Technical evaluation of swimming performance is an essential factor of elite athletic preparation. Novel methods of analysis, incorporating body worn inertial sensors (i.e., Microelectromechanical systems, or MEMS, accelerometers and gyroscopes), have received much attention recently from both research and commercial communities as an alternative to video-based approaches. This technology may allow for improved analysis of stroke mechanics, race performance and energy expenditure, as well as real-time feedback to the coach, potentially enabling more efficient, competitive and quantitative coaching. The aim of this paper is to provide a systematic review of the literature related to the use of inertial sensors for the technical analysis of swimming performance. This paper focuses on providing an evaluation of the accuracy of different feature detection algorithms described in the literature for the analysis of different phases of swimming, specifically starts, turns and free-swimming. The consequences associated with different sensor attachment locations are also considered for both single and multiple sensor configurations. Additional information such as this should help practitioners to select the most appropriate systems and methods for extracting the key performance related parameters that are important to them for analysing their swimmers’ performance and may serve to inform both applied and research practices.

In elite swimming, a broad range of methods are used to assess performance, inform coaching practices and monitor athletic progression. The aim of this paper was to examine the performance analysis practices of swimming coaches and to explore the reasons behind the decisions that coaches take when analysing performance. Survey data were analysed from 298 Level 3 competitive swimming coaches (245 male, 53 female) based in the United States. Results were compiled to provide a generalised picture of practices and perceptions and to examine key emerging themes. It was found that a disparity exists between the importance swim coaches place on biomechanical analysis of swimming performance and the types of analyses that are actually conducted. Video-based methods are most frequently employed, with over 70% of coaches using these methods at least monthly, with analyses being mainly qualitative in nature rather than quantitative. Barriers to the more widespread use of quantitative biomechanical analysis in elite swimming environments were explored. Constraints include time, cost and availability of resources, but other factors such as sources of information on swimming performance and analysis and control over service provision are also discussed, with particular emphasis on video-based methods and emerging sensor-based technologies.

The presence of a venous pumping mechanism in the foot may be significant for venous return in the lower extremities. However, there has been a lack of conclusive research in the area to date and controversy still exists over the detailed anatomy and physiologic mechanism of the venous foot pump. A full understanding of the anatomy and physiology of the venous foot pump is essential for designing effective interventions for the prevention, treatment, and management of venous disease in the lower limbs. This article highlights and discusses the relevant literature relating to the anatomy and physiology of the venous foot pump. In addition, the plantar aspects of 10 cadaveric feet were dissected. These dissections revealed the presence of a previously unreported secondary deep plantar arch and/or deep system of venous connections in the foot and facilitated a more detailed description of the patterns of doubling and branching of the primary veins of the foot. The results of these dissections are discussed within the context of previous work in the field with the aid of detailed diagrams of the dissected feet and may provide a backdrop for the physiology of the venous foot pump and its potential role in lower limb circulation. This is discussed in the last section of the article, which also highlights existing controversy regarding the role of weight bearing and muscular contraction as the dominant mechanisms for venous pumping in the foot. Anat Rec, 293:370-378, 2010. V V C 2009 Wiley-Liss, Inc.

This paper explores the application of video-based methods for the analysis of competitive swimming performance. A systematic search of the existing literature was conducted using the following keywords: swim*, performance, analysis, quantitative, qualitative, camera, video on studies published in the last five years, in the electronic databases ISI Web of Knowledge, PubMed, Science Direct, Scopus and SPORT discus. Of the 384 number of records initially identified, 30 articles were fully reviewed and their outcome measures were analysed and categorised according to (i) the processes involved, (ii) the application of video for technical analysis of swimming performance and (iii) emerging advances in video technology. Results showed that video is one of the most common methods used to gather data for analysing performance in swimming. The process of using video in aquatic settings is complex, with little consensus amongst coaches regarding a best-practice approach, potentially hindering usage and effectiveness. Different methodologies were assessed and recommendations for coaches, sport scientists and clinicians are provided. Video is an extremely versatile tool. In addition to providing a visual record, it can be used for qualitative and quantitative analysis and is used in both training and competition settings. Cameras can be positioned to gather images both above and below the water. Ongoing advances in automation of video processing techniques and the integration of video with other analysis tools suggest that video analysis will continue to remain central to the preparation of elite swimmers.

This study investigated the hemodynamic properties of the plantar venous plexus (PVP), a peripheral venous pump in the human foot, with Doppler ultrasound. We investigated how different ways of introducing mechanical changes vary in effectiveness of displacing blood volume from the PVP. The contribution of the PVP was analyzed during both natural and device-elicited compressions. Natural compressions consisted of weight bearing on the foot and toe curl exercises. Device-elicited compressions consisted of intermittent pneumatic compression (IPC) of the foot and electrically elicited foot muscle contractions. Ten healthy participants had their posterior tibial, peroneal, anterior tibial, and popliteal vein blood flow monitored while performing these natural and device-elicited compressions of the PVP supine and in an upright position. Results indicated that 1) natural compression of the PVP, weight bearing and toe curls, expelled a significantly larger volume of blood than device-elicited PVP compression, IPC and electrical stimulation; 2) there was no difference between the venous volume elicited by weight bearing and by toe curls; 3) expelled venous volume recorded at the popliteal vein under all test conditions was significantly greater than that recorded from the posterior tibial and peroneal veins; 4) there was no significant difference between the volume in the posterior tibial and peroneal veins; 5) ejected venous volume recorded in the upright position was significantly higher than that recorded in the supine position. Our study shows that weight bearing and toe curls make similar contributions to venous emptying of the foot.