• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3514
  • 1191
  • 878
  • 609
  • 309
  • 147
  • 101
  • 87
  • 60
  • 57
  • 53
  • 53
  • 52
  • 52
  • 52
  • Tagged with
  • 9164
  • 1312
  • 1294
  • 1067
  • 950
  • 802
  • 794
  • 785
  • 729
  • 641
  • 630
  • 630
  • 628
  • 603
  • 564
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Factors Affecting the Performance Levels of Risk Management Behaviors of Florida High School Athletic Directors

Unknown Date (has links)
The purpose of this study was twofold: (1) to measure the degree to which Florida High School athletic directors utilize risk management within their athletic program and (2) to determine whether selected demographic factors (i. e. undergraduate major, years of experience as Athletic Director, level of education, etc.) have an effect on the performance levels of these risk management behaviors. A 42-item survey was used to collect data related to specific risk management behaviors and 12 demographic items. Descriptive statistics were calculated for each factor on the demographic section of the survey, the composite scores for each of the individual items on the survey, for all of the items combined (grand mean), and for the composite scores of each conceptual area (i.e. medical concerns, facilities, etc.). A one-way ANOVA was then used to test for significance among the independent variables (selected demographic factors) and dependent variables (risk management behavior scores of the (1) grand mean, (2) conceptual area means, and (3) individual item means). Results of the study suggest that (1) the risk management behaviors being performed within Florida High School athletic departments are being performed on a rather consistent basis and that (2) the two primary factors that influenced FHSAA athletic director's performance of risk management behaviors were current employment status and current coaching status. / A Dissertation submitted to the Department of Sport Management, Recreation Management and Physical Education in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Degree Awarded: Summer Semester, 2004. / Date of Defense: April 22, 2004. / Sports, Liability, Tort, Law, Sports Law, Negligence, Athletics, Sport, NCAA, NAIA / Includes bibliographical references. / Annie Clement, Professor Directing Dissertation; Tonya Toole, Outside Committee Member; E. Newton Jackson, Jr., Committee Member; B. Cecile Reynaud, Committee Member.
112

Examining the Values Associated with Spectator Sports and the Relationships Between the Values and Sport Spectator Behavior

Unknown Date (has links)
The dissertation had two major research purposes. The first purpose was to explore what values may be associated with spectator sports. This purpose was completed by using qualitative inquiry and conducting a review of literature. The second purpose was to examine the relationships between personal values and sport spectator behavior. Sport spectator behavior included spectator sport consumption and sport spectator experiences. This purpose was completed by administering a questionnaire and conducting statistical analyses (for example, descriptive analyses, MANOVA, cluster analyses, stepwise multiple regression, and confirmatory regression analyses). In general, this dissertation adopted a mixed research method design including qualitative and quantitative methods. A qualitative study was conducted to examine values individuals associate with spectator sports. Prior studies of values in sport settings have been primarily conceptual discussions (e.g., Duncan, 1983; Wann, Melnick, Russell, & Pease, 2001) and have focused on participation rather than spectatorship (e.g., Lee, Whitehead, & Balchin, 2000; Simmons & Dickinson, 1986; Wankel & Berger, 1990). Research with spectator sports has investigated fan motivations for attending sports rather than general values associated with spectator sports (e.g., Milne, & McDonald, 1999; Trail, & James, 2001). The current study is an initial step examining the values individuals associate with spectator sports. The study utilized interviews and focus groups and had four progressive phases for triangulation, transferability and constant comparative assessment. The finding suggested ten value types associated with spectator sports: Enjoyment, Sociability, Identity, Status, Moral, Spirituality, Epistemic, Aesthetics, Ritual, No or negative values. Using existing value measures (Kahle, 1983; Maslow, 1970; Rokeach, 1973; Schwartz, 1992, 1996), a pilot survey was conducted to specify 28 individual values which were considered more relevant to spectator sports. A main study was then conducted by using a questionnaire with 28 value measures, 6 modes of spectator sport consumption and 10 experience items. The first group of hypotheses examined whether personal values predicted spectator sport consumption. The results showed significant results, but the direction of associations varied. Sixteen personal values had positive associations with spectator sport consumption; 7 had negative associations with spectator sport consumption; 5 had mixed results. The second group of hypotheses examined whether personal values predicted expected sport spectator experiences. Twenty personal values supported the hypotheses; five values had the results opposite to the hypotheses; two values had mixed results; the value, DEVOUT did not have significant result. The results suggested directions for revision of the ten-value type framework derived from the qualitative inquiry. The results also indicated that the corresponding relationships between some of the individual values and value types associated with spectator sports require further clarification. Different from the results of prior research in fan motivations, the results of this dissertation show that it is likely that people might experience something relevant to some values through spectator sport consumption but did not actively associate the values with spectator sports. In other words, people might be motivated to consume spectator sports in some occasions, but this did not mean that the motivation is a constant value associated with spectator sports. Future research is required to provide more evidence to support this conjecture. The results provide implications for theory in sport consumer behavior to explain spectator sport behavior more thoroughly. The results also provide useful information for sport marketers, sponsors, and policy makers to design their promotion activities, proposals, and policies by using the values as themes. Future research should examine how different sports and cultures influence the associations between personal values and spectator sports. Value-based attitudes might be developed for each value type to help clarify the relationships among values, motives, and attitudes toward spectator sports. The development of attitudes can also enhance the prediction effects of values on spectator sport consumption. By conducting spectator sport value research, it is hoped that attributes of spectator sports can be identified or created to help sport marketers design sporting events to meet the desires of broad potential consumers. / A Dissertation submitted to the Department of Sport Management, Recreation Management, and Physical Education in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Degree Awarded: Fall Semester, 2007. / Date of Defense: August 31, 2007. / Spectator Sports, Value Types, Sport Spectator Behavior, Sport Spectator Experiences, Spectator Sport Consumption, Personal Values / Includes bibliographical references. / Jeffrey James, Professor Directing Dissertation; Bruce T. Grindal, Outside Committee Member; Felipe Korzenny, Committee Member; Leisa R. Flynn, Committee Member; Aubrey Kent, Committee Member.
113

A Hypothetical Universal U.S. Sports Betting Market: Modeling the U.S. Market Using Australian Panels

Bagamery, Jack January 2016 (has links)
Thesis advisor: Father Richard McGowan / In the United States, gambling on sports is a widespread and popular activity. Yet, the extent of that popularity is largely unknown because the practice is illegal, with the exception of a handful of states. To determine the scale of this market, I construct a series panel regression models that explain the size of the legal sports betting market in Australia using continuous macroeconomic and behavioral variables in addition to dummy variables signaling regulatory shifts. Using the relationships between these variables and sports betting expenditure, I will estimate the size of the United States market on a state-by-state basis. After sizing the U.S. market, I will briefly discuss the key finding of the synergistic relationship between sports betting and Internet as well as the inevitable tradeoffs between the economic benefits and consequences of legalization. / Thesis (BS) — Boston College, 2016. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Departmental Honors. / Discipline: Economics. / Thesis advisor:
114

Isokinetic profile of trunk muscles in athletes: a quantitative study with correlation to sports.

January 1994 (has links)
by John Ping San Wong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 84-90). / ABSTRACT / Chapter I. --- INTRODUCTION --- p.1 / Chapter 1.1 --- General introduction --- p.1 / Chapter 1.2 --- Operational definitions --- p.5 / Chapter 1.2.1 --- Isokinetic parameters being investigated --- p.5 / Chapter 1.2.2 --- Elite athletes --- p.6 / Chapter 1.2.3 --- Non-athletes --- p.6 / Chapter 1.2.4 --- Fast twitch and slow twitch muscle fibres --- p.7 / Chapter 1.3 --- Assumptions --- p.7 / Chapter 1.4 --- Limitation and delimitation --- p.8 / Chapter 1.4.1 --- Genetic factor --- p.8 / Chapter 1.4.2 --- Sex factor --- p.8 / Chapter 1.4.3 --- Age factor --- p.8 / Chapter 1.4.5 --- Body mass factor --- p.9 / Chapter II. --- LITERATURE REVIEW --- p.11 / Chapter 2.1 --- Dynamic control of trunk extension and flexion --- p.11 / Chapter 2.1.1 --- Trunk flexion --- p.11 / Chapter 2.1.2 --- Trunk extension --- p.12 / Chapter 2.2 --- Dynamic stabilizers in the movement of trunk extension and flexion --- p.12 / Chapter 2.2.1 --- Trunk flexion --- p.12 / Chapter 2.2.2 --- Trunk extension --- p.13 / Chapter 2.3 --- Importance of trunk muscle strength to sports performance --- p.13 / Chapter 2.4 --- Importance of trunk muscle strength in injury prevention --- p.16 / Chapter 2.5 --- Measurement of trunk muscle characteristics --- p.18 / Chapter 2.5.1 --- Isometric contraction --- p.19 / Chapter 2.5.2 --- Concentric isotonic contraction --- p.19 / Chapter 2.5.3 --- Isokinetic contraction --- p.20 / Chapter 2.5.3.1 --- Reliability and validity --- p.20 / Chapter 2.5.3.2 --- Advantage --- p.21 / Chapter 2.5.4 --- Methods that had been used for quantification of trunk strength --- p.22 / Chapter 2.6 --- Isokinetic trunk muscular characteristics for sports --- p.25 / Chapter 2.7 --- Sport specific muscle characteristics profile --- p.26 / Chapter 2.8 --- Summary --- p.27 / Chapter III. --- MATERIAL AND METHOD --- p.29 / Chapter 3.1 --- Project design --- p.29 / Chapter 3.1.1 --- Subject --- p.29 / Chapter 3.1.2 --- Equipment --- p.31 / Chapter 3.1.3 --- Procedures --- p.32 / Chapter 3.2 --- Data analysis --- p.34 / Chapter 3.3 --- Summary --- p.34 / Chapter IV. --- RESULT --- p.35 / Chapter 4.1 --- Physical characteristics of the subjects --- p.35 / Chapter 4.2 --- Trunk extension and flexion isokinetic test result --- p.35 / Chapter 4.2.1 --- Non-athletic group --- p.35 / Chapter 4.2.2 --- Badminton group --- p.36 / Chapter 4.2.3 --- Squash group --- p.37 / Chapter 4.2.4 --- Cycling group --- p.38 / Chapter 4.2.5 --- Rowing group --- p.38 / Chapter 4.2.6 --- Canoeing group --- p.39 / Chapter 4.3 --- Summary --- p.39 / Chapter V --- DISCUSSION --- p.58 / Chapter 5.1 --- Isokinetic performance in Non-athletic group --- p.59 / Chapter 5.2 --- Difference between athlete categories --- p.61 / Chapter 5.2.1 --- Badminton --- p.62 / Chapter 5.2.2 --- Squash --- p.53 / Chapter 5.2.3 --- Cycling --- p.63 / Chapter 5.2.4 --- Rowing --- p.64 / Chapter 5.2.5 --- Canoeing --- p.65 / Chapter 5 .3 --- Strength imbalances and back problem --- p.65 / Chapter 5 .4 --- The discrepancy of the Cybex test --- p.70 / Chapter 5.5 --- The methodology - Control of Subjects --- p.71 / Chapter VI. --- CONCLUSION --- p.73 / APPENDIX --- p.74 / REFERENCES --- p.84
115

Isokinetic muscular profiles among Hong Kong elite male athletes.

January 1991 (has links)
by Raymond Chi Hung So. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1991. / Includes bibliographical references (leaves 152-166). / ABSTRACT / Chapter I. --- INTRODUCTION --- p.1 / Chapter 1.1 --- GENERAL INTRODUCTION --- p.1 / Chapter 1.2 --- BACKGROUND INFORMATION --- p.1 / Chapter 1.2.1 --- MUSCLE CHARACTERISTICS --- p.1 / Chapter 1.2.1.1 --- Muscle strength --- p.1 / Chapter 1.2.1.2 --- Muscle speed of contraction --- p.3 / Chapter 1.2.1.3 --- Muscle endurance --- p.3 / Chapter 1.2.2 --- MUSCLE CHARACTERISTICS EVALUATION --- p.4 / Chapter 1.2.2.1 --- Method of evaluation --- p.4 / Chapter 1.2.2.2 --- Sports specific muscle characteristics --- p.6 / Chapter 1.3 --- RESEARCH HYPOTHESIS --- p.8 / Chapter 1.4 --- OPERATIONAL DEFINITION --- p.9 / Chapter 1.4.1 --- FAST TWITCH AND SLOW TWITCH MUSCLE FIBERS --- p.9 / Chapter 1.4.2 --- ISOKINETIC PARAMETERS BEING INVESTIGATED --- p.10 / Chapter 1.4.3 --- ELITE ATHLETE --- p.12 / Chapter 1.4.4 --- NORMAL YOUNG ADULT --- p.12 / Chapter 1.5 --- ASSUMPTION --- p.12 / Chapter 1.6 --- LIMITATION AND DELIMITATION --- p.13 / Chapter 1.6.1 --- GENETICS FACTOR --- p.13 / Chapter 1.6.2 --- SEX FACTOR --- p.13 / Chapter 1.6.3 --- AGE FACTOR --- p.14 / Chapter 1.6.4 --- BODY MASS FACTOR --- p.15 / Chapter 1.7 --- SIGNIFICANCE OF THIS STUDY --- p.15 / Chapter II. --- LITERATURE REVIEW --- p.17 / Chapter 2.1 --- IMPORTANCE OF MUSCLE STRENGTH TO SPORTS PERFORMANCE --- p.17 / Chapter 2.2 --- IMPORTANCE OF MUSCLE STRENGTH IN SPORTS INJURY PREVENTION --- p.18 / Chapter 2.3 --- MEASUREMENT OF MUSCLE CHARACTERISTICS --- p.20 / Chapter 2.3.1 --- ISOMETRIC CONTRACTION --- p.21 / Chapter 2.3.2 --- CONCENTRIC ISOTONIC CONTRACTION --- p.21 / Chapter 2.3.3 --- ISOKINETIC CONTRACTION --- p.23 / Chapter 2.3.3.1 --- Basic concept --- p.23 / Chapter 2.3.3.2 --- Reliability and validity --- p.24 / Chapter 2.3.3.3 --- Advantage --- p.26 / Chapter 2.4 --- ISOKINETIC MUSCULAR CHARACTERISTICS FOR DIFFERENT SPORTS --- p.27 / Chapter 2.5 --- RELATION OF ISOKINETIC MUSCULAR CHARACTERISTICS TO THE SPORT SUCCESS --- p.30 / Chapter 2.6 --- ISOKINETIC PARAMETERS BEING INVESTIGATED --- p.33 / Chapter 2.6.1 --- "TORQUE ACCELERATION ENERGY, AVERAGE POWER AND TOTAL WORK" --- p.34 / Chapter 2.6.2 --- ANTAGONIST TO AGONIST MUSCLE RATIO --- p.35 / Chapter 2.7 --- SPORTS SPECIFIC MUSCLE CHARACTERISTICS PROFILE --- p.37 / Chapter 2.8 --- SUMMARY --- p.38 / Chapter III. --- MATERIAL AND METHOD --- p.39 / Chapter 3.1 --- PROJECT DESIGN --- p.39 / Chapter 3.1.1 --- SUBJECT --- p.39 / Chapter 3.1.2 --- EQUIPMENT --- p.40 / Chapter 3.1.2.1 --- Cybex II+ machine --- p.40 / Chapter 3.1.2.2 --- Cybex II+ measurement characteristics --- p.42 / Chapter 3.1.3 --- THE PROCEDURE OF STUDY --- p.44 / Chapter 3.1.3.1 --- Test protocol --- p.44 / Chapter 3.1.3.2 --- Testing procedure --- p.47 / Chapter 3.2 --- DATA ANALYSIS --- p.49 / Chapter 3.3 --- SUMMARY --- p.50 / Chapter IV. --- RESULT --- p.51 / Chapter 4.1 --- PHYSICAL CHARACTERISTICS OF THE SUBJECT --- p.51 / Chapter 4.2 --- ISOKINETIC TEST RESULT --- p.52 / Chapter 4.2.1 --- KNEE EXTENSION AND FLEXION --- p.52 / Chapter 4.2.2 --- ANKLE PLANTAR AND DORSI-FLEXION --- p.54 / Chapter 4.2.3 --- SHOULDER EXTENSION AND FLEXION --- p.56 / Chapter 4.2.4 --- SHOULDER HORIZONTAL ABDUCTION AND ADDUCTION --- p.59 / Chapter 4.2.5 --- ELBOW EXTENSION AND FLEXION --- p.60 / Chapter 4.3 --- SUMMARY --- p.62 / Chapter 4.4 --- DATA RESULTS --- p.64 / Chapter V. --- DISCUSSION --- p.90 / Chapter 5.1 --- THE INTERPRETATION AND APPLICATION OF RESULTS --- p.90 / Chapter 5.1.1 --- KNEE EXTENSION AND FLEXION --- p.90 / Chapter 5.1.2 --- ANKLE PLANTAR AND DORSI-FLEXION --- p.107 / Chapter 5.1.3 --- SHOULDER EXTENSION AND FLEXION --- p.111 / Chapter 5.1.4 --- SHOULDER HORIZONTAL ABDUCTION AND ADDUCTION --- p.121 / Chapter 5.1.5 --- ELBOW EXTENSION AND FLEXION --- p.126 / Chapter 5.2 --- THE DISCREPANCY OF THE CYBEX TEST --- p.129 / Chapter 5.3 --- THE METHODOLOGY --- p.130 / Chapter 5.3.1 --- CONTROL OF SUBJECTS --- p.130 / Chapter 5.3.2 --- CONTROL OF THE DOMINANT LOWER EXTREMITY --- p.132 / Chapter VI. --- CONCLUSION --- p.133 / Chapter VII. --- APPENDICES --- p.137 / Chapter VIII. --- REFERENCES --- p.152
116

The concern of a nation's face: evidence in the Chinese press coverage of sports.

January 1989 (has links)
by Karina Lam Wai-ling. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1989. / Includes bibliographical references (leaves 144-151).
117

Physiotherapy goal setting in anterior cruciate ligament rehabilitation : an exploration of training, practice and beliefs

Alexanders, Jenny January 2018 (has links)
Despite the growing interest into the role of physiotherapists providing psychological interventions within anterior cruciate ligament (ACL), literature surrounding goal setting practices within this field is minimal. The main purpose of this research was to explore physiotherapists' approaches, training and beliefs into goal setting practices used within ACL rehabilitation. The thesis consisted of seven chapters, two of which were empirical studies. The empirical chapters aimed to gain further insight into physiotherapists understanding on the psychological aspects of patients following ACL surgery, theoretical knowledge of goal setting, experiences of implementing goals, training received on goal setting and future training needs. Study four involved a UK cross sectional online survey of one hundred and twenty four physiotherapists (N=124). The survey provided an insight of perceptions and goal setting approaches used within ACL rehabilitation. These findings were further explored in study five which involved a UK semi-structured interview study including twenty four physiotherapists (N=24), using an inductive approach. Study five provided a much deeper understanding in to physiotherapist's goal setting practices, training and experiences within ACL rehabilitation and also revealed issues surrounding the initial consultation process. The research findings were conceptualised into a theoretical, innovative goal setting model. The goal of this model is to outline a multi-phase conceptual model of an appropriate ACL rehabilitation goal setting strategy for physiotherapists in an attempt to guide both practice, teaching and research.
118

The effects of acute exercise and nutritional interventions on postprandial lipid metabolism

O'Doherty, Alasdair Fraser January 2017 (has links)
Raised postprandial triglycerides (TG) is an independent risk factor for cardio-metabolic disorders. This is due, in part, to the increases in circulating remnant lipoproteins after TG have been transported for storage or hydrolysis. Raised TG, are also associated with an atherogenic lipoprotein phenotype (High TG, low high-density lipoprotein cholesterol (HDL-c) and small, dense low-density lipoprotein (LDL) particles). In addition, elevated TG contribute to ectopic storage of fatty acids in liver, adipose and muscle tissues, contributing to insulin resistance in all three tissues and consequent metabolic dysregulation. It is therefore paramount to prevent frequent and prolonged exposure to raised TG in the postprandial period, particularly in groups who are at increased risk of cardio-metabolic disease. The dyslipidaemic component of cardio-metabolic health can be inferred by assessing the capacity to breakdown and clear TG from circulation after high fat ingestion using an oral fat tolerance test (OFTT). The OFTT can also be used to assess the efficacy of interventions targeting reductions in postprandial TG. Exercise and nutritional interventions have been shown to alter postprandial TG excursions and provide insight in to underlying mechanisms of postprandial lipid metabolism. However, there are several topics within this area of research that require further clarification. These topics have been addressed within this thesis. The first experimental chapter of this thesis (chapter 3) aimed to investigate the repeatability of an OFTT (75g fat, 22g carbohydrate, 14g protein) designed to meet recommendations from an expert panel statement. This study also aimed to evaluate the repeatability of the postprandial response to an OFTT preceded by 1 hour of acute moderate intensity exercise (cycling at a work rate eliciting 90% oxygen consumption anaerobic threshold). After an overnight fast, 11 healthy adult male participants consumed OFTT meals on 4 separate occasions; 2 preceded by rest and 2 preceded by exercise. TG area under the curve (AUC) was calculated for each test and compared to the repeat condition using non-parametric Bland-Altman analysis. The 4-hour OFTT was repeatable in the rest condition, with 9 of 10 repeat measurements falling within ±15% of the median TG AUC (predefined as the upper limit of acceptable error). However, in the exercise condition repeatability was poor with only 2 of 11 repeat measurements falling within 15% of the median TG AUC. Adult offspring of type 2 diabetics (OT2D) show irregular TG responses to OFTT with high or low carbohydrate content, compared to healthy controls. Prior acute aerobic exercise may favourably influence these postprandial responses in OT2D. This feasibility study (Chapter 4) aimed to investigate the effects of carbohydrate content and acute exercise on TG AUC after OFTT in OT2D. On 4 separate days, 8 adult male OT2D ingested OFTTs with low (HFLC; 75g fat, 22g carbohydrate, 14g protein) or high (HFHC; 75g fat, 95g carbohydrate, 14 g protein) carbohydrate content. Participants rested or exercised (1-hour moderate intensity; 90% oxygen consumption at anaerobic threshold) the day before each OFTT. Recruitment to the single centre was slow, but participant adherence to the study was good. There were large effect sizes for lower TG AUC and incremental AUC (iAUC) in the HFHC with prior exercise. Insulin AUC was higher in HFHC conditions and there was a large effect size for lower insulin AUC in the exercise conditions. Given the large effect sizes observed for the effects of prior acute exercise on postprandial TGs, an adequately powered multi-centre study was deemed to be relevant and feasible. Consumption of strawberries appears to be beneficial in attenuating the postprandial lipaemic response to OFTT due to the high polyphenol content within strawberries. The mechanisms of this attenuation in postprandial lipaemia appear to be different from the mechanisms involved in exercise induced reductions in postprandial lipaemia. However, the combined effects of exercise and strawberry interventions in reducing postprandial lipaemic responses to OFTT has not been investigated. The final experimental chapter (Chapter 5) aimed to evaluate the combined effects of acute exercise and strawberry consumption on postprandial responses to OFTT (73g to 74g fat, 32g to 33g carbohydrate, 11g to 12g protein). On 4 separate days, ten overweight/obese males ingested OFTTs with 25g freeze dried strawberries or a placebo. Participants rested or exercised (40 minutes submaximal high intensity exercise, HIIE) the day before each OFTT. There was a 20% reduction in TG AUC in the exercise conditions and no differences in TG AUC in the strawberry conditions. This thesis offers key contributions to postprandial lipid metabolism research. First, the OFTT recommended by an expert panel statement is repeatable. Second, the variability observed in postprandial responses to OFTT with immediate prior exercise may explain the inconsistencies within the literature. Third, acute exercise showed a substantive effect in reducing TG AUC and iAUC with high carbohydrate OFTT in adult OT2D. These improvements could be explained by acute improvements in insulin sensitivity, however, a further adequately powered study is required to support the findings of this feasibility study. Finally, acute HIIE appears to be an effective strategy to reduce postprandial TG, but strawberry intake does not appear to improve postprandial TG.
119

The utility of PlayerLoad™ in soccer : an examination of the reliability, validity, determinants and the within match patterns

Barrett, Stephen Mark January 2016 (has links)
The aim of the thesis was to examine the utility of tri-axial accelerometer data (PlayerLoad™) during soccer, including its reliability, validity, and determinants, with special reference to potential implications for fatigue management and injury risk. The aims of the first experimental study (chapter 3) were to: 1) establish the test-retest reliability oftri-axial accelerometer data during a standardized bout of treadmill running; 2) examine the effect of accelerometer location upon PlayerLoad™ data; and 3) investigate the convergent validity of Player Load™ using heart rate and rate of pulmonary oxygen uptake (V0₂) as criterion measures of exercise intensity. Forty-four team-sports players performed two standardized incremental treadmill running tests (7-16 km·h⁻¹) 7 d apart. Players' V0₂ (n=20), heart rate (n=44), and tri-axial accelerometer data (n=44) were measured at both the scapulae (SCAP) and at the centre of mass (COM). A cumulative vector magnitude (PlayerLoad™ [PLvM]) together with individual-component planes of PlayerLoad™ (anterior-posterior PlayerLoad™ [PLAP ], medial-lateral PlayerLoad™ [PLML] and vertical Player Load™ [PLv]) were examined. PlayerLoad™ and its individual planes showed moderate to high test-retest reliability (ICC: 0.80-0.97; CV: 4.2-14.8%) at both unit locations. PlayerLoad™ was significantly higher at COM versus scapulae (223.4 ± 42.6 vs. 185.5 ± 26.3 au; p = 0.001). The percentage contributions of individual planes to PlayerLoad™ were higher for PLML at the COM (scapulae: 20.4 ± 3.8%; COM: 26.5 ± 4.9%; p = 0.001), but lower for PLv (scapulae: 55.7 ± 5.3%; COM: 49.5 ± 6.9%; p = 0.001). Between-subject correlations between PlayerLoad™ and V0₂, and between PlayerLoad™ and heart rate, were trivial to moderate (r = -0.43 to 0.33), whereas within-subject correlations were nearly perfect (r = 0.92 to 0.98). PlayerLoad™ had a moderate to high degree of test-retest reliability and demonstrated convergent validity with measures of exercise intensity on an individual basis. However, caution should be applied in making between-athlete contrasts in loading, and when using recordings from the scapulae to identify lower-limb movement patterns. Further research is required to investigate if multidirectional movements observed in team sports, such as soccer, effect the reliability of PlayerLoad™ Experimental study 2 (Chapter 4) aimed to examine the PLvM and the individual planars response to a 90-min laboratory controlled soccer match-play simulation. Five semi-professional and 15 university soccer players completed three trials (one familiarisation, two experimental) of SAFT⁹⁰ PlayerLoad™ and its individual planes were measured continuously using micromechanical-electrical systems (MEMS) positioned at the scapulae (SCAP) and near the centre of mass (COM). PlayerLoad™ and its individual planars showed moderate and high test-retest reliability at both locations (ICC: 0.80-0.99). No between-half differences in PLvM were observed; however, within-half increases were recorded at the COM, but only during the first half at the SCAP. Greater contributions to PLvM were provided by PLv and PLML when derived from the SCAP and COM, respectively. PLvM (COM: 1451 ± 168; SCAP: 1029 ± 113), PLAr (COM: 503 ± 99; SCAP: 345 ± 61), PLML (COM: 712 ± 124; SCAP: 348 ± 61) and PLv (COM: 797 ± 184; SCAP: 688 ± 124) were significantly greater at the COM compared to the SCAP. Player Load™ and its individual planes are reliable measures during SAFT⁹⁰ and detected within-match changes in movement strategy when the unit was placed at the COM, which may have implications for fatigue management. Inferring alterations in lower-limb movement strategies from MEMS units positioned at the SCAP should be undertaken with caution. Further research is warranted to examine the between-match variability of PlayerLoad™ and its individual planes during actual soccer match play. The principle aim of the third experimental study (Chapter 5) was to examine the within-match patterns of locomotor efficiency in professional soccer, determined as the ratio between tri-axial accelerometer data (PlayerLoad™) and locomotor activities. Secondary aims were to assess the between match variability and determinants of PlayerLoad™ during soccer match play. PlayerLoad™ and its individual planes were recorded during 86 competitive soccer matches in 63 English Championship players (574 match observations). PlayerLoad™, together with the locomotor activity (total distance covered [TDC]) were determined in 15-min segments. Locomotor efficiency was calculated using the ratio of PLvM and TDC (Player Load™ per metre). The proportion of variance explaining the within-match trends in PLvM, PLAr, PLML, PLv, and TDC was determined owing to matches, individual players, and positional role. PLvM, PLAr, PLML, PLv and TDC decreased after the initial 15-min match period (P=0.001; ƞ²=0.22-0.43, large effects). PL: TDC increased in the last 15 minutes of each half (P=0.001; ƞ²= 0.25, large effect). The variance in PLvM during soccer match-play was explained by individual players (63.9%; P=0.001) and between-match variation (21.6%; P=0.001), but not positional role (14.1 %; P= 0.36). Locomotor efficiency is lower during the latter stages of each half of competitive soccer match-play, a trend synonymous with observations of increased injury incidence and fatigue in these periods. Locomotor efficiency may be a valuable metric to identify fatigue and heightened injury risk during soccer training and match-play. In summary, Player Load™ has a moderate to high degree of test-retest reliability and near perfect convergent validity in comparison to HR and V02 at both the SCAP and COM during incremental treadmill running. Moderate to high test-retest reliability was further observed during SAFT⁹⁰ For both treadmill running and SAFT⁹⁰ , PlayerLoad™ was underestimated when worn at the SCAP in comparison to the COM, with different loading contributions observed in the three planes. Caution should be applied in making between-athlete contrasts in loading, and when using recordings from the SCAP to identify lower-limb movement patterns due to this underestimation. However, locomotor efficiency was lower during the latter stages of each half of SAFT⁹⁰ and competitive soccer match-play, a trend synonymous with observations of increased injury incidence and fatigue in these periods. Hence, locomotor efficiency may be a valuable metric to identify fatigue and heightened injury risk during soccer training and match-play.
120

Critical transition phases within top-level female football players in Europe

Day, J. January 2018 (has links)
Women’s football has gained in popularity over the last fifteen years and research into this area has developed. (Lopez, 1997; Scraton, Fasting, Pfister, & Bunuel, 1999; Williams, 2003, 2007, 2011; Fasting, 2004; Brus and Trangbaek, 2004; Pfister, 2006; Cauldwell, 2011). This research study has addressed the historical developments and inequalities with women’s football and extended the existing knowledge of women’s football and developed further the understanding of how female players transition through their playing careers. Study One utilized in-depth interviews, (n=6), with senior administrators in the football organization to examine the organizational structure of six football associations (Denmark, England, Finland, Germany, Norway, The Netherlands), in Europe, to understand where women’s football is situated within the organization. The status and location of women’s football in the football organization was scrutinized to identify whether this affects the allocation of resources and working practices within women’s football. The results identified the challenges women’s football faced in gaining adequate resource to develop the women’s game. Gaps in the development structures were identified and this led to the development of Study Two which recognized the need to examine how the players navigate through these structures. Transition models (Wylleman and Lavallee 2014 holistic career model) have framed Study Two to explain how the players transition through their football careers. Seventeen elite players from the six European countries involved in Study One, were interviewed to gain an in-depth insight into how they navigate through their playing career. The findings from Study Two identified that the players found the transition from junior elite football to senior elite football problematic. This depended upon whether they had sufficient junior pathways in place to aid in this transition. Key themes identified in Study One were interwoven into this study, historical social cultural acceptance, migration and dual careers reaffirmed the complex nature of elite women’s football and challenged the transition literature and models to explain how women’s football fits into these models. Despite these complexities the players navigate through their careers, however there is little known about the player to why they continue playing football with all the challenges they face. Study Three aimed to redress this, a case study narrative approach (Douglass and Carless 2006), has been adopted during this study to elicit the players own life experiences and to identify and evaluate the decision-making processes they go through, to play at the elite level. Two players from Study Two were interviewed five years on from their original interviews to explore how they have continued to navigate through the complex journey of women’s football. The stories gave a more in depth insight into the player’s careers and about the player. Resilience and player identity emerged to why these players continue to play at the elite level. The themes of migration and having to combine an academic/ vocation and elite sporting career successfully continued to develop from Study One and Two.

Page generated in 0.0692 seconds