7,335 research outputs found

    The Learning Pathways of Ironman Triathletes: Case Studies of Age-Group Ironman Triathletes

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    The Ironman Triathlon is an epic endurance event consisting of a 2.4-mile swim, a 112-mile bike ride, and a 26.2-mile run. There is paucity in the literature relating to how athletes learn how to negotiate this event. This qualitative study was conducted over a 9 month period, to align with the 2013 Ironman training and racing season. Seven athletes were selected for participation in the study. Utilizing a case study approach, the Ironman athletes’ learning pathways were examined through in-depth interviews and audio and video content personally captured by the participants. The learning pathways revealed the athletes initially learned through cognitive means, i.e. social interaction, reading, Internet sources, and the observation of others. As athletes traversed the learning pathway, they subsequently operationalized the knowledge they learned and constructively made it meaningful to their respective personal training and racing situations. At the terminal end of the learning pathway, the athletes operationalized the learned content in an experiential learning cycle. During the entire learning pathway, the athletes practiced the learned content, which is best characterized as behavioral learning. The audio and video content provided by the athletes empirically validated the interviews. The interviews with the athletes were coded. Some unifying themes emerged from the data independent of cognitive, constructivist, behavioral, or experiential learning theories; e.g. the importance of mental toughness, the understanding of pain during the training and racing process, how success is measured, the importance of training with a power meter, and motivating factors

    Locomotor adaptations during RaceRunning in people with neurological motor disorders

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    The aim of this study was to examine strategies to absorb impact shock during RaceRunning in participants with neurological motor disorders. For this purpose, eight RaceRunning athletes (four males and four females) voluntarily took part in this study. Each participant performed a series of 100-m sprints with a RaceRunning bike. Acceleration of the tibia and head was measured with two inertial measurement units and used to calculate foot impact shock measures. Results showed that RaceRunning pattern was characterized by a lack of impact peak in foot–ground contact time and the existence of an active peak after foot contact. Due to the ergonomic properties of the RaceRunning bike, shock is attenuated throughout the stance phase. In conclusion, the resultsrevealed that RaceRunning athletes with neurological motor disorders are capable of absorbing impact shock during assisted RaceRunning using a strategy that mimics runners without disabilitie

    TagBook: A Semantic Video Representation without Supervision for Event Detection

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    We consider the problem of event detection in video for scenarios where only few, or even zero examples are available for training. For this challenging setting, the prevailing solutions in the literature rely on a semantic video representation obtained from thousands of pre-trained concept detectors. Different from existing work, we propose a new semantic video representation that is based on freely available social tagged videos only, without the need for training any intermediate concept detectors. We introduce a simple algorithm that propagates tags from a video's nearest neighbors, similar in spirit to the ones used for image retrieval, but redesign it for video event detection by including video source set refinement and varying the video tag assignment. We call our approach TagBook and study its construction, descriptiveness and detection performance on the TRECVID 2013 and 2014 multimedia event detection datasets and the Columbia Consumer Video dataset. Despite its simple nature, the proposed TagBook video representation is remarkably effective for few-example and zero-example event detection, even outperforming very recent state-of-the-art alternatives building on supervised representations.Comment: accepted for publication as a regular paper in the IEEE Transactions on Multimedi

    Development of site-specific biomechanical indices for estimating injury risk in cycling

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    In this paper we present novel biomechanical indices for site-specific assessment of injury risk in cycling. The indices are built from a multifactorial analysis based on the kinematics and kinetics of the cyclist from the biomechanical side, and muscle excitations and muscle synergies from the neurophysiological side. The indices are specifics for three body regions (back, knee, ankle) which are strongly affected by overuse injuries in cycling. We use these indices for injury risks analysis of a recreational cyclist, who offered to participate in the experiments. The preliminary results are promising towards the use of such indices for planning and/or evaluating training schedule with the final goal of reducing non-traumatic injuries in cycling

    A retrospective international study on factors associated with injury, discomfort and pain perception among cyclists

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    Although cycling has been associated with overuse/fatigue and acute injuries, there is lack of information regarding associated risk factors and prevention factors. The objective of the study was to determine the factors associated with injury, and perceptions of discomfort and pain in cyclists. A total of 739 cyclists completed an online questionnaire between February and October 2016. The questionnaire acquired information on participant demographics, characteristics related to cycling profile and fitness training, bike components and cycling posture, self-reported perceptions of comfort and pain, and injuries sustained in the last 12 months. Logistic regression models estimated odds ratios (OR) and 95% confidence intervals (95%CI) that examined factors associated with reporting overuse/fatigue injury, acute injury, body discomfort, saddle discomfort, and pain while cycling. Odds of reporting an overuse/fatigue injury increased when the cyclists complemented training with running (OR = 1.74; 95%CI = 1.03-2.91) or swimming (OR = 2.17; 95%CI = 1.19-3.88), and with reported pain while cycling (OR = 1.17; 95%CI = 1.05-3.69) and not cycling (OR = 1.76; 95%CI = 1.07-2.90). Odds of reporting an acute injury increased when biking to work (OR = 1.79; 95%CI = 1.07-2.86), and decreased with increased average cycling speed (1-km/h decrease OR = 0.93; 95%CI = 0.88-0.97), and compared to low-end bike, with the use of mid-range (OR = 0.25; 95%CI = 0.09-0.72) and high-end bike (OR = 0.34; 95%CI = 0.13-0.96). Although body discomfort was only associated with saddle discomfort and the presence of pain during cycling, saddle discomfort was also associated with biking to work (OR = 0.46; 95%CI = 0.22-0.88). Finally, pain perception was associated with a number of factors such as ride to work, core training, cycling experience, saddle discomfort, pain while not cycling. Numerous factors are associated with injury, and perceptions of discomfort and pain in cyclists. Such factors should be considered when developing training routines, bicycle maintenance best practices, and injury prevention programs

    Assessment of joint kinetics in elite sprint cyclists

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    Sprint cycling requires the production of explosive muscle power outputs up to very high pedalling rates. The ability to assess muscular function through the course of the sprint would aid training practices for high-level performers. Inverse dynamics provides a non-invasive means of estimating the net muscle actions acting across any joint contributing to movement. However, analysis of joint kinetics requires motion-capture techniques that present some unique challenges for cycling. This thesis presents three studies investigating the application of a custom-designed force pedal system to examine the joint kinetics of elite trained track sprint cyclists. To provide the basis for selecting appropriate testing procedures, study one evaluated differences between two- and three- dimensional techniques while assessing joint kinetics of seated and standing sprint cycling at optimal cadence (the cadence where peak power is delivered). Study two examined the impact of cadence and seating position on joint kinetics, while determining testing reliability using the three-dimensional process. Coefficients of variation were established for between- and within- days repetitions of sprint performance at optimal cadence, and cadences 30% lower and 30% higher, in both seated and standing positions. Study three compared joint kinetics of sprint cycling performance with commonly-applied resistance-training exercises in an elite cycling cohort, in order to better understand training specificity. Joint-specific torque-angular velocity relationships were established from seated and standing sprinting at three cadences and the clean exercise at three loads, with other strength-based exercises examined at maximal load only. Study one determined that flattened projections of the 3D motion into 2D resulted in significant differences in joint powers calculated in the sagittal-plane. When using 2D methods, knee joint power was significantly lower and hip transfer power significantly greater, while hip range of motion was lower and the angle where hip peak power occurred later in the crank cycle. These results indicate that 3D processes should be used where evaluation of absolute values are important, although 2D processes may still be acceptable where relative differences are being assessed. It was observed in Study two that, while crank and total muscle power upheld a quadratic power-cadence relationship, joint-specific powers were uniquely related to cadence and riding position. Crank and joint-specific optimal cadences for power production were distinctly different. The hip displayed a linear maximum power-cadence relationship in seated but quadratic in standing position, with the reverse observed at the knee. Ankle and hip transfer powers both linearly declined with cadence irrespective riding position. In such a case, joint-specific power contribution, hence distribution of muscular effort, cannot be directly inferred from power assessed at the crank. Reliability was highest for crank and total muscle power, particularly at the riders’ optimal cadence. Reliability of joint powers were somewhat lower and uniquely dependent on joint, joint action and trial condition. Results indicate that external power output at the crank is relatively stable across sprints, despite variation in the underlying muscular contributions. Results of study three showed equivalence in the torque-angular velocity relationships at the hip in sprint cycling and different phases of the clean. No such relationship was evident at the knee or ankle. In contrast to the negative linear relationships observed in all other conditions, ankle mechanics in sprinting showed a positive linear relationship highlighting a distinct functional role of this joint. Highest maximal torques at the hip and knee were observed during unilateral single rack pull and step-up exercises, respectively, supporting their efficacy for improving the maximum strength characteristics at these joints. The results of this thesis indicate that joint kinetics are an effective means of assessing muscular performance in highly-trained track sprint cyclists and provide information on the underlying strategies that could not be assessed through conventional testing of power at the crank. The use of 3D processes is recommended where accuracy of assessment and absolute values are important. Flexibility of 2D processes may be advantageous in field-based settings and may be acceptable where only relative change is of interest. High reliability of 3D testing supports its use in monitoring of athletes, with the reliability data presented in this thesis providing an indication of the smallest meaningful changes in various trial conditions. Low coefficients of variation observed in crank and muscle power terms, despite greater variation in joint powers, suggest motor control strategies dynamically respond to task conditions while maintaining a consistent external power. Resistance exercises are seen to display jointspecific profiles that characterise relative hip- or knee- dominance. The comparison of these profiles with those of sprint cycling can help inform exercise selection for strength development of elite riders. The ability to monitor changes and target training intervention at joint level provides a unique approach to athlete development. Outcomes of this thesis support the practical application of joint kinetic assessment in aiding training practices to the highest levels of competition in track sprint cycling. Indeed, the equipment, methods and knowledge obtained from this research is currently applied in the preparation of Australia’s best sprint cyclists
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