1,720,959 research outputs found
Performance sports engineering: improving knowledge of human underwater undulatory swimming
No full textUnderwater Undulatory Swimming (UUS), performed fully submerged following a dive or push from the wall in swimming, can be exploited to gain a competitive advantage in races. Athletes can travel underwater for up to 30 % of the race while performing an undulatory motion, benefitting from a reduction of resistive forces. The undulatory motion consists of a wave which propagates along the body, from the fingertips to the toes. As this wave moves along the body its amplitude increases, accelerating the fluid downstream to generate propulsive forces which propel the swimmer forward. This swimming technique mimics the locomotion of marine mammals. This collaborative presentation highlights the work undertaken during two closely related UK Sports Institute funded PhD projects. The kinematic data acquisition process using three-dimensional optoelectronic motion capture will be presented, along with the joint centre reconstruction methods. A novel two-dimensional implicit-LES computational fluid dynamics methodology will also be introduced. Examples of applications given by the speakers will include an estimation of error within the kinematic capture domain, the efficacy of training practices in UUS skill development, and a case study on the impact of kinematic modification on UUS force generation of a regional-level swimmer
Efficacy of training practices to develop underwater fly kick performance
No full textThe underwater phase is a critical aspect of the swimming race where swimmers can gain a competitive advantage. A literature review revealed several areas lacking investigation, which would develop the body of knowledge surrounding underwater fly kick. Despite previous studies highlighting determinant factors of underwater fly kick performance, there is a lack of evidence available as to how to improve these aspects and coaches’ current practices not considered. This thesis aimed to assess the efficacy of short and long-term interventions in the development of underwater fly kick skills. The development of a three-dimensional motion capture methodology for the quantification of underwater fly kicking kinematics was detailed. Kinematics obtained from three and two-dimensional methods were compared, revealing differences in measured angles at every joint between 0.35 and 18.35 degrees. Correlation analysis indicated that out-of-plane motion, up to 36.69 degrees range of transverse plane and 19.26 degrees frontal plane motion and at the hip, affects the sagittal plane angle measured and is overlooked in two-dimensional analysis. A comparison of underwater fly kicking kinematics in eight male athletes (FINA points between 600 and 923) highlighted the importance of hip extension in maximising up-beat vertical toe velocity (r = .738, p = .037). Highly skilled athletes produced increased ankle only motion in coordination between transverse plane motion of the hip and ankle (r = .810, p = .015), and increased peak rotational velocity at the hip and ankle (r = .810, p = .015 and r = .738, p = .037 respectively). The current perceptions and practices of 56 coaches surrounding underwater fly kick development were explored. Coaches are considering complex concepts presented within the literature such as whole body coordination but lack the resource to implement best practices for skill development into training. The efficacy of common interventions were then assessed. The techniques of five elite male swimmers (FINA points: 884 41) in differing orientations were compared. A decreased up-beat duration (p = .042) indicated that supine swimming may facilitate increased kicking symmetry. However, this change in technique may be brought about through detrimental alterations; a lower kick frequency and reduced down-beat toe velocity. Two short-term interventions were then assessed in skilled male athletes (FINA points: 697 81); vertical kicking and resisted training. Vertical kicking improved kick symmetry, but the 4 % increase in up-beat duration diminished post across post intervention trials (p = .011). A resisted training intervention produced a 6 % increased swimming velocity post intervention (p = .019), but may have negative consequences upon technique through reduced hip motion and increased oscillation at the trunk and shoulder. Finally, the effects of a four-week skill acquisition intervention were assessed in a group of skilled male swimmers (FINA points: 681 62). Initially focussing on exploration of movement patterns, the intervention developed towards stabilising performance for competition. This intervention elicited improved performance through increased average and peak swimming velocity (p = .038 and .019 respectively) and decreased up-beat duration and symmetry between up and down-beat toe velocities (p = .022 and p = .002 respectively), enabling longer term development of techniques. Work packages within this thesis provide insights into the efficacy of current training practices, providing evidence for longer-term structured implementation of skill training theory driven practices in underwater fly kick coaching
Coaching Practices to Develop Underwater Fly Kick performance in Swimming Training
No full textThis study assessed current swimming coaching practices surrounding underwater fly kick. Ten elite coaches completed face-to-face interviews, and 56 coaches completed an online survey. Coaches use a range of methods both in and out of the pool to develop key aspects of fly kick. Sixty eight percent of coaches reported they do not have access to resources that would aid with their ability to develop fly kick. Results show that coaches are considering a range of variables when attempting to improve fly kick, with the three most important highlighted as kick frequency, kick symmetry and coordination. Coordination is reported as the variable presenting the greatest difficulties when coaching due to athlete's physical restrictions and individual differences, as well as difficulties in coaching proprioception. Coaches are using a variety of resources to inform their approaches in underwater fly kick, but report coach certification and education resources as having the lowest influence on their coaching methods. Generally, results indicate a lack of skill acquisition knowledge and education in underwater fly kick. Reflecting upon coaches’ views and approaches allows for further research to develop understanding of interventions used to improve fly kick, and aids with the transfer of key research findings into practice.</p
Dataset to support the paper 'Coaching Practices to Develop Underwater Fly Kick Performance in Swimming Training'
No full textThis data supports the publication 'Coaching Practices to Develop Underwater Fly Kick Performance in Swimming Training'. in the International Journal of Sports Science and Coaching
Provided are the combined interview and survey short answer questions (Combined_ShortAnswer.sav), and the coding manual for long answer question (Coding_Manual_LongAnswer.docx). Full written responses are not included in this dataset to ensure anonymity of participants.
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Data collected in relation to the thesis 'Efficacy of training practices to develop underwater fly kick performance'
No full textThis data supports the doctoral Thesis 'Efficacy of Training Practices to Develop Underwater Fly Kick Performance' submitted to the University of Southampton.
Provided are the data sets underpinning each key chapter.
Chapter Three: Contained are both the pre and post assessment key variables for fatigue analysis (ChapterThree_Fatigue.sav) and the error related coordinated (ChapterThree_ErrorCoordinates.xlsx).
Chapter Four: Contained are the key metrics measured using two and three-dimensional methods (ChapterFour_KeyMetrics.sav) and the angular kinematics related to both methodologies (ChapterFour_Kinematics.xlsx).
Chapter Five: Contained are the key metrics (ChapterFive_KeyMetrics.sav) and angular kinematics (ChapterFive_Kinematics.csv).
Chapter Six: Contained are the combined interview and survey short answer questions (Combined_ShortAnswer.sav), and the coding manual for long answer question (Coding_Manual_LongAnswer.docx). Full written responses are not included in this dataset to ensure anonymity of participants.
Chapter Seven: Contained are the key metrics (ChapterSeven_KeyMetrics.sav) and angular kinematics (ChapterSeven_Kinematics.csv) measured in prone and supine orientations.
Chapter Eight: Contained are the key metrics and angular kinematics related to vertical kicking and resisted training interventions (ChapterEight_Results.xlsx).
Chapter Nine: Contained are the key metrics (ChapterNine_KeyMetrics.sav) and angular kinematics (ChapterNine_Kinematics.csv) related to measurements taken pre and post a four-week intervention. </span
Dataset to support the paper 'Error assessment of a three dimensional underwater motion capture methodology'
No full textThis data supports the publication 'Error Assessment of a Three Dimensional Underwater Motion Capture Methodology' in a currently unspecified journal.
Provided are the coordinate data for the calibrated volume (CalibrationCoordinates.csv) and coordinate data for all related trials (SystematicSectioning.csv, SystematicLength.csv, RandomOne.csv, and RandomTwo.csv).</span
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
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