service that combines different wellness-related aspects of life. <s> BIB025 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Blindness dramatically limits quality of life of individuals and has profound implications for the person affected and the society as a whole. Physical mobility and exercises are strongly spurred within people, as ways to maintain health and well-being. Such activities can be really important for people with disability as well, and their increase is paramount in the well-being and assistive care system. In this work, we aim at improving the communication between the instructor and a visual impaired subject during skiing. Up to now, only the auditory channel is used to communicate basic commands to the skier. We introduce a novel use of haptic feedback in this context. In particular, the skier can receive directional information through two vibrating bracelets worn on the forearms. Haptic interaction has been proven to be processed faster by the brain demanding a less cognitive effort with respect to the auditory modality. The connection between the instructor and the skier is done by Bluetooth protocol. We tested different guiding modalities including only audio commands, audio and haptic commands and only haptic commands. Preliminary results on the use of the system reveled the haptic channel to be a promising way for guidance of blind people in winter sports. <s> BIB026 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB027 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> In this paper, we present a field study on the learning of climbing aimed at defining the design space of wearable devices to support beginners. Three main findings have emerged from our study. First, climbing has a strong emotional impact on beginners; therefore, learning to climb requires mastering new motor patterns as well as negative emotions, such as stress and fear. Second, the feeling of danger that climbers often experience can be mitigated by trust in the climbing partner and the perception of her active presence. Finally, a big problem in climbing is the communication difficulty between the climbing partners and between climber and instructor. We conclude the paper presenting four design considerations for the design of wearable devices meant to support the learning of climbing by providing the actors involved with augmented communication. Such augmented communication should address both the physical and the emotional difficulties of this sport. <s> BIB028 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Winter sports like skiing and snowboarding are often group activities. Groups of skiers and snowboarders traditionally use paper maps or board-mounted larger-scale maps near ski lifts to aid decision making: which slope to take next, where to have lunch, or what hazards to avoid when going off-piste. To enrich those static maps with personal content (e.g., pictures, prior routes taken, or hazards encountered), we developed SkiAR - a wearable augmented reality system that allows groups of skiers and snowboarders to share such content on a printed panoramic resort map. The contribution of our work is twofold: (1) we developed a system that offers a novel way to review and share personal content in situ while on the slope using a resort map; (2) we report on the results from a qualitative analysis of two user studies to inform the design and validate the usability and perceived usefulness of our prototype. <s> BIB029 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB030 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB031 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Most interactive sports-oriented products that are commercially available focus on individual athletes. The ones that focus on team sports rarely go beyond performance monitoring. Therefore, in this case study we focus on team dynamics in secondary school sports teams. These teams typically have to deal with unbalanced engagement due to skill level differences. This can impede the goals of these PE-classes; to raise young people's enthusiasm for a variety of sports and to teach them how to work together as a team. In this project we explore a design solution aimed at balancing engagement in these mixed level sports teams, through an intelligent system of connected light jerseys. The jerseys, iteratively developed through experiential prototypes that were used during secondary school basketball games, were able to measure ball possession and give feedback through a series of light stripes. In this paper we describe two iterations of this case study and our quantitative and qualitative findings of team engagement. <s> BIB032 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB033 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Many people who are blind or partially blind continue to enjoy alpine sports such as skiing and snowboarding. Because of their restricted visual perception, visually impaired (VI) skiers are usually accompanied by a ski guide. We present VIHapp, a system consisting of smart ski poles, smart armbands and an instrumented ski to enable communication between VI skiers and ski guides. Guides send commands to VI skiers by pressing a button on their ski poles. VI skiers receive commands in the form of vibrations on their armbands. The smart ski detects turns performed by VI skiers and sends notifications to the guide's smart ski poles. <s> BIB034 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB035 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> We introduce Goby, a swimming aid that provides audio feedback for blind and visually impaired athletes. Goby's activity tracker is worn on the thigh and uses a downward-facing camera to track the swimmer's position in the pool. Goby detects when the user is swimming outside the lane or approaching a wall, and warns the user via an audio notification. In this paper, we introduce the Goby prototype and share formative feedback about the prototype from blind and sighted swimmers. <s> BIB036 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB037 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <s> Tai-Chi Chuan (TCC) is a famous physical exercise and well-known for being able to effectively promote physical well-being. Many people have been interested in learning TCC at the beginning, but eventually failed in mastering it due to the lack of a constantly accompanying master on the side. In this paper, we present an augmented-learning tool, called "My Tai-Chi Coaches", for learning TCC. By wearing an optical see-through Head-Mounted Display (HMD), the users can have their own private coaches-on-demand that will guide them in practicing TCC. To solve the "attention-sticking" problem, we propose the use of "redundant coaches" and high-lighting the primary coach at every instant. When the user wants to adjust his posture to mimic the coach's movement, he can simply suspend his motion, and then the drone will fly to a proper position to capture the images of the user's posture, and display them on an augmented mirror placed near by the highlighted or gazed coach. In addition to learning TCC, the proposed augmented-learning tool can also be used for learning dancing, yoga, sporting, and for rehabilitation. <s> BIB038 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB039 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB040 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> B. Types of Sports and Sportspeople <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> BIB041
The types of sports and sportspeople addressed in our corpus vary considerably, even though regularities are present. Nine papers do not focus on a specific sport but rather consider sports in a very generic way BIB017 , BIB018 , BIB004 , BIB019 , BIB020 , BIB021 , BIB040 - BIB012 . Seven papers refer to fitness BIB013 , BIB022 , BIB010 ,  - BIB023 , BIB014 . Six papers point to broad categories of sports such as lower limb sports BIB006 , endurance sports BIB015 , strategic sports BIB031 , field sports BIB024 , Olympic sports  , or wheelchair sports BIB016 . The remaining ones address a wide range of different sports: eight are on skiing/snowboarding, seven are on running, and four papers focus on climbing. Sports such as cycling, tennis, swimming, and martial arts are only investigated in two papers each. Finally, other sports addressed (each one mentioned in one paper only) are diving, roller derby, rowing, badminton, and weightlifting. Only three team sports are present in our corpus: basketball BIB032 , football BIB033 , and hockey BIB025 . No paper considers motor sports such as car or motorcycle racing. See Fig. 1 for an overview of the sports addressed in the corpus. For what concerns the targeted users, most papers (27 out of 57) focus on generic sportspeople (e.g., without specifying their level of expertise, such as beginner or elite, or referring to a generic practitioner). Two papers address disabled sportspeople, without specifying their level of expertise BIB026 , BIB034 . Five papers consider elite athletes BIB002 , BIB027 , BIB025 , BIB041 , BIB035 and two impaired elite athletes BIB036 , BIB016 . Three papers consider both elite and amateur sportspeople BIB007 , BIB040 , BIB015 , and three amateur sportspeople only BIB008 - BIB003 . Beginners are investigated in 11 papers, e.g., BIB011 - BIB009 , BIB028 , BIB005 . It is worth noticing that among the papers addressing beginners, three are focused on climbing (out of a total of four papers addressing climbing). Probably, this is due to the fact that some sports (e.g., climbing) need a higher technical expertise to be practiced than other sports (e.g., running), thus requiring research on technology capable of supporting novice athletes. Four papers do not investigate sportspeople directly, but target audience of sports events BIB004 , BIB033 ,  , BIB037 . Other sports actors, such as coaches, teammates, judges, therapists, and social network audience, are also mentioned in our corpus (19 papers out of 57), highlighting the social dimension of sports. Health professionals occur twice BIB016 , BIB025 . Coaches are considered in eight papers BIB026 , BIB024 , BIB034 , BIB027 , BIB038 , BIB001 , BIB028 , BIB041 , sports partners, and teammates are investigated five times BIB029 - BIB030 , BIB031 , BIB032 , whereas judges are mentioned only in BIB002 . Finally, social network audience is considered in three works BIB039 , BIB023 , BIB012 .