Despite a strong commercial trend towards wearable technology, this thesis considers the distal devices that have played an important role in our lives for over twenty years. Suggesting that the distance we have had between our bodies and our devices has given us the space to form meaningful relationships; the research explores how these relationships change when our devices migrate onto and into our bodies in the form of wearable technologies. The methodology of performative scenarios is developed to examine examples of relationships between people and their devices. Using examples of technologies that live with us now to inform the design of future technological developments reflects a post-phenomenological perspective calling for a materially oriented design approach. This thesis will explore this approach through focusing on the question; what would we lose if our distal devices became wearable devices? Ideations aiming to prevent any loss caused by the transition of devices from distal to wearable will provide examples of post-phenomenological wearable technology that not only maintains our relationships with our devices, but also helps our relationships to grow.

This thesis investigates the assumed affordance of haptic technology in a wearable context. This work position itself within the internet of things where wearable and connected objects have established themselves as a sub-domain in the area. Some argued that haptic technologies provide certain benefits when creating interfaces for wearable technologies. However, their seams to be a lack of studies investigating the natural responses to haptic technology from a user perspective. To investigate the assumed benefits of haptic technology, we have developed a prototype of a wearable haptic system. This system consists of two jacket were each jacket contains 16 touch sensitive sensor and haptic actuators. All interactions with the sensor of one jacket are mirrored with a haptic feedback in the other jacket. The purpose of this system is to investigate the initial responses and accord of haptic technology by users. The reason for doing this is to develop guidelines for further investigation into haptic technology as a means for creating wearable objects with a non-screen based interfaces.The study concludes there to be some merit to the use of rhythm for creating haptic interaction patterns as well as haptic technology affording a simple and natural dialog in human computer interaction. Further, we also conclude that there is some merit to haptic affording faster learning curves in novel non-screen based interaction and are suitable for providing clear feedback. This study also shows limitations for haptic technology. Haptics seem less proficient for interfaces existing in a system as well as handling errors. This study also proved problematic because of the lack in clearly defined methods for investigating novel non-screen based interfaces.In chapter two of this thesis we first present a theoretical overview of wearable’s generally and how haptic technology position itself within wearable technology. In chapter three, we move on by introducing our methods of research. Based on our theory we then frame the technological outline of the project and practical implementation. We follow this by presenting the results in chapter five from our user testing conducted with the prototype. We end our thesis with a discussion in chapter six with presenting the principal findings together with our discussion and future developments in chapter seven.

Resistance training has shifted towards a high- vs low-load training approach. Heavier loads are suggested to maximally recruit motor units and optimize strength adaptations, whereas lower loads stimulate hypertrophy. However, a majority of the research has not used a true strength range when assessing load. Therefore, the purpose of this investigation was to examine and determine significant differences in strength, body composition, and hormonal markers over nine weeks of high- or low-load resistance training. Secondary purposes of the current investigation were to assess and quantify training load for resistance training using sEMG sensor-embedded compression shorts. 17 recreationally-trained males were randomized into two groups with training loads of 30 or 85% 1-RM. Both groups completed nine weeks of whole-body resistance training three days per week, with exercises performed as three sets to failure per movement. Measures were collected at baseline and every three weeks after, including muscle thickness, body composition, isometrics/isokinetic strength, and hormonal status (testosterone and cortisol). Predicted 1-RM testing was performed pre- and post-training. Both groups demonstrated significant hypertrophy and strength, although the 85% showed greater improvements in the predicted 1-RM and the isokinetic peak torque values. There were also significant differences between groups for muscle load and training load as measured by the wearables, indicating the technology was able to differentiate between resistance training intensities. However, there were no changes in any of the hormonal markers either in basal levels or acutely post-exercise. Overall, our results suggest a similar hypertrophy and hormone response occurs in both low- and high-load groups when training to failure, but the high-load results in greater strength improvements and higher muscle load output when measured by wearable technology.

There has been a recent increase in breathing as an activity within HCI; however, breathing as the source of voice has not been explored. This thesis explores how ADA (air-driven actuator), a haptic wearable garment, may be used by singers to connect with their breath. Primarily through first-person engagement with vocal training and first-person evaluation of ADA’s capability to support vocal practice, the thesis addresses how the garment functionally and experientially supports singers’ movements. Thematic analysis results in two main lines of functional use (demonstrations, and prompts), and engagement with the garment in these two usages builds three conceptualizations of how ADA can align with a singer’s breath (through posture adjustments, inhalation as expansion, and inhalation as tension). Further thematic analysis shows how users characterize experiences with ADA as distinguished by anticipation or layering, offering insight into what experimental qualities underlie the functional use of ADA. The thesis highlights implications for future generative work in the breathing design space, offering tension-release as a breath representation, and a suggestion to explore exhalation duration as a breath parameter through the prolongations of exhalations in singing. Furthermore, it highlights layering as a quality that may be of relevance to further development of ADA, or other experience-oriented technology that aims to support movement practice.

Cardiovascular workouts offer numerous health benefits, yet beginners often find it challenging to initiate them. Existing wearable technologies, although providing valuable feedback such as heart rate zones, often disrupt the workout flow and distract users due to the need for interaction with the wearable display. In response, we propose an alternative feedback mechanism: cadence, measured in steps per minute. This feedback mechanism uses multiplicative control to produce the correct cadence for the user’s target heart rate (HR). To model the HR and cadence relationship, a first-order system was used. The prototype implementation of this system was completed in Arduino, using a force sensitive resistor (FSR) to measure the user’s cadence and a POLAR HR strap to measure the user’s HR. The cadence is updated every 10 seconds to allow the user to sync to the cadence metronome provided by earbuds. This proposed system has shown promising experimental results for both moderate-intensity and high-intensity workouts, skipping the transition zone between them. This allows the user to avoid awkward workout intensities between a fast walk and a jog.

Trip-induced falls are a leading cause of injuries among adults aged 65 years or older. Perturbation-based balance training (PBT) has emerged as an exercise-based fall prevention intervention and shown efficacy in reducing the risk of trip-induced falls. The broad goal of my PhD research was to advance the application of this so-called trip training through three studies designed to address existing knowledge gaps. First, trip training is commonly conducted with the aid of costly specialized treadmills to induce trip-like perturbations. An alternative version of trip training that eliminates the need for a treadmill would enhance training feasibility and enable wider adoption. The goal of the first study was to compare the effects of non-treadmill training (NT), treadmill training (TT), and a control (i.e., no training) on reactive balance after laboratory-induced trips among community-dwelling older adults. After three weeks of the assigned intervention, participants were exposed to two laboratory-induced trips while walking. Results showed different beneficial effects of NT and TT. For example, NT may be more beneficial in improving recovery step kinematics, while TT may be more beneficial in improving trunk kinematics, compared to the control. While the first study showed the effects of PBT on laboratory-induced trips, little is known about how such training affects responses to real-world trips. Responses to real-world trips may be captured using wearable inertial measurement units (IMUs), yet IMUs have not been adequately validated for this use. Therefore, the goal of the second study was to investigate the concurrent validity of IMU-based trunk kinematics against the gold standard optical motion capture (OMC)-based trunk kinematics after overground trips among community-dwelling older adults. During two laboratory-induced trips, participants wore two IMUs placed on the sternum and shoulder, and OMC markers placed at anatomical landmarks of the trunk segment. Results showed that IMU-based trunk kinematics differed between falls and recoveries after overground trips, and exhibited at least good correlation (Pearson's correlation coefficient, r > 0.5) with the gold standard OMC-based trunk kinematics. The goal of the third study was then to explore differences in tripping kinematics between the laboratory and real world using wearable IMUs among community-dwelling older adults. Participants were asked to wear three IMUs (for sternum and both feet) and a voice recorder to capture their responses to real-world losses of balance (LOBs) during their daily activities for three weeks. Results showed a higher variance in laboratory-induced trips than real-world trips, and the study demonstrated the feasibility of using IMUs and a voice recorder to understand the underlying mechanisms and context of real-world LOBs. Overall, this work was innovative by evaluating a non-treadmill version of trip training, establishing the validity of IMUs in capturing kinematic responses after overground trips, and applying IMUs and a voice recorder to assess tripping kinematics in the real world. The results from this work will advance the use of PBT to reduce the prevalence of trip-induced falls and to investigate the real-world effects of such trip training in future studies. / Doctor of Philosophy / Trips and falls are a major health problem especially among older adults who are aged 65 years or older. Researchers have developed an innovative exercise-based fall prevention training program, which has shown to be helpful in reducing trips and falls. The broad goal of my PhD research was to advance the use of this so-called trip training through three new research studies. First, specialized treadmills are commonly used for trip training to simulate trip-induced falls. An alternative version of trip training without a treadmill would allow more people to receive benefits from this training. The goal of the first study was to compare the effects of non-treadmill training (NT), treadmill training (TT), and no training on balance recovery after tripping in the laboratory. Older adults living in the local community were recruited as research participants and completed NT, TT, or no training over three weeks. After that, they attended a laboratory session where they were tripped twice while walking on a walkway. Results showed that NT helped to take a longer and faster recovery step, while TT helped to limit trunk forward bending during tripping, both of which are important movements to prevent falling after tripping. While the first study showed benefits of trip training in the laboratory, not much is known about the benefits of trip training in the real world. Wearable sensors called inertial measurement units can record body movements without laboratory motion capture cameras, but their ability to record dynamic body movements during tripping needs to be tested. The goal of the second study was to evaluate the capabilities of these wearable sensors on recording trunk movements during tripping and compare them to those recorded by laboratory motion capture cameras. Participants were tripped twice in the laboratory, and their trunk movements were recorded by several wearable sensors and laboratory motion capture cameras. Results showed that these wearable sensors can distinguish between fallers and non-fallers after tripping, and that the trunk movements recorded by the wearable sensors were associated with those recorded by the laboratory motion capture cameras. With this confirmation, the third study was designed to compare balance recovery after tripping between the laboratory and real world using wearable sensors. Participants were asked to wear three wearable sensors and a voice recorder during their daily activities for three weeks. The wearable sensors recorded their trunk and feet movements, while the voice recorder was used for participants to provide detailed explanations of balance losses they experienced. Results showed a higher variability in balance recovery from the laboratory trips compared to the real-world trips. In addition, this study demonstrated that wearable sensors and a voice recorder can be used to study how people reacted to a balance loss and what they did to recover (or fall) from it. Overall, my PhD research work suggested a new version of trip training that does not require a treadmill, proved that wearable sensors can be used to record important body movements during tripping, and demonstrated the method to study balance recovery responses in the real world using wearable sensors. The results from the three studies will promote the use of trip training and provide guidelines for evaluating benefits of trip training in the real world.

The World Health Organization (WHO) estimates 488 million people worldwide suffer from a visual impairment and of these about 327 million have severe visual impairments. Some individuals with severe visual impairments can navigate and orient independently in well-known surroundings, but even for these people independent navigation and orientation are likely to be a challenge in unfamiliar places. To overcome these challenges, assistive technologies have been developed to support independent wayfinding tasks; however, those with severe visual impairments often experience frustration when they try to use assistive technologies since these technologies lack address the environmental factors that influence their independent wayfinding. This research developed and evaluated the efficacy of a framework called an environmental user interface (EUI). In particular, this research explored whether or not the proposed EUI framework was effective when used with user-centered design (UCD) to design a wayfinding system to capture environmental requirements, thus aiding those with severe visual impairments. Two studies, the first of which consisted of a requirements elicitation and the second usability testing, were conducted. The studies revealed that the EUI framework was indeed more effective than the conventional UCD design method alone in identifying environmental factors, and participants with severe visual impairments preferred to use the prototype designed using UCD and the EUI framework. The proposed EUI framework was found to be an effective way to enhance the design process as it played an important role in eliciting a greater number of environmental factors, and hence produced a device that was preferred by the users with visual impairments. Both prototypes influenced how well the wayfinding tasks were performed by the five participants with severe visual impairments, but the prototype implemented based on the requirements elicited by UCD and the EUI framework was much preferred by the participants. / Ph. D.

As human dependence on electronic devices grows, there is an emerging need on finding sustainable power sources for low power electronics and sensors. One of the promising possibilities in this space is the human body itself. Harvesting significant power from daily human activities will have a transformative effect on wearables and implantables. One of the main challenges in harvesting mechanical energy from human actions is to ensure that there is no effect on the body itself. For this reason, any intrusive mechanism will not have practical relevance. In this dissertation, novel non-intrusive energy harvesting technologies are investigated that can capture available energy from body, motion, and surroundings. Energy harvesting from the body is explored by developing a wrist-based thermoelectric harvester that can operate at low-temperature gradients. Energy harvesting from motion is investigated by creating a backpack and shoe sole. These devices passively store kinetic energy in a spring that is later released to a generator when it is not intrusive to the user kinematics. Lastly, energy harvesting from immediate surroundings is investigated by designing a two degree of freedom vibration absorber that is excited by electromagnetic fields found in common household appliances. These novel solutions are shown to provide consistent electrical power from wasted energy. Harvester designs are extensively modeled and optimized device architectures are manufactured and tested to quantify the relevant parameters such as output voltage and power density. / Doctor of Philosophy / Energy harvesting is the action to transform energy in the form of heat, relative motion, light, etc. into useful electrical energy. An example of an energy harvester is a solar cell which converts energy in the form of light to electricity. Our body consumes a considerable amount of energy to maintain our body temperature and achieve everyday movements, i.e., walking, jumping, etc. The purpose of this research was to fabricate, model and test wearable energy harvesters in the form of a backpack, a shoe sole, a watch, and a cantilever beam to charge mobile electronics on the go. Electrical energy is harvested from human motion by using the relative displacement between the human torso and a payload. Similarly, the ankle joint is used to produce electricity by using the relative rotation between the foot and shank. The difference in temperature between the ambient air and the human body is used to generate enough electricity to power a wrist watch. Finally, energy is harvested from everyday surroundings by using a cantilever beam which absorbs magnetic fields coming from power cords and able to power sensors.

Non-planar additive manufacturing (AM) technologies, such as microextrusion 3D printing processes, offer the ability to fabricate conformal electronics with impressive structure and function on curvilinear substrates. Although various available methods offer conformal 3D printing capability on objects with limited geometric complexity, a number of challenges remain to improve feature resolution, throughput, materials compatibility, resultant function and properties of printed components, and application to substrates of varying topography. Hence, the overall objective of this dissertation was to create new non-planar AM processes that are compatible with personalized and anatomical computer-aided design workflows for the fabrication of conformal electronics and form-fitting wearables. After reviewing the current state of knowledge and state of the art, significant challenges in non-planar AM have been identified as: 1) limited non-planar AM path planning capability that synergizes with personalized or anatomical object surface modification, 2) limited approaches for printed and non-printed component integration on non-planar substrates. To address these challenges, a template-based reverse engineering workflow is proposed for conformal 3D printing electronics and form-fitting wearable devices on anatomical structures. This work was organized into three complementary tasks that enhance non-planar AM capabilities: 1） To achieve anatomical tissue-sensor integration, 3D scanning-based point cloud data acquisition and customized 3D printable conductive ink are proposed for capturing the topographical information of patient-specific malformations and integrating conformal sensing electronics across anatomical tissue-device interface. 2） To fabricate conformal antennas on flexible thin-film polymer substrates, a versatile method for microextrusion 3D printing of conformal antennas on thin film-based structures of random topography is proposed to control the ink deposition process across the curvilinear surfaces of freeform Kapton-based origami. 3） To simplify the fabrication process of form-fitting wearable devices with fiber-based form factors and self-powered capability, an innovative 3D printing process is proposed to achieve coaxial multi-material extrusion of metal-elastomer triboelectric fibers. By developing new advanced non-planar printing processes and conformal toolpath programming strategies, the utility of non-planar AM could be further expanded for fabricating various personalized implantable and wearable multi-functional systems, including novel 3D electronics. In summary, this work advances capability in additive manufacturing processes by providing new advances in multi-material extrusion processes and personalized device design and manufacturing workflows. / Doctor of Philosophy / The ability to assemble electronic devices on three-dimensional objects with complex geometry is essential for developing next-generation wearable devices. Additive manufacturing processes, commonly referred to as 3D printing, now offer the ability to fabricate conformal electronics on surfaces and objects with non-planar geometry. This dissertation aims to expand non-planar 3D printing capabilities for applications to objects with anatomical or personalized structures, such as patient-specific malformation and origami. The proposed methods in this dissertation are focused on addressing challenges, such as the acquisition of object 3D topographical data, material selection, and tool path programming for objects that exhibit anatomical geometry. The utility of the proposed methods is demonstrated with practical applications to 3D-printed conformal electronics and wearable devices for monitoring human behavior and organ healthcare. This dissertation contributes to improving manufacturing capability and outcomes of 3D-printed form-fitting wearable and implantable devices. Future work may emphasize developing biocompatible functional ink and toolpath programming algorithms with real-time adaptation capability.

The purpose of this thesis was to determine the proportion of participants enrolled in a community-based weight loss program that would accept and use a wearable device (Fitbit) if included as part of the program. A sample of 526 newly enrolled, adult, female weight loss program participants (BMI ≥ 30 kg/m2 ) were recruited. Participants were randomized to either a Fitbit experimental condition or no-Fitbit control condition, and received emailed information on program features. The experimental condition email also included a free Fitbit offer. The full sample (n=526) was 44±12.6 years old with a BMI of 37±6.2 kg/m2. The proportion of experimental sample (n=266) that accepted and synced was 50% and 23%, respectively. Twenty-two participants in the control condition (8%) also independently obtained and synced a Fitbit. Ninety-nine percent passively declined (did not respond to request for Fitbit color and size information). Those that declined were older (46±13.4 vs. 42±11.3 years of age, p=.001) and weighed less (214±38.9lbs. vs. 231±41.3lbs., p=.01) than those who accepted. Those in the experimental sample who synced were younger (42±10.0 vs. 45±13.2 years of age, p=.012), and weighed more (237±45.2lbs. vs. 217±38.1lbs., p=.002) than those who accepted but did not sync. This thesis provides preliminary support that 23% of participants will accept and sync a free wearable device. These data can be used for decision making, combined with effectiveness and cost data, and research on wearable activity trackers and community, incentive, and web-based weight loss. / Master of Science