Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB001 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB002 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <s> Modern roller derby is a predominately female driven full contact sport. A relatively new and evolving sport, players are yet to benefit from recent advances in wearable technologies. This paper reports on our initial investigations into player attitudes towards the use of technology as a training aid. Our survey results highlight broad support for the development of a wearable training device. Over 300 participants identified the skills they want help with improving and provided some initial feedback on the appropriateness of feedback modalities and location of a wearable training device. We end the paper by introducing our first interaction prototype, TapTrain, that allows skaters to access feedback on their technique while skating. <s> BIB003 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB004 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <s> Group exercise has multiple benefits including greater adherence to fitness regimens, increased enjoyment among participants, and enhanced workout intensity. While a large number of technology tools have emerged to support real-time feedback of individual performance, tools to support group fitness are limited. In this paper, we present a set of wearable e-textile displays for running groups called Social Fabric Fitness (SFF). SFF provides a glanceable, shared screen on the back of the wearer's shirt to increase awareness and motivation of group fitness performance. We discuss parallel prototyping of three designs-one flexible e-ink and two flexible LED-based displays; the selection and refinement of one design; and two evaluations'a field study of 10 running groups and two case studies of running races. Our qualitative findings indicate that SFF improves awareness of individual and group performance, helps groups stay together, and improves in-situ motivation. We close with reflections for future athletic e-textile displays. <s> BIB005 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB006 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB007 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB008 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB009 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB010 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB011 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <s> Wearable sports devices like GPS watches and heart rate monitors are ubiquitous in sports like running or road cycling and enable the users to receive real-time performance feedback. Although rock climbing is a trending sport, there are little to no consumer electronics available to support rock climbing training during exercise. In this paper, we investigated the acceptance and appropriateness of wearables in climbing on different body parts. Based on an online survey with 54 climbers, we designed a wearable device and conducted a perception study with 12 participants in a climbing gym. Using vibro-tactile, audible, and visual cues while climbing an easy route and a hard route, requiring high physical and cognitive load, we found that the most suited notification channel is sound, directly followed by vibro-tactile output. Light has been found to be inappropriate for the use in the sport of climbing. <s> BIB012 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB013 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB014 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB015 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB016 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB017 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB018 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB019 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB020 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB021 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB022 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <s> Mobile technologies have become an important part of run training, however, existing technologies focus on performance metrics (e.g., distance and pace), which makes it difficult for runners to improve their running technique. In this paper, we present Strive, a wearable running technology that aims to assist runners in achieving rhythmic breathing; a running technique that potentially leads to improved results and lower injury risk. Strive continuously collects physiological data and uses haptic feedback to provide real-time assistance during runs. As communicating technique-related information in the dynamic and complex context of a run is challenging, we present two studies. The first study investigates how runners adapt to two different vibration patterns; and the second study explores the temporality of the assistance through three different approaches: Continuous, periodical, and self-serviced. Based on these studies, we discuss and provide insights on interacting with technologies during runs. <s> BIB023 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB024 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB025 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB026 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB027 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB028 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB029 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <s> While wearable devices for fitness have gained broad popularity, most are focused on tracking general activity types rather than correcting exercise forms, which is extremely important for weightlifters. We interviewed 7 frequent gym-goers about their opinions and expectations for feedback from wearable devices for weightlifting. We describe their desired feedback, and how their expectations and concerns could be balanced in future wearable fitness technologies. <s> BIB030 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB031 </s> Designing Wearable Systems for Sports: A Review of Trends and Opportunities in Human–Computer Interaction <s> A. Research Perspectives and Methodological Approaches <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> BIB032
We recognized three different research perspectives in our corpus: the technology-driven, the design-driven, and the acceptance study perspective. The technology-driven perspective consists in the presentation and discussion of novel devices (usually prototypes) in a specific sports context. Papers adopting this perspective focus on the potentialities of a specific technological solution: the design idea is often presented in terms of requirements and the motivation for its development is commonly taken from the literature. These studies present user evaluations, albeit only preliminary, revolving around usability aspects. We identified 31 papers belonging to this perspective BIB011 - BIB023 . The design-driven perspective includes ten papers BIB003 - BIB012 . This perspective focuses on design aspects and often employs a constructivist stance, involving potential users in validating the proposed design idea. Two papers use a research-through-design approach BIB024 , BIB029 , while one employs design workshop activities BIB013 . One paper uses interviews with potential users BIB030 , one adopts observation and semistructured interviews BIB014 , and one employs content analysis of online reviews of wearable devices BIB015 . Others engage users through questionnaires or online surveys BIB003 ,  , BIB001 . Some of these papers involve users for both gaining insights to be used in the design process, and assessing the designed prototype BIB003 , BIB024 ,  , BIB013 , BIB001 , BIB012 . The acceptance study perspective includes 16 papers. This perspective entails the conduction of (relatively) large user studies, investigating the acceptability and the adoption of specific wearable devices BIB016 - BIB006 . Seven works use in-depth interviews BIB007 , BIB004 , BIB025 , BIB026 , BIB017 , BIB031 , BIB006 , four use online surveys BIB016 , BIB018 , BIB019 , BIB008 , and one uses questionnaires BIB032 . Two papers adopt a combination of methods: online surveys and interviews BIB027 , or logs and online survey BIB028 . One paper employs sentiment analysis of customers' comments on Amazon.com  . Auto-ethnography is also employed by one work, as a pilot approach to prepare for a contextual analysis BIB009 . In all the cases, the studies are focused on commercial products. A relevant aspect that is worth to be deepened relates to the research methods employed across the three perspectives. These can be divided into user needs elicitation studies, addressed to discover requirements to develop prototypes or define opportunities for creating novel devices, and evaluation studies, aimed at assessing novel or commercial solutions. Table I outlines how the studies are distributed among the three perspectives (some works present more than one study thus belonging to multiple categories). As for the user needs elicitation, questionnaires (both paper and online based), interviews, and observation have been mostly employed. Some of the studies using questionnaires recruited a large number of participants, such as Gradl et al. BIB018 , who involved 227 athletes, Stewart et al. BIB003 , who collected 323 answers from roller derby skaters, and Havlucu et al. BIB027 , who enrolled 1567 members of the Turkish Tennis Federation. However, the majority of them involved more limited samples, such as Aggravi et al. BIB011 , who involved one skiing instructor and seven blind skiers, or Zhao et al. BIB010 who recruited five participants. Interviews conducted to identify user requirements commonly involved a small number of users (less than 20): For example, Carrington et al. BIB007 interviewed five wheelchair athletes and three therapists, while Pan et al. BIB030 interviewed seven weightlifters. Conversely, interviews investigating the situated use of commercial devices involved a higher number of participants (20 or more): Rapp and Tirabeni BIB031 interviewed 20 elite and amateur athletes to discover how wearables integrate into their sports activities; Fritz et al. BIB004 recruited 30 users of commercial activity trackers to gather insights on how to design wearables that can be used over long terms; Gui et al. BIB025 interviewed 31 WeRun users to investigate the influence of preexisting social network in sharing habits; and Jaharrai et al. BIB026 interviewed 29 people about their motivation to do sports. Observation and contextual interviews, instead, are used to a much lesser extent. Mencarini et al. BIB014 observed 6 indoor climbing lessons and interviewed 17 trainees and mountain guides, whereas Patel and O'Kane BIB009 observed 11 participants while exercising at the gym. As for the evaluation, the methods employed can be divided into experimental lab studies and field studies, both using a variety of techniques to gather measures and insights. Experimental lab studies were conducted in "controlled situations" often opting for quantitative inspection techniques or mixed methods. Bogers et al. BIB024 , for instance, employed semistructured interviews, questionnaires, and log data analysis to evaluate jerseys measuring ball possession and giving feedback using light stripes. It is worth noticing that experiments rarely employed longitudinal designs, control groups or pre/post-test interventions. There are, though, some exceptions: For example, Bice et al. BIB016 designed an 8-week, pre-/post-test intervention experiment to assess the effects of wearables on physical activity motivation; Strohrmann et al. BIB002 employed a control group to evaluate how an IMU connected to a smartphone application may improve running technique; Zhao et al. BIB020 used a between-subject design with 36 participants providing pre/postquestionnaires. Field studies, instead, were aimed at assessing wearables "in the wild" leaving users free to use them during their everyday sports and fitness practices. Fedosov et al. BIB021 , for instance, monitored participants in a weeklong winter seminar to study the perceived usefulness and usability of a wearable augmented reality (AR) system for sharing content on ski resort maps. Mauriello et al. BIB005 used observation, interviews, and questionnaires to evaluate a wearable e-textile display aimed at supporting group running. A residual number of works exclusively asked for users' opinions using either questionnaires or semistructured interviews. Kreitzberg et al. BIB017 , for instance, interviewed 25 participants to explore how and with whom people communicate fitness tracker messages. Kräuter et al. BIB022 employed a questionnaire to assess users' feelings toward a wearable prototype for cycling.