Extreme leg motion analysis of professional ballet dancers via MRI segmentation of multiple leg postures

Purpose: Professional ballet dancers are subject to constant extreme motion which is known to be at the origin of many articular disorders. To analyze their extreme motion, we exploit a unique magnetic resonance imaging (MRI) protocol, denoted as ‘dual-posture' MRI, which scans the subject in both the normal (supine) and extreme (split) postures. However, due to inhomogeneous tissue intensities and image artifacts in these scans, coupled with unique acquisition protocol (split posture), segmentation of these scans is difficult. We present a novel algorithm that exploits the correlation between scans (bone shape invariance, appearance similarity) in automatically segmenting the dancer MRI images. Methods: While validated segmentation algorithms are available for standard supine MRI, these algorithms cannot be applied to the split scan which exhibits a unique posture and strong inter-subject variations. In this study, the supine MRI is segmented with a deformable models method. The appearance and shape of the segmented supine models are then re-used to segment the split MRI of the same subject. Models are first registered to the split image using a novel constrained global optimization, before being refined with the deformable models technique. Results: Experiments with 10 dual-posture MRI datasets in the segmentation of left and right femur bones reported accurate and robust results (mean distance error: 1.39 ± 0.31mm). Conclusions: The use of segmented models from the supine posture to assist the split posture segmentation was found to be equally accurate and consistent to supine results. Our results suggest that dual-posture MRI can be efficiently and robustly segmente

Occupational injuries in professional dancers

Balet je u isto vrijeme i umjetnost i sport. Fizički zahtjevi u baletu su veoma jedinstveni. Pomicanje granica vlastitog tijela radi postizanja elegancije i estetike nadilaze biologiju ljudskog tijela. Profesionalni plesači u svijet baleta često ulaze u vrlo ranoj dobi. Školovanje je dugotrajno, mukotrpno i zahtijeva mnogo odricanja, rada i upornosti. Sistem selekcije postaje sve stroži na višim razinama školovanja. Intenzitet vježbi raste. Balet zahtjeva posebnu obuću, tzv. špice. Špice su posebno dizajnirane papučice u kojima plesač stoji na vrhovima prstiju sa stopalima u plantarnoj fleksiji. Biomehanika tijela u plesača se mijenja. Početni baletni položaj zahtijeva izravnate fiziološke krivine kralježnice, kontrakcije mišića prednje trbušne stjenke, ruka moraju biti u položaju prirodnog luka s izdignutim vratom. Noge idu u vanjsku rotaciju iz kuka s otvorenim stopalima prema kutu od 180º s potpunom ekstenzijom u koljenom zglobu. Baletni sat sastoji se od dva dijela, vježbi na štapu i centralno izvođenje nastave. Vježbe na štapu služe zagrijavanju tijela za centralni dio sata. U ciklusu sezone jedne baletne trupe do ozljeda najviše dolazi u periodu izvođenja baletne nastave i za vrijeme nastupanja. Rizični faktori koji povećavaju rizik nastanka ozljede su svakako vrsta poda na kojem se pleše i baletne špice. Najveći rizik za pojavu ozljeda imaju upravo donji ekstremiteti i kralježnica. Kod muških plesača također dolazi do ozljeda gornjih ekstremiteta zbog podizanja partnerica za vrijeme izvođenja pokreta u Pass de deuxu (plesu udvoje). Mehanizmi nastanka ozljeda su uslijed prenaprezanja ili traumatske etiologije. Najčešće ozljede su uganuće gležnja od traumatskih i ostale koje se javljaju uslijed prenaprezanja. Prenaprezanje je najčešći uzrok ozljeda u ženskih plesača, dok u muških plesača češći uzrok je traumatska etiologija. Traumatske ozljede zahvaćaju i mlade plesače koji tek stupe u plesnu trupu i nisu navikli na intenzitet programa. Kao rekreativna aktivnost, balet danas postaje sve popularniji.Ballet is at the same time and arts and sports. The physical requirements in ballet are very unique. Pushing the limits of our own body in order to achieve elegance and aesthetics go beyond biology of the human body. The professional ballet dancers often enter in that at a very early age. Education is a long-term, arduous and requires a lot of sacrifice, work and persistence. The system selection is becoming stricter on higher levels of education. The intensity of exercise increases. Ballet requires special shoes. Ballet shoes are specially designed for dancer to stand on tiptoe with the feet in plantar flexion. Biomechanics of the body changes in dancer’s body. Initial ballet position requires flattening of physiological curve of the spine, muscle contractions of the anterior abdominal wall, arms must be in a position of natural harbour with raised neck. The legs go to external rotation of the hip with open feet to the angle of 180 ° with full extension in the knee joint. Ballet lessons consists of two parts, the exercises on a Barre and a central teaching. Exercises on Barre serve to warm up the body for the central part of the class. In the cycle of seasons one ballet company injuries happen mostly during ballet classes and on the stage. Risk factors that increase the risk of injury are certainly types of dance floor and ballet shoes. The greatest risks for injury are lower extremities and spine. In male dancers also comes to injuries of the upper extremities due to raising partner during the movements in the Pass de deux (dance for two). Mechanisms of injuries are due to overuse or traumatic aetiology.. The most common injuries are traumatic ankle sprains and others that occur due to overuse. Overexertion is the most common cause of injuries in female dancers, while in male dancers common cause is of traumatic aetiology. Traumatic injuries affect young dancers who only come into dance troupe and their body is not used to the intensity and demands of the program. As a recreational activity, the ballet has become increasingly popular

Occupational injuries in professional dancers

Balet je u isto vrijeme i umjetnost i sport. Fizički zahtjevi u baletu su veoma jedinstveni. Pomicanje granica vlastitog tijela radi postizanja elegancije i estetike nadilaze biologiju ljudskog tijela. Profesionalni plesači u svijet baleta često ulaze u vrlo ranoj dobi. Školovanje je dugotrajno, mukotrpno i zahtijeva mnogo odricanja, rada i upornosti. Sistem selekcije postaje sve stroži na višim razinama školovanja. Intenzitet vježbi raste. Balet zahtjeva posebnu obuću, tzv. špice. Špice su posebno dizajnirane papučice u kojima plesač stoji na vrhovima prstiju sa stopalima u plantarnoj fleksiji. Biomehanika tijela u plesača se mijenja. Početni baletni položaj zahtijeva izravnate fiziološke krivine kralježnice, kontrakcije mišića prednje trbušne stjenke, ruka moraju biti u položaju prirodnog luka s izdignutim vratom. Noge idu u vanjsku rotaciju iz kuka s otvorenim stopalima prema kutu od 180º s potpunom ekstenzijom u koljenom zglobu. Baletni sat sastoji se od dva dijela, vježbi na štapu i centralno izvođenje nastave. Vježbe na štapu služe zagrijavanju tijela za centralni dio sata. U ciklusu sezone jedne baletne trupe do ozljeda najviše dolazi u periodu izvođenja baletne nastave i za vrijeme nastupanja. Rizični faktori koji povećavaju rizik nastanka ozljede su svakako vrsta poda na kojem se pleše i baletne špice. Najveći rizik za pojavu ozljeda imaju upravo donji ekstremiteti i kralježnica. Kod muških plesača također dolazi do ozljeda gornjih ekstremiteta zbog podizanja partnerica za vrijeme izvođenja pokreta u Pass de deuxu (plesu udvoje). Mehanizmi nastanka ozljeda su uslijed prenaprezanja ili traumatske etiologije. Najčešće ozljede su uganuće gležnja od traumatskih i ostale koje se javljaju uslijed prenaprezanja. Prenaprezanje je najčešći uzrok ozljeda u ženskih plesača, dok u muških plesača češći uzrok je traumatska etiologija. Traumatske ozljede zahvaćaju i mlade plesače koji tek stupe u plesnu trupu i nisu navikli na intenzitet programa. Kao rekreativna aktivnost, balet danas postaje sve popularniji.Ballet is at the same time and arts and sports. The physical requirements in ballet are very unique. Pushing the limits of our own body in order to achieve elegance and aesthetics go beyond biology of the human body. The professional ballet dancers often enter in that at a very early age. Education is a long-term, arduous and requires a lot of sacrifice, work and persistence. The system selection is becoming stricter on higher levels of education. The intensity of exercise increases. Ballet requires special shoes. Ballet shoes are specially designed for dancer to stand on tiptoe with the feet in plantar flexion. Biomechanics of the body changes in dancer’s body. Initial ballet position requires flattening of physiological curve of the spine, muscle contractions of the anterior abdominal wall, arms must be in a position of natural harbour with raised neck. The legs go to external rotation of the hip with open feet to the angle of 180 ° with full extension in the knee joint. Ballet lessons consists of two parts, the exercises on a Barre and a central teaching. Exercises on Barre serve to warm up the body for the central part of the class. In the cycle of seasons one ballet company injuries happen mostly during ballet classes and on the stage. Risk factors that increase the risk of injury are certainly types of dance floor and ballet shoes. The greatest risks for injury are lower extremities and spine. In male dancers also comes to injuries of the upper extremities due to raising partner during the movements in the Pass de deux (dance for two). Mechanisms of injuries are due to overuse or traumatic aetiology.. The most common injuries are traumatic ankle sprains and others that occur due to overuse. Overexertion is the most common cause of injuries in female dancers, while in male dancers common cause is of traumatic aetiology. Traumatic injuries affect young dancers who only come into dance troupe and their body is not used to the intensity and demands of the program. As a recreational activity, the ballet has become increasingly popular

A GPU framework for parallel segmentation of volumetric images using discrete deformable models

Despite the ability of current GPU processors to treat heavy parallel computation tasks, its use for solving medical image segmentation problems is still not fully exploited and remains challenging. A lot of difficulties may arise related to, for example, the different image modalities, noise and artifacts of source images, or the shape and appearance variability of the structures to segment. Motivated by practical problems of image segmentation in the medical field, we present in this paper a GPU framework based on explicit discrete deformable models, implemented over the NVidia CUDA architecture, aimed for the segmentation of volumetric images. The framework supports the segmentation in parallel of different volumetric structures as well as interaction during the segmentation process and real-time visualization of the intermediate results. Promising results in terms of accuracy and speed on a real segmentation experiment have demonstrated the usability of the syste

Short- and Long-Term Changes in Attention, Memory and Brain Activity Following Exercise, Motor Learning, and Expertise

How humans perceive, embody, and execute actions has been an area of intense study in cognitive neuroscience, and these investigations shed light on how we adaptively learn from and interact with an ever-changing world. All of the knowledge associated with action, including sensorimotor representations, the words we use to describe them, and the memories that store this information, are represented in distributed brain regions that comprise knowledge schemas. With repeated practice or training, one can acquire a highly specialized motor repertoire that fosters even more efficient and adaptable behaviour to achieve peak performance. Using behavioural, EEG and fMRI approaches, I will present a series of investigations that evaluate the impact of short-term exercise and long-term dance practice on the development of expert knowledge schemas. In Chapters 2 and 3, I will demonstrate that activating one domain in the schema (e.g., action processing) will prime other domains (e.g., verbal attention and working memory) to induce translational performance improvements. Subsequent chapters will reveal how familiarity with a specific genre of dance influences behavioural (Chapter 3) and neurophysiological signatures of action perception, how these motor representations are coded in sensorimotor association areas (Chapters 4), and how they change with repeated practice and performance (Chapter 5). How these findings contribute to our model of expert knowledge schemas will be discussed in Chapter 6. These findings bear efficacy for the therapeutic application of exercise and dance programs to alleviate motor, cognitive and neurophysiological impairments in several clinical populations, including people with Parkinsons disease

Analysis of the backpack loading efects on the human gait

Gait is a simple activity of daily life and one of the main abilities of the human being. Often during leisure, labour and sports activities, loads are carried over (e.g. backpack) during gait. These circumstantial loads can generate instability and increase biomechanicalstress over the human tissues and systems, especially on the locomotor, balance and postural regulation systems. According to Wearing (2006), subjects that carry a transitory or intermittent load will be able to find relatively efficient solutions to compensate its effects.info:eu-repo/semantics/publishedVersio

The frequency of falls in children judo training

Purpose: Falling techniques are inseparable part of youth judo training. Falling techniques are related to avoiding injuries exercises (Nauta et al., 2013). There is not good evidence about the ratio of falling during the training in children. Methods: 26 children (age 8.88±1.88) were video recorded on ten training sessions for further indirect observation and performance analysis. Results: Research protocol consisted from recording falls and falling techniques (Reguli et al., 2015) in warming up, combat games, falling techniques, throwing techniques and free fighting (randori) part of the training session. While children were taught almost exclusively forward slapping roll, backward slapping roll and sideward direct slapping fall, in other parts of training also other types of falling, as forward fall on knees, naturally occurred. Conclusions: Judo coaches should stress also on teaching unorthodox falls adding to standard judo curriculum (Koshida et al., 2014). Various falling games to teach children safe falling in different conditions should be incorporated into judo training. Further research to gain more data from groups of different age in various combat and non-combat sports is needed

Fear of crime and victimization among the elderly participating in the self-defence course

Purpose. Self-defence training could enhance seniors´ defensive skills and fitness. There is lack of evidence about fear and concerns of seniors participating in the self-defence course. Methods. 18 elderly persons (16 female, 1 male; age 66.2, SD=5.86) participated in the self-defence course lasting 8 training units (each unit 60 minutes). Standardized tool for fear of crime and victimization analysis previously used in Euro-Justis project in the Czech Republic (2011) was used in pretest and posttest. Results. We explored the highest fear of crime by participants in their residence area after dark (mean=2,77; median=3; SD=0,80), lower fear at the night in their homes (mean=2,29; median=2; SD=0,75) and in their residence area at the daytime (mean=2,00; median=2; SD=0,77) at the beginning of the course. We noticed certain decrease of fear of crime after the intervention. Participant were less afraid of crime in their residence area after dark (mean=2,38; median=2; SD=0,77), they felt lower fear of crime at the night in their homes (mean=2,00; median=2; SD=0,48) and in their residence area at the daytime (mean=1,82; median=2; SD=0,63). Conclusions. The approach to self-defence teaching for elderly should be focused not just on the motor development, but also on their emotional state, fear of crime, perception of dangerousness of diverse situations and total wellbeing. Fear of crime analysis can contribute to create tailor made structure of the self-defence course for specific groups of citizens