Body composition of English Premier League soccer players: Influence of playing position,international status,and ethnicity     

Laura Sutton  Mark Scott  Joanne Wallace  Tom Reilly 《Journal of sports sciences》2013,31(10):1019-1026

Abstract

Body composition is a key consideration in the physical make-up of professional soccer players. The aims of the present study were to determine whether the body composition of professional soccer players varied according to playing position, international status or ethnicity, and to establish which variables best distinguished the soccer players from a reference group. Body composition was assessed using dual-energy X-ray absorptiometry in 64 male professional soccer players. Measured variables included bone mineral density and the relative amounts of lean and fat mass. Data were analysed using analysis of variance and stepwise discriminant function. The soccer players recorded better values than a reference group (n = 24) for all body composition compartments. Percent lean mass and bone mineral density were the variables best able to identify the soccer players (95.5% correctly classified). Differences in body composition were evident between goalkeepers and outfield players, but not between outfield playing positions. No differences were found on the basis of international status. The non-Caucasian players demonstrated significantly lower percent body fat (9.2 ± 2.0%) than the Caucasian players (10.7 ± 1.8%). It was concluded that body composition is important for elite soccer players, but that homogeneity between players at top professional clubs results in little variation between individuals.  相似文献   

Randomized controlled trial of effectiveness of pedometers on general practitioners' attitudes to engagement in and promotion of physical activity     

Ina James  Andy Smith  Teena Smith  Edward Kirby  Philippa Press  Patrick Doherty 《Journal of sports sciences》2013,31(7):753-758

Abstract

Pedometers have been identified as a tool for health professionals to promote physical activity. This study, which aimed to evaluate the effectiveness of wearing a pedometer on general practitioners' attitudes to promoting physical activity, was a pragmatic, multi-centred, randomized controlled trial within a primary care trust in England. The participants were 102 general practitioners (GPs). Eighty-five (48 males, 37 females) of the GPs completed pre and post questionnaires, 43 of whom were in the intervention group. Statistical analysis revealed no significant changes between the control and intervention groups for attitude to engage in physical activity (t ₈₃ = 1.13, CI ?0.362 to 0.099) or attitude to promote physical activity in their patients (t ₈₃ = 1.7, CI ?0.593 to 0.045). A higher volume of walking was significantly correlated with a more positive attitude to engage in physical activity (r = 0.58, P < 0.01) but not with a more positive attitude to promoting physical activity. Wearing a pedometer had no significant effect on GPs' attitudes to engaging in physical activity or promoting physical activity in their patients.  相似文献   

The validity and reliability of a novel indoor player tracking system for use within wheelchair court sports     

James Rhodes  Barry Mason  Bertrand Perrat  Martin Smith 《Journal of sports sciences》2013,31(17):1639-1647

Abstract

The aim of the current study was to investigate the validity and reliability of a radio frequency-based system for accurately tracking athlete movement within wheelchair court sports. Four wheelchair-specific tests were devised to assess the system during (i) static measurements; (ii) incremental fixed speeds; (iii) peak speeds; and (iv) multidirectional movements. During each test, three sampling frequencies (4, 8 and 16 Hz) were compared to a criterion method for distance, mean and peak speeds. Absolute static error remained between 0.19 and 0.32 m across the session. Distance values (test (ii)) showed greatest relative error in 4 Hz tags (1.3%), with significantly lower errors seen in higher frequency tags (<1.0%). Relative peak speed errors of <2.0% (test (iii)) were revealed across all sampling frequencies in relation to the criterion (4.00 ± 0.09 m · sˉ¹). Results showed 8 and 16 Hz sampling frequencies displayed the closest-to-criterion values, whilst intra-tag reliability never exceeded 2.0% coefficient of variation (% CV) during peak speed detection. Minimal relative distance errors (<0.2%) were also seen across sampling frequencies (test (iv)). To conclude, the indoor tracking system is deemed an acceptable tool for tracking wheelchair court match play using a tag frequency of 8 or 16 Hz.  相似文献   

Do habitual foot-strike patterns in running influence functional Achilles tendon properties during gait?     

Scott C. Wearing  I. S. Davis  T. Brauner  S. L. Hooper  T. Horstmann 《Journal of sports sciences》2013,31(23):2735-2743

ABSTRACT

The capacity of foot-strike running patterns to influence the functional properties of the Achilles tendon is controversial. This study used transmission-mode ultrasound to investigate the influence of habitual running foot-strike pattern on Achilles tendon properties during barefoot walking and running. Fifteen runners with rearfoot (RFS) and 10 with a forefoot (FFS) foot-strike running pattern had ultrasound transmission velocity measured in the right Achilles tendon during barefoot walking (≈1.1 ms^?1) and running (≈2.0 ms^?1). Temporospatial gait parameters, ankle kinematics and vertical ground reaction force were simultaneously recorded. Statistical comparisons between foot-strike patterns were made using repeated measure ANOVAs. FFS was characterised by a significantly shorter stance duration (?4%), greater ankle dorsiflexion (+2°), and higher peak vertical ground reaction force (+20% bodyweight) than RFS running (P < .05). Both groups adopted a RFS pattern during walking, with only the relative timing of peak dorsiflexion (3%), ground reaction force (1–2%) and peak vertical force loading rates (22–23%) differing between groups (P < .05). Peak ultrasound transmission velocity in the Achilles tendon was significantly higher in FFS during walking (≈100 ms^?1) and running (≈130 ms^?1) than RFS (P < .05). Functional Achilles tendon properties differ with habitual footfall patterns in recreational runners.  相似文献   

Sex Bias and the Validity of Believed Differences between Male and Female Interscholastic Athletic Coaches     

Cynthia A. Hasbrook  Barbara A. Hart  Sharon A. Mathes  Susan True 《Research quarterly for exercise and sport》2013,84(3):259-267

Abstract

Previous research indicates that young athletes as well as athletic administrators hold gender-role stereotypical beliefs about coaches that disfavor females. The validity of two such beliefs (lack of qualified female coaches and time constraints due to family responsibilities) was examined in a statewide survey of 256 female and 296 male interscholastic coaches and a nationwide survey of 2,719 male and 1,449 female interscholastic coaches. Statistical analyses (p < .001) indicated that female coaches were (a) more qualified than their male counterparts with respect to coaching experience with female teams, professional training, and professional experience; (b) as qualified as male coaches with regard to intercollegiate playing experience; and (c) less qualified than male coaches with respect to high school playing experience and coaching experience with male teams. Findings also indicated that male rather than female coaches more often experienced time constraints due to family responsibilities.  相似文献   

Coping Strategies Used by National Champion Figure Skaters     

Daniel Gould  Laura M. Finch  Susan A. Jackson 《Research quarterly for exercise and sport》2013,84(4):453-468

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A Latent Growth Curve Approach to Investigating Developmental Dynamics and Correlates of Change in Children's Perceptions of Physical Competence     

Terry E. Duncan  Susan C. Duncan 《Research quarterly for exercise and sport》2013,84(4):390-398

Abstract

In both the physical and academic domains interest has recently grown regarding developmental change in children's perceptions of competence. Recent advances in statistical methodology, such as latent growth modeling, enable the researcher to analyze developmental trends from both an inter- and intraindividual perspective, thus serving to increase our understanding of correlates of change in perceived competence. Using latent growth modeling, the purpose of the present study was to investigate developmental change in children's perceived competence at physical skills, examining maturational factors and chronological age as possible correlates of change. Subjects were male adolescents (N = 94). Data were collected during the child's sixth, eighth, and ninth grade school years. Results revealed a good fit for the hypothesized model, which specified mean level changes in the variables over time and an interrelationship among the latent chronometric common factors. Although a significant relationship existed between maturation and perceived competence, no significant relationship was evident between chronological age and perceived competence. Findings are discussed with particular reference to the utility of latent growth curve models for assessing developmental processes at both the inter- and intraindividual level.  相似文献   

Influence of Three Different Training Programs on Strength and Speed of a Limb Movement     

Jim D. Whitley  Leon E. Smith 《Research quarterly for exercise and sport》2013,84(1):132-142

Abstract

The experiment was designed to compare the effects of isometric-isotonic (A), dynamic-overload (B), and free swing (C) exercise programs on the speed and strength of a lateral arm movement The 26 college men in each group—three experimental and one control—were given pre- and post-training speed and strength trials. Each experimental group performed its assigned exercise twice a week during the 10-week training period. Reliability coefficients for both strength and speed of movement measurements were found to be high. Following training there were significant speed increases in both the isometric-isotonic and dynamic-overload groups (t=10.06 and 8.10; however, the difference in speed gain between conditions was nonsignificant (F=.10). Also, strength increases in both of these groups were significant (t=8.81 and 3.08), with that of the isometric-isotonic group significantly greater than the dynamic-overload group (F=5.11). No significant speed or strength gains were registered by either the free swing or control group.  相似文献   

Achievement Examinations in Badminton     

M. Gladys Scott 《Research quarterly for exercise and sport》2013,84(2):242-253

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Age Differences in Children's Ability to Model Motor Behavior     

Jerry R. Thomas  Caryl Pierce  Susan Ridsdale 《Research quarterly for exercise and sport》2013,84(3):592-597

Abstract

In order to investigate the effects of modeling behavior for seven- and nine-year-old children, 30 seven-year-old and 30 nine-year-old females were randomly assigned within age level to three groups. These groups differed according to whether a model was presented at the beginning, midway, or not at all during 12 trials on the stabilometer. Both age groups were found to be similar in performance in the no model condition and, for both age groups, the beginning model condition was found to facilitate performance. However, the introduction of the model after six trials had a detrimental effect on the performance of younger children but facilitated older children's performance. These findings were interpreted in light of a likely increase in the processing capacity of nine year olds as well as an increase in the number of movement schemes that were previously stored in the older girls.  相似文献