The assessment of adolescent female athletes using standing and reactive long jumps     

Mark P. Moresi  Elizabeth J. Bradshaw  David Greene  Geraldine Naughton 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):73-84

The aim of this study was to evaluate the reliability of two long jump tasks and their ability to predict 10 m sprint performance in elite adolescent female athletes. Eight junior national-level female track and field athletes completed three standing (SLJ) and reactive long jumps (RLJ) on portable force plates, followed by three 10 m sprints. Intra-class correlation coefficients (ICC) and coefficients of variation (CV) were calculated to examine reliability. Linear regression results identified the best predictor of average and best 10 m sprint time from the jump kinematic and kinetic measures. The ICCs and CVs indicated good reliability for the majority of kinetic measures however, better reliability was reported for the SLJ. The SLJ was a good predictor of best and average 10 m sprint time, with average horizontal power the best predictor of performance (best; R ² = 0.751, p = 0.003, Standard Error of Estimate (SEE)% = 2.2 average; R ² = 0.708, p = 0.005, SEE% = 2.5).  相似文献   

Biomechanical approaches to identify and quantify injury mechanisms and risk factors in women's artistic gymnastics     

Elizabeth J. Bradshaw  Patria A. Hume 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):324-341

Targeted injury prevention strategies, based on biomechanical analyses, have the potential to help reduce the incidence and severity of gymnastics injuries. This review outlines the potential benefits of biomechanics research to contribute to injury prevention strategies for women's artistic gymnastics by identification of mechanisms of injury and quantification of the effects of injury risk factors. One hundred and twenty-three articles were retained for review after searching electronic databases using key words, including ‘gymnastic’, ‘biomech*’, and ‘inj*’, and delimiting by language and relevance to the paper aim. Impact load can be measured biomechanically by the use of instrumented equipment (e.g. beatboard), instrumentation on the gymnast (accelerometers), or by landings on force plates. We need further information on injury mechanisms and risk factors in gymnastics and practical methods of monitoring training loads. We have not yet shown, beyond a theoretical approach, how biomechanical analysis of gymnastics can help reduce injury risk through injury prevention interventions. Given the high magnitude of impact load, both acute and accumulative, coaches should monitor impact loads per training session, taking into consideration training quality and quantity such as the control of rotation and the height from which the landings are executed.  相似文献   

Performance score variation between days at Australian national and Olympic women's artistic gymnastics competition     

Bradshaw EJ  Hume PA  Aisbett B 《Journal of sports sciences》2012,30(2):191-199

We determined the inter-day variability in elite-standard women's artistic gymnastics competition scores. National (50 gymnasts for up to three days) and Olympic (24 gymnasts for up to five days) competition scores published in the public domain ('Giant poster pull-out', 2010 ; Gymnastics Australia, 2008 ) were evaluated using three statistical measures. Analyses of the inter-day differences in the mean scores as a percentage (MDiff%), coefficient of variation percentages for the mean score across both days (CV%), and Pearson correlation coefficients for the inter-day score (r) were interpreted using thresholds from trivial to large. National-class gymnasts' two-day performance variation was trivial for vault, small for floor and beam, and moderate for bars. When senior gymnasts competed for a third day the performance variation increased to moderate for vault. Across five days of Olympic competition there were trivial (e.g. CV%: vault = 0.8) to small (e.g. CV%: bars = 2.0) variations in performances between days on all apparatus. Olympians' performance score consistency is superior to senior, national-class competitors. The performance score consistency required for gymnasts who aspire to participate at the Olympics as a top-24 competitor is better than 3%.  相似文献   

An accurate VO2max nonexercise regression model for 18-65-year-old adults     

Bradshaw DI  George JD  Hyde A  LaMonte MJ  Vehrs PR  Hager RL  Yanowitz FG 《Research quarterly for exercise and sport》2005,76(4):426-432

The purpose of this study was to develop a regression equation to predict maximal oxygen uptake (VO2max) based on nonexercise (N-EX) data. All participants (N = 100), ages 18-65 years, successfully completed a maximal graded exercise test (GXT) to assess VO2max (M = 39.96 mL x kg(-1) x min(-1), SD = 9.54). The N-EX data collected just before the maximal GXT included the participant's age; gender; body mass index (BMI); perceived functional ability (PFA) to walk, jog, or run given distances; and current physical activity (PA-R) level. Multiple linear regression generated the following N-EX prediction equation (R = .93, SEE = 3.45 mL x kg(-1) x min(-1), % SEE = 8.62): VO2max (mL x kg(-1) x min(-1)) = 48.0730 + (6.1779 x gender; women = 0, men = 1) - (0. 2463 x age) - (0.6186 x BMI) + (0.7115 x PFA) + (0.6709 x PA-R). Cross validation using PRESS (predicted residual sum of squares) statistics revealed minimal shrinkage (R(p) = .91 and SEE(p) = 3.63 mL x kg(-1) x min(-1)); thus, this model should yield acceptable accuracy when applied to an independent sample of adults (ages 18-65 years) with a similar cardiorespiratory fitness level. Based on standardized beta-weights, the PFA variable (0.41) was the most effective at predicting VO2max followed by age (-0.34), gender (0.33), BMI (-0.27), and PA-R (0.16). This study provides a N-EX regression model that yields relatively accurate results and is a convenient way to predict VO2max in adult men and women.  相似文献   

The External Change Agent and Curriculum Development: A Metaphor for the Problem of Role     

Marsden Bradshaw 《Cambridge Journal of Education》1978,8(1):57-64

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Handedness and the Development of Direction and Sequencing in Children's Drawings of People     

S. M. Glenn  K. Bradshaw  M. Sharp 《教育心理学》1995,15(1):11-21

The effect of age and handedness on directionality and sequence in drawing was studied in 389 right‐ and left‐handed children aged from 2 to 11 years. Preschool right‐handers were more likely to draw right to left and to produce circles in a clockwise direction. In contrast, preschool left handers drew left to right with anti‐clockwise circle production. By the age of 9 to 11 years right‐handers had switched to predominantly left to right drawing with anti‐clockwise circle production and left‐handers to right to left, drawing and clockwise circle production. Irrespective of handedness, preschool children tended to begin at the bottom of the drawing and work towards the top, whereas the older groups tended to draw from the top to the bottom. It is suggested that these rules of directionality and sequencing may influence how children respond to writing instruction.  相似文献   

Progress Can Really Set You Back     

Amy C. Bradshaw 《TechTrends》2014,58(6):10-11

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