1,721,026 research outputs found
Physiological demands of performance in Classical Ballet and their relationships with injury and aesthetic components
Get PDFA thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of
PhilosophyAt performance level, classical ballet is a form of high-intensity, intermittent exercise, requiring a strong aerobic foundation. Existing training methods have remained largely unchanged over the past century, resulting in poorly conditioned dancers who are prone to injury. The purpose of the thesis was to examine, through several inter-related studies, the demands of training and performance at professional level, and whether fitness levels of classical ballet dancers affect both aesthetic components of performance, and injury. All participants were either in the final year of elite vocational training or were professional dancers. Initial, observational, investigations indicated that both rehearsal and performance posed a variety of demands on different ranks of dancer within a company’s structure, and depicted daily workloads which supported previous complaints of fatigue. Before examination of fitness or performance could begin, novel tools to assess both aerobic fitness, and performance proficiency in ballet dancers were designed and tested for reliability and validity. Both tests met with test-retest reliability standards, with 95% limits of agreement of ±6.2 ml.kg.-1min-1 for the aerobic test, and ±1.5 points (out of 10) for the performance rating scale. High overall performance scores were then best predicted by high jumps of both legs and good active flexibility of the left leg (F=4.142, df=3, P=0.042). Following this, an intervention study investigated the effects of a period of supplemental fitness training, designed to enhance aerobic fitness, jump height and local muscular endurance, on the performance scores of a randomly assigned group of dancers. A control group continued with regular training. Performance scores at the outset of the study were compared to those following the intervention period. Overall scores for the intervention group increased by significantly more than those of the control group, (p=0.03), with greatest gains seen for control and skill, indicating that supplemental fitness training, specifically targeting aerobic and local muscular endurance, can help improve performance, particularly elements such as control and skill. Finally, two separate studies confirmed that low aerobic fitness and low body fat percentage were related to injury in ballet dancers. Further research needs to focus on fully ascertaining the physical demands of ballet, and whether better training dancers to meet these demands results in enhanced performance and reduction in injury
The effect of vibration training on balance and muscular performance within functionally unstable ankle populations
Get PDFA Thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Master of PhilosophyAnkle injuries are one of the most common injuries in sport, often leading to functional deficits and instability, a vicious cycle of recurrent sprains and time loss due to injury. Although research has been conducted on the best methods of treating such deficits and instability, new training methodologies are continually being sought to help improve clinical outcomes and with this comes a need for designed research to test such hypotheses. The purpose of the present research was to investigate the effect of vibration training on balance and muscle function in physically active individuals suffering self reported functional ankle instability (FAI). Stage one of the research was to initially investigate the effect of a six week whole body vibration training (WBVT) exercise routine on 38 University dancers reporting FAI. An initial assessment of the severity of the instability was done using the Cumberland Ankle Instability Tool (CAIT), to identify those who classed themselves functionally unstable but still able to participate in their chosen sport. The group was randomly arranged into one of two groups (treatment and control) and a pre/post test study was undertaken, with the control group asked to continue normal activity. The selection of participants was based on instability score from the CAIT. A larger sample of athletes was initially recruited across two accessible sports of football and dance due to access and availability. These groups then completed CAIT and where included if scoring criteria were met. The treatment group undertook six weeks of progressive vibration training on a stabile vibration system. Pre and post testing consisted of measures of static single leg balance, a Star Excursion Balance Test (SEBT) and Electromyography (EMG) of peroneus longus in demi-pointe. Results indicated a significant improvement in static balance (p = .04) and certain SEBT directions within the treatment group compared to the control group (p .05). The results of the study suggested six weeks vibration training improved certain balance parameters within FAI populations. These results although initially encouraging, identified the need for further research with not just a direct comparison between treatment and control, but a closer examination of the effect of vibration training in comparison to more classical methods of rehabilitation before it can be recommended as a serious methods of treatment for FAI. The second stage of the research involved the implementation of a new piece of rehabilitation equipment which combined a vibration unit within a wobble board (Vibrosphere TM, Sweden). The manufactures claim the combination of the two principles accelerates rehabilitation for numerous lower body injuries and disorders. This specially designed unit allowed direct analysis of the effect of the vibration component of the unit on balance and muscle function, by comparing those who used the combined vibration/wobble board and those who simply used the wobble board alone. A control group was also included to analyse any difference over time as the testing was done during a pre-season training cycle. The research consisted of 33 semi-professional footballers reporting FAI as confirmed by CAIT and taler tilt and an anterior drawer test, being randomly assigned to one of three groups; Vibration/wobble board, Wobble board alone and Control. Both Vibration/wobble board and Wobble board alone completed identical exercises on identical equipment so results could not be attributed to different equipment. The results of the study suggest a significant difference in static balance; modified SEBT and Single leg triple hop for distance between groups with the greatest improvement being within the combined vibration/wobble board group (p <.05). The results suggest the combination of vibration and wobble board improve balance and functional strength in those footballers reporting FAI compared to wobble board training alone. The precise mechanisms behind the current results are unclear. It has been suggested that it may be due to vibration having a positive effect on the stimulation of mechanoreceptors and the combination of that and unstable surface control seems to be optimal. It is difficult to compare studies but the research has highlighted certain areas for further research. The difference in static balance and SEBT scores between the dancers and footballers seems to suggest that the CAIT scores although similar may identify the need for more specific tests for each population. Also a longitudinal study is required to access injury rates following intervention and effect duration of the improvements seen
AN INVESTIGATION OF GRAND BATTEMENT DEVANT AT BARRE, CENTRE, AND IN MOTION USING KINEMATICS AND ELECTROMYOGRAPHY
Get PDFA thesis submitted in partial fulfilment of the
requirements of the University of Wolverhampton
for the degree of Doctor of PhilosophyThe purpose of this study was to examine grand battement devant in three conditions: at the barre, in the centre, and traveling. The primary focus was to consider weight transfer in the three conditions, and to examine utilisation of the trunk and lower extremity muscles. An extensive review was done in the dance science literature to determine what previous research had been done related to this subject, and to establish what preliminary work might be needed. As indicated by the literature, in order to achieve this research, it was necessary to develop a dance-specific method for the normalisation of surface electromyography data. In phase one of the research, a dance-specific portable anchored dynamometer was developed and tested. The PAD allowed for the collection of maximum voluntary isometric contractions (MVICs), which could then be used to normalise the sEMG data. In phase two of the research, the grand battement was tested in the three conditions, at the barre, in the centre, and traveling. Forty female dancers volunteered (mean age 30.0 ± 13.0 yrs, mean height 1.63 ± 0.06 m, mean mass 59.0 ± 7.4 kg, and 13.9 ± 13.3 yrs of training in ballet and/or modern dance) and were placed in three groups (Training level): beginner (n = 12), intermediate (n = 14) and advanced (n = 14). Dancers executed five grand battement devant in each of the three conditions (Condition) in randomized order. Data were collected with a 7-camera Vicon motion capture system, two Kistler forceplates, and surface electromyography (EMG), using eight muscles bilaterally. Kinematic data were analysed in three intervals: stance to battement initiation, initiation to battement peak, and peak to end. Four variables were investigated: centre of gravity of the full trunk, centre of gravity of the pelvis, centre of gravity of the upper trunk, and centre of mass. EMG data were analysed in four events: stance, initiation, peak, and end. For weight transfer, the main effect of Condition was significant for all four variables in both the x-axis and the y-axis (p < .001). There were no significant differences for Training and no significant Condition x Training interactions. Muscle use varied according to the combination of event and condition that was executed, and these differences were also influenced by the level of training of the dancer and the side of the body used. It is recommended that dance educators consider the importance of allocating sufficient time to each of the three conditions (barre, centre, and traveling), to ensure development of a variety of motor strategies and muscle activation patterns for dance practice
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Evaluation of physical fitness in relation to performance and injury severity in contemporary dance
Get PDFA thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of PhilosophyDance has attracted little scientific interest on the effects of physical fitness improvements on performance and injury severity, particularly with respect to contemporary dance. The main aims of the current work were: a) to observe the physical demands of dance performance; b) to develop a reliable dance-specific performance tool; c) to assess the association between selected physical fitness parameters and performance in contemporary dance by using a new reliable method (AC test); d) to assess selected physical fitness parameters in relation to injury severity in contemporary dance; e) to study the effects of increased fitness parameters on performance through a randomized controlled trial. A total of 50 performances, performed by 20 dancers, were monitored by using a portable accelerometers (SWA armbands) and heart rate monitors while 45 performances in DVDs were video analysed. Six dancers and two dance teachers were recruited to test a newly developed performance tool. A sample made of 41 dancers were recruited and assessed for aerobic fitness (DAFT), lower body muscular power (jump height test), upper body muscular endurance (press-ups test), flexibility (active and passive hip ROM), body composition (skinfolds), performance (n=17) and injury severity (n=16). In order to investigate the effects of the supplementary fitness training on performance, 24 of the total 41 dancers, were randomly assigned to either an intervention (n=12) or control (n=12) group. The intervention group undertook a specifically designed exercise-training programme (circuit and WBV training) lasting six weeks. Both groups were re-tested for physical fitness levels and performance at the end of the intervention period. Results revealed that performance intensities varied from light to moderate while these were observed with the use of pliés and jumps as well as lifting other dancers. Based on the seven most frequently used criteria by selected pre-professional contemporary dance institutions and companies, a novel performance tool (AC tool) was developed with an inter-rater reliability of r=0.96. There was a significant correlation between aesthetic competence (AC) scores and jump ability (r=0.55) and press-ups (r=0.55), respectively. Stepwise backward multiple regression analysis revealed that the best predictor of AC was press-ups (R2=0.30, p=0.03, 95% confidence intervals=0.11–1.34). Univariate analyses also revealed that the interaction of press-ups and jump ability improved the prediction power of AC (R2=0.44, p=0.004, 95% confidence intervals=0.009–0.04). Pearson’s correlation coefficients detected significant negative correlations between the mean score recorded for injury severity (expressed as TDO) and lower body muscular power (r=-0.66; p=0.014); backward regression analysis also revealed that, from all studied parameters, the strongest predictor of TDO was lower body muscular power (p=0.014). For the intervention group repeated measures ANOVA revealed significant increases (pre vs. post) in aerobic fitness (p<0.05), lower body muscular power (p<0.05), upper body muscular endurance (p<0.05) and performance (p<0.05). Linear regression analyses indicated that the only significant predictor of AC was aerobic capacity (F=7.641; p=0.03); the interaction of press-ups and aerobic capacity (F=6.297; p=0.036), and lower body muscular power with aerobic capacity (F=5.543; p=0.05) demonstrated an improved prediction power. These results show that the observed contemporary dance performance is an intermittent type of activity of moderate intensity. Given the reliability of the AC tool, it is concluded that upper body muscular endurance and jump ability best predict AC of contemporary dancers. Reduced lower body muscular power is associated with increased severity of injuries. Finally, supplementary exercise training significantly increases lower body muscular power, upper body muscular endurance and aerobic fitness, which in turn are beneficial to improve AC of contemporary dancers
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