1000 resultados para CRASH TESTS


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Background
A high level of participant skill is influential in determining the outcome of many sports. Thus, tests assessing skill outcomes in sport are commonly used by coaches and researchers to estimate an athlete’s ability level, to evaluate the effectiveness of interventions or for the purpose of talent identification.

Objective

The objective of this systematic review was to examine the methodological quality, measurement properties and feasibility characteristics of sporting skill outcome tests reported in the peer-reviewed literature.

Data Sources
A search of both SPORTDiscus and MEDLINE databases was undertaken.

Study Selection

Studies that examined tests of sporting skill outcomes were reviewed. Only studies that investigated measurement properties of the test (reliability or validity) were included. A total of 22 studies met the inclusion/exclusion criteria.

Study Appraisal and Synthesis Methods
A customised checklist of assessment criteria, based on previous research, was utilised for the purpose of this review.

Results

A range of sports were the subject of the 22 studies included in this review, with considerations relating to methodological quality being generally well addressed by authors. A range of methods and statistical procedures were used by researchers to determine the measurement properties of their skill outcome tests. The majority (95 %) of the reviewed studies investigated test–retest reliability, and where relevant, inter and intra-rater reliability was also determined. Content validity was examined in 68 % of the studies, with most tests investigating multiple skill domains relevant to the sport. Only 18 % of studies assessed all three reviewed forms of validity (content, construct and criterion), with just 14 % investigating the predictive validity of the test. Test responsiveness was reported in only 9 % of studies, whilst feasibility received varying levels of attention.

Limitations

In organised sport, further tests may exist which have not been investigated in this review. This could be due to such tests firstly not being published in the peer-review literature and secondly, not having their measurement properties (i.e., reliability or validity) examined formally.

Conclusions

Of the 22 studies included in this review, items relating to test methodological quality were, on the whole, well addressed. Test–retest reliability was determined in all but one of the reviewed studies, whilst most studies investigated at least two aspects of validity (i.e., content, construct or criterion-related validity). Few studies examined predictive validity or responsiveness. While feasibility was addressed in over half of the studies, practicality and test limitations were rarely addressed. Consideration of study quality, measurement properties and feasibility components assessed in this review can assist future researchers when developing or modifying tests of sporting skill outcomes.

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Objective: To estimate occupational light vehicle (OLV) fatality numbers using vehicle registration and crash data and compare these with previous estimates based on workers' compensation data. Method: New South Wales (NSW) Roads and Traffic Authority (RTA) vehicle registration and crash data were obtained for 2004. NSW is the only Australian jurisdiction with mandatory work-use registration, which was used as a proxy for work-relatedness. OLV fatality rates based on registration data as the denominator were calculated and comparisons made with published 2003/04 fatalities based on workers' compensation data. Results: Thirty-four NSW RTA OLV-user fatalities were identified, a rate of 4.5 deaths per 100,000 organisationally registered OLV, whereas the Australian Safety and Compensation Council (ASCC), reported 28 OLV deaths Australia-wide. Conclusions: More OLV user fatalities were identified from vehicle registration-based data than those based on workers' compensation estimates and the data are likely to provide an improved estimate of fatalities specific to OLV use. Implications: OLV-use is an important cause of traumatic fatalities that would be better identified through the use of vehicle-registration data, which provides a stronger evidence base from which to develop policy responses.

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The aim of this study was to investigate the convergent and predictive validity of two skill tests that examine the ability of golfers to hit accurate approach-iron shots. Twenty-four high-level golfers (handicap = 2.6 ± 1.7) performed the Nine-Ball Skills Test (assesses the ability to shape/control ball trajectory with high accuracy) and the Approach-Iron Skill Test (assesses the ability to hit straight shots from varying distances with high accuracy). Participants then completed at least eight rounds of tournament golf over the following 90 days and reported an indicator of approach-iron accuracy (per cent error index). A moderate correlation (r = 0.50, P < 0.05) was noted between scores for both tests. Generalised estimating equations, using two covariates (lie of the ball and distance to hole), were used to determine model fit and the amount of variance explained for tournament per cent error index. Results showed that the Approach-Iron Skill Test was the slightly stronger predictor of on-course per cent error index. With both test scores considered together, a minimal amount of additional variance was explained. These findings suggest that either of the tests used individually or combined may be used to predict tournament approach iron performance in high-level golfers.

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International visitor arrivals to Bali are examined using univariate and panel Lagrange multiplier (LM) unit root tests with one and two structural breaks to ascertain if shocks to the time path of tourist arrivals are permanent or transitory. The univariate LM unit root tests with one and two structural breaks fail to reject the null hypothesis of a unit root in international visitor arrivals to Bali. However, the panel LM unit root tests with one and two structural breaks applied to a panel of Bali's 11 major source markets reject the null and support the alternative hypothesis of a joint trend-stationary series with transitory shocks. This result suggests that, the effects of the recent terrorist acts on Bali on the growth path of tourist arrivals from major markets are only transitory and that as a consequence Bali's tourism sector is sustainable in the long run.

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Using data on inequality for 21 OECD countries over the period 1870-2011 this paper tests the Piketty hypothesis that income inequality is likely to grow in the 21st century. It is shown that the null hypothesis of trend stationarity of inequality cannot be rejected at conventional significance levels, suggesting that shocks to income inequality are likely to be temporary.

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'Heterogeneous twinning' is defined as plastic deformation due to the formation and progress of twins resulting in surface wrinkles on the deforming part when the initial grain size is relatively large compared to the typical size of the part. In the case of a Twinning Induced Plasticity (TWIP) steel with an initial grain size of ~160. m, the heterogeneous twinning generated visible wrinkles, an orange peel effect, under medium uni-axial strains. The heterogeneous twinning did not occur in the material subjected to high shear strains. The complications resulting from this phenomenon on strain hardening characterization of the TWIP steels using two commonly used mechanical tests, tensile and torsion are discussed along with some experimental aspects of heterogeneous twinning. © 2014.

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In this article three unit root tests that allow for a break in both the seasonal mean and linear trend of the data are proposed. The tests, which can be seen as small-sample corrected versions of already known asymptotic tests, are shown to perform very well in simulations, and much better than their asymptotic counterparts.

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This article proposes new unit root tests for panels where the errors may be not only serial and/or crosscorrelated,but also unconditionally heteroscedastic. Despite their generality, the test statistics are shown tobe very simple to implement, requiring only minimal corrections and still the limiting distributions underthe null hypothesis are completely free from nuisance parameters. Monte Carlo evidence is also providedto suggest that the new tests perform well in small samples, also when compared to some of the existingtests. Supplementary materials for this article are available online.