A Comparison of Video and Accelerometer Based Approaches Applied to Performance Monitoring in Swimming.

The aim of this paper is to present a comparison of video- and sensor based studies of swimming performance. The video-based approach is reviewed and contrasted to the newer sensor-based technology, specifically accelerometers based upon Micro-Electro-Mechanical Systems (MEMS) technology. Results from previously published swim performance studies using both the video and sensor technologies are summarised and evaluated against the conventional theory that upper arm movements are of primary interest when quantifying free-style technique. The authors conclude that multiple sensor-based measurements of swimmers’ acceleration profiles have the potential to offer significant advances in coaching technique over the traditional video based approach

Sport Biomechanics Applications Using Inertial, Force, and EMG Sensors: A Literature Overview

In the last few decades, a number of technological developments have advanced the spread of wearable sensors for the assessment of human motion. These sensors have been also developed to assess athletes’ performance, providing useful guidelines for coaching, as well as for injury prevention. The data from these sensors provides key performance outcomes as well as more detailed kinematic, kinetic, and electromyographic data that provides insight into how the performance was obtained. From this perspective, inertial sensors, force sensors, and electromyography appear to be the most appropriate wearable sensors to use. Several studies were conducted to verify the feasibility of using wearable sensors for sport applications by using both commercially available and customized sensors. The present study seeks to provide an overview of sport biomechanics applications found from recent literature using wearable sensors, highlighting some information related to the used sensors and analysis methods. From the literature review results, it appears that inertial sensors are the most widespread sensors for assessing athletes’ performance; however, there still exist applications for force sensors and electromyography in this context. The main sport assessed in the studies was running, even though the range of sports examined was quite high. The provided overview can be useful for researchers, athletes, and coaches to understand the technologies currently available for sport performance assessment

Development of a non-invasive motion capture system for swimming biomechanics

Sports researchers and coaches currently have no practical tool that can accurately and rapidly measure the 3D kinematics of swimmers. Established motion capture methods in biomechanics are not well suited for underwater use, either because they i) are not accurate enough (like depth-based systems, or the visual hull), ii) would impair the movement of swimmers (like sensor- and marker-based systems), or iii) are too time consuming (like manual digitisation). The ideal for swimming motion capture would be a markerless motion capture system that only requires a few cameras. Such a system would automatically extract silhouettes and 2D joint locations from the videos recorded by the cameras, and fit a generic 3D body model to these constraints. The main challenge in developing such a system for swimming motion capture lies in the development of algorithms for silhouette extraction and 2D pose detection (i.e., localisation of joints in image coordinates), which need to perform well on images of swimmers—a task that currently available algorithms fail. The aim of this PhD was the development of such algorithms. Existing datasets do not contain images of swimmers, making it impossible to train algorithms that would perform well in this domain. Therefore, during the PhD two datasets of images of swimmers were constructed and hand-labelled: one, called Scylla, for silhouette extraction (3,100 images); and one, called Charybdis, for 2D pose detection (8,000 images). Scylla and Charybdis are the first datasets developed specifically for training algorithms to perform well on images of swimmers. Indeed, using these datasets, two algorithms were developed during this PhD: FISHnet, for silhouette extraction; and POSEidon, for 2D pose detection. The novelty of FISHnet (which outperformed state-of-the-art algorithms on Scylla) lies in its ability to predict outputs at the same resolution as the inputs, allowing it to reconstruct fine-grained silhouettes. The novelty of POSEidon lies in its unique structure, which allows it to directly regress the x and y coordinates of joints without needing heatmaps. POSEidon is almost as accurate as humans at locating the spinal joints of swimmers, which are essential constraints onto which to fit 3D models. Using these two algorithms, researchers will, in the future, be able to assemble a markerless motion capture system for swimming, which will contribute to improving our understanding of swimming biomechanics, as well as providing coaches a tool with which to monitor the technique of swimmers

Modular soft pneumatic actuator system design for compliance matching

The future of robotics is personal. Never before has technology been as pervasive as it is today, with advanced mobile electronics hardware and multi-level network connectivity pushing âsmartâ devices deeper into our daily lives through home automation systems, virtual assistants, and wearable activity monitoring. As the suite of personal technology around us continues to grow in this way, augmenting and offloading the burden of routine activities of daily living, the notion that this trend will extend to robotics seems inevitable. Transitioning robots from their current principal domain of industrial factory settings to domestic, workplace, or public environments is not simply a matter of relocation or reprogramming, however. The key differences between âtraditionalâ types of robots and those which would best serve personal, proximal, human interactive applications demand a new approach to their design. Chief among these are requirements for safety, adaptability, reliability, reconfigurability, and to a more practical extent, usability. These properties frame the context and objectives of my thesis work, which seeks to provide solutions and answers to not only how these features might be achieved in personal robotic systems, but as well what benefits they can afford. I approach the investigation of these questions from a perspective of compliance matching of hardware systems to their applications, by providing methods to achieve mechanical attributes complimentary to their environment and end-use. These features are fundamental to the burgeoning field of Soft Robotics, wherein flexible, compliant materials are used as the basis for the structure, actuation, sensing, and control of complete robotic systems. Combined with pressurized air as a power source, soft pneumatic actuator (SPA) based systems offers new and novel methods of exploiting the intrinsic compliance of soft material components in robotic systems. While this strategy seems to answer many of the needs for human-safe robotic applications, it also brings new questions and challenges: What are the needs and applications personal robots may best serve? Are soft pneumatic actuators capable of these tasks, or âusefulâ work output and performance? How can SPA based systems be applied to provide complex functionality needed for operation in diverse, real-world environments? What are the theoretical and practical challenges in implementing scalable, multiple degrees of freedom systems, and how can they be overcome? I present solutions to these problems in my thesis work, elucidated through scientific design, testing and evaluation of robotic prototypes which leverage and demonstrate three key features: 1) Intrinsic compliance: provided by passive elastic and flexible component material properties, 2) Extrinsic compliance: rendered through high number of independent, controllable degrees of freedom, and 3) Complementary design: exhibited by modular, plug and play architectures which combine both attributes to achieve compliant systems. Through these core projects and others listed below I have been engaged in soft robotic technology, its application, and solutions to the challenges which are critical to providing a path forward within the soft robotics field, as well as for the future of personal robotics as a whole toward creating a better society

SMA-Based Muscle-Like Actuation in Biologically Inspired Robots: A State of the Art Review

New actuation technology in functional or "smart" materials has opened new horizons in robotics actuation systems. Materials such as piezo-electric fiber composites, electro-active polymers and shape memory alloys (SMA) are being investigated as promising alternatives to standard servomotor technology [52]. This paper focuses on the use of SMAs for building muscle-like actuators. SMAs are extremely cheap, easily available commercially and have the advantage of working at low voltages. The use of SMA provides a very interesting alternative to the mechanisms used by conventional actuators. SMAs allow to drastically reduce the size, weight and complexity of robotic systems. In fact, their large force-weight ratio, large life cycles, negligible volume, sensing capability and noise-free operation make possible the use of this technology for building a new class of actuation devices. Nonetheless, high power consumption and low bandwidth limit this technology for certain kind of applications. This presents a challenge that must be addressed from both materials and control perspectives in order to overcome these drawbacks. Here, the latter is tackled. It has been demonstrated that suitable control strategies and proper mechanical arrangements can dramatically improve on SMA performance, mostly in terms of actuation speed and limit cycles

Diferentes perspectivas da ação de membros inferiores nos quatro nados competitivos: uma revisão integrativa

It is currently known that the speed of swimming is a function of the propulsion generated from the lower limbs and not just the upper limbs. However, for years the action of the legs, during swimming, had its importance mitigated. Thus, the objective of this work was to raise, by means of an integrative literature review, the state of the art regarding the importance of the lower limbs in swimming. This research was delimited in the action of surface legs and underwater legs, excluding the analysis of exits and turns. Studies indexed in the following databases were analyzed: Web of Science, PubMed, Scopus, Lilacs and SciELO. The search system included reading of titles, abstracts and articles in full, found through blocks of descriptors that combined main and secondary terms. A total of 154 articles were found, of which 55 were included for qualitative analysis. The results showed that studies on the use of the lower limbs in swimming have a low sample value and a heterogeneous description of the levels of the participants. Breaststroke and underwater swells are the most studied variables. It is recommended to examine the effectiveness of other anthropometric, kinematic and coordination variables to better understand the production of maximum speed and to consider the importance of individual techniques in the action of the legs in swimming. Still, in the field of using the lower limbs in swimming, there are some gaps, which the articles themselves point out. These demands are due to the strength generated by these segments, in addition to the discussion of the importance of considering individual factors in the action of the legs for swimmers.Atualmente se sabe que a velocidade da natação é uma função da propulsão gerada a partir dos membros inferiores e não apenas dos membros superiores. No entanto, por anos, a ação das pernas, durante o nado, teve sua importância mitigada. Dessa forma, o objetivo deste trabalho foi levantar, por meio de uma revisão integrativa da literatura, o estado da arte acerca da importância dos membros inferiores na natação. Esta pesquisa foi delimitada na ação das pernas de superfície e pernas subaquáticas, excluindo-se as análises das saídas e viradas. Foram analisados estudos indexados nas seguintes bases de dados: Web of Science, PubMed, Scopus, Lilacs e SciELO. A sistematização de busca incluiu leitura de títulos, resumos e artigos na íntegra, encontrados por meio de blocos de descritores que combinaram termos principais e secundários. Um total de 154 artigos foi encontrado, dos quais 55 foram incluídos para análise qualitativa. Os resultados mostraram que os estudos sobre a utilização dos membros inferiores na natação possuem baixo valor amostral e descrição heterogênea dos níveis dos participantes. O nado peito e as ondulações subaquáticas são as variáveis mais estudadas. Preconiza-se examinar a eficácia de outras variáveis ​​antropométricas, cinemáticas e de coordenação para entender melhor a produção da velocidade máxima e considerar a importância de técnicas individuais na ação das pernas na natação. Ainda, no campo da utilização dos membros inferiores na natação, existem algumas lacunas, as quais os próprios artigos apontam. Essas  demandas ficam por conta da força gerada por esses segmentos, além da discussão da importância em se considerarem fatores individuais na ação das pernas para os nadadores