## Search

Now showing items 1-10 of 18

JavaScript is disabled for your browser. Some features of this site may not work without it.

All of WIRECommunitiesTitleAuthorsIssue DateSubmit DateSubjectsTypesJournalDepartmentPublisherThis CommunityTitleAuthorsIssue DateSubmit DateSubjectsTypesJournalDepartmentPublisher

SubjectsSports Medicine (3)Allometric modelling (2)french-speaking switzerland (2)Knee (2)Log-linear models (2)View MoreJournalJournal of Sports Sciences (2)Annals of Human Biology (1)British Journal of Sports Medicine (1)British Journal of Nutrition (1)Compare: A Journal of Comparative and International Education (1)View MoreAuthorsNevill, Alan M. (9)Koutedakis, Yiannis (3)Adamson-Macedo, Elvidina N. (2)Cockerill, I. M. (2)Holder, Roger L. (2)View MoreYear (Issue Date)1999 (6)1995 (3)1998 (3)1992 (2)1996 (2)TypesArticle (18)

Now showing items 1-10 of 18

- List view
- Grid view
- Sort Options:
- Relevance
- Title Asc
- Title Desc
- Issue Date Asc
- Issue Date Desc
- Results Per Page:
- 5
- 10
- 20
- 40
- 60
- 80
- 100

Body mass index: a measure of fatness or leanness?

Nevill, Alan M.; Holder, Roger L. (Cambridge University Press, 1995)

The relationship between body fat and stature-adjusted weight indices was explored. Assuming the term height’ is a valid indicator of a subject’s lean body mass, heighplweight was shown to be an accurate measure of percentage lean body mass and, as such, a better predictor of percentage body fat than the traditional body mass index (BMI; weight/height’). The name, lean body mass index (LBMI), is proposed for the index height2/weight. These assumptions were confirmed empirically using the results from the Allied Dunbar National Fitness Survey (ADNFS). Using simple allometric modelling, the term heightp explained 74 % of the variance in lean body mass compared with less than 40 YO in body weight. For the majority of ADNFS subjects the fitted exponent from both analyses was approximately p = 2, the only exception being the female subjects aged 55 years and over, where the exponent was found to be significantly less than 2. Using estimates of percentage body fat as the dependent variable, regression analysis was able to confirm that LBMZ was empirically, as well as theoretically, superior to the traditional BMI. Finally, wben the distributional properties of the two indices were compared, BMI was positively skewed and hence deviated considerably from a normal distribution. In contrast, LBMI was found to be both symmetric and normally distributed. When height and weight are recorded in centimetres and kilograms respectively, the suggested working normal range for LBMI is 300-500 with the median at 400.

Modelling the relationship between isokinetic muscle strength and sprint running performance.

Dowson, M. N.; Nevill, Mary E.; Lakomy, H. K.; Nevill, Alan M.; Hazeldine, R. J. (London: Taylor & Francis Ltd., 1998)

Muscle strength is thought to be a major factor in athletic success. However, the relationship between muscle strength and sprint performance has received little attention. The aim of this study was to examine the relationship in elite performers of isokinetic muscle strength across three lower limb joints and sprinting performance, including the use of theoretical models. Eight rugby players, eight track sprinters and eight competitive sportsmen, all elite national or regional competitors, performed sprints over 15 m and 35 m with times recorded over 0-15 m and 30-35 m. Isokinetic torque was measured at the knee, hip and ankle joints at low (1.05 rad s(-1)), intermediate (2.09 or 2.62 rad s(-1)) and high (3.14 or 4.19 rad s(-1)) speeds during concentric and eccentric muscle actions. Using linear regression and expressing sprint performance as time, the strongest relationship, for the joint actions and speeds tested, was between concentric knee extension at 4.19 rad s(-1) and sprint performance (0-15 m times: r=-0.518, P< 0.01; 30-35 m times: r=-0.688, P< 0.01). These relationships were improved for 0-15 m, but not for 30-35 m, by expressing torque relative to body mass (0-15 m times: r=-0.581; 30-35 m times: r=-0.659). When 0-15 m performance was expressed as acceleration rather than time, the correlation was improved slightly (r=0.590). However, when the data (0-15 m times) were fitted to the allometric force model proposed by Gunther, 77% of the variance in concentric knee extension torque at 4.19 rad s(-1) could be explained by 0-15 m times, limb length (knee to buttocks) and body mass. The fitted parameters were similar to those from the theoretical model. These findings suggest that the relationship between isokinetic muscle strength and sprint performance over 0-15 m (during the acceleration phase) is improved by taking limb length and body mass into account.

Scaling, normalizing, and per ratio standards: an allometric modeling approach.

Nevill, Alan M.; Holder, Roger L. (Bethesda, MD: The American Physiological Society, 1995)

The practice of scaling or normalizing physiological variables (Y) by dividing the variable by an appropriate body size variable (X) to produce what is known as a "per ratio standard" (Y/ X), has come under strong criticism from various authors. These authors propose an alternative regression standard based on the linear regression of (Y) on (X) as the predictor variable. However, if linear regression is to be used to adjust such physiological measurements (Y), the residual errors should have a constant variance and, in order to carry out parametric tests of significance, be normally distributed. Unfortunately, since neither of these assumptions appear to be satisfied for many physiological variables, e.g., maximum oxygen uptake, peak and mean power, an alternative approach is proposed of using allometric modeling where the concept of a ratio is an integral part of the model form. These allometric models naturally help to overcome the heteroscedasticity and skewness observed with per ratio variables. Furthermore, if per ratio standards are to be incorporated in regression models to predict other dependent variables, the allometric or log-linear model form is shown to be more appropriate than linear models. By using multiple regression, simply by taking logarithms of the dependent variable and entering the logarithmic transformed per ratio variables as separate independent variables, the resulting estimated log-linear multiple-regression model will automatically provide the most appropriate per ratio standard to reflect the dependent variable, based on the proposed allometric model.

Scaling physiological measurements for individuals of different body size.

Nevill, Alan M.; Ramsbottom, Roger; Williams, Clyde (Springer Verlag, 1992)

This paper examines how selected physiological performance variables, such as maximal oxygen uptake, strength and power, might best be scaled for subject differences in body size. The apparent dilemma between using either ratio standards or a linear adjustment method to scale was investigated by considering how maximal oxygen uptake (l.min-1), peak and mean power output (W) might best be adjusted for differences in body mass (kg). A curvilinear power function model was shown to be theoretically, physiologically and empirically superior to the linear models. Based on the fitted power functions, the best method of scaling maximum oxygen uptake, peak and mean power output, required these variables to be divided by body mass, recorded in the units kg 2/3. Hence, the power function ratio standards (ml.kg-2/3.min-1) and (W.kg-2/3) were best able to describe a wide range of subjects in terms of their physiological capacity, i.e. their ability to utilise oxygen or record power maximally, independent of body size. The simple ratio standards (ml.kg-1.min-1) and (W.kg-1) were found to best describe the same subjects according to their performance capacities or ability to run which are highly dependent on body size. The appropriate model to explain the experimental design effects on such ratio standards was shown to be log-normal rather than normal. Simply by taking logarithms of the power function ratio standard, identical solutions for the design effects are obtained using either ANOVA or, by taking the unscaled physiological variable as the dependent variable and the body size variable as the covariate, ANCOVA methods.

Lifelong Learning and Lifelong Education: a critique

Matheson, David; Matheson, Catherine (Routledge, 1996-01)

It is suddenly fashionable in political circles in the United Kingdom (and elsewhere) to talk about lifelong learning and lifelong education. This seems to be the direct result of the present economic climate which has called into question many previous assumptions: job security has become an effective myth for most of those who can actually get work; long-term unemployment seems to have become structural and permanent. Consequently, the notions of lifelong learning and lifelong education have taken on dimensions far removed from the almost Utopian ideals of their supporters in the years following the publication of the report Learning to Be. Given the current economic gloom, the popularity of the terms with politicians and the fact of being in the European Year of Lifelong Learning, it is perhaps appropriate to take stock of the whole notion of lifelong learning and lifelong education and to see just what meaning (if any) lies behind these words and where they might take us in the future. This essay lays its foundations in the historical background to the ideas of lifelong learning and lifelong education before moving onto a critique of the post-Faure advocates of the principles. It discusses various problems inherent in the concepts (such as lifelong inadequacy) before concluding that, although many of the difficulties in the concepts are due to the confused nature of adult education itself (e.g. is it education or leisure?), there is a greater need than ever for sustained efforts in favour of lifelong education to help to restore the hope which seems to have become a rare commodity among an all too large section of society.

Modelling mood states in athletic performance

Cockerill, I. M.; Nevill, Alan M.; Lyons, Noel (Routledge, 1991)

Because moods are transitory emotional states that can be influenced by a range of personality and environmental factors, the notion that elite athletes will always tend to produce a so-called iceberg profile of mood, and that less successful performers will not, is open to question. Evidence for such a claim is based principally upon descriptive studies. The present experiment used the POMS inventory as a predictor of cross-country running performance among a group of experienced male athletes. Race times from two competitive events were plotted against each of six mood factors. Using data from race 1, a multiple-regression model - incorporating the interdependence of tension, anger and depression - was able to predict rank order of finishing positions for race 2 with acceptable accuracy (rs = 0.74, P <0.01). The present approach differs from the traditional model of mood research in sport in that it provides a prescriptive, rather than a descriptive, focus. Although the model that has been developed appears promising, it is likely that in sports where demands on athletes are very different from those made upon cross-country runners, an alternative model may be required.

Maximal physiological responses to deep and shallow water running.

Dowzer, Clare N.; Reilly, Thomas; Cable, Nigel T.; Nevill, Alan M. (Taylor & Francis, 1999)

The maximal physiological responses to treadmill running (TMR), shallow water running (SWR) and deep water running (DWR) while wearing a buoyancy vest were compared in 15 trained male runners. Measurements included oxygen consumption (VO2 max), respiratory exchange ratio (RER) and heart rate (HR). Treadmill running elicited VO2 max and HRmax, which were higher than the peaks attained in both water tests (p < 0.01). VO2 peak averaged 83.7 and 75.3% of VO2 max for SWR and DWR respectively. Peak HR for SWR and DWR were 94.1 and 87.2% of the HRmax reached in the TMR. RER responses were similar between the three modalities. The observations suggest that the training stimulus provided by water is still adequate for supplementary training. While SWR is potentially an efficient method of maintaining cardiovascular fitness, it needs to be investigated further to establish if it is a viable technique for the injured athlete to employ.

Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine.

Atkinson, Greg; Nevill, Alan M. (Adis International Limited., 1998)

Minimal measurement error (reliability) during the collection of interval- and ratio-type data is critically important to sports medicine research. The main components of measurement error are systematic bias (e.g. general learning or fatigue effects on the tests) and random error due to biological or mechanical variation. Both error components should be meaningfully quantified for the sports physician to relate the described error to judgements regarding 'analytical goals' (the requirements of the measurement tool for effective practical use) rather than the statistical significance of any reliability indicators. Methods based on correlation coefficients and regression provide an indication of 'relative reliability'. Since these methods are highly influenced by the range of measured values, researchers should be cautious in: (i) concluding acceptable relative reliability even if a correlation is above 0.9; (ii) extrapolating the results of a test-retest correlation to a new sample of individuals involved in an experiment; and (iii) comparing test-retest correlations between different reliability studies. Methods used to describe 'absolute reliability' include the standard error of measurements (SEM), coefficient of variation (CV) and limits of agreement (LOA). These statistics are more appropriate for comparing reliability between different measurement tools in different studies. They can be used in multiple retest studies from ANOVA procedures, help predict the magnitude of a 'real' change in individual athletes and be employed to estimate statistical power for a repeated-measures experiment. These methods vary considerably in the way they are calculated and their use also assumes the presence (CV) or absence (SEM) of heteroscedasticity. Most methods of calculating SEM and CV represent approximately 68% of the error that is actually present in the repeated measurements for the 'average' individual in the sample. LOA represent the test-retest differences for 95% of a population. The associated Bland-Altman plot shows the measurement error schematically and helps to identify the presence of heteroscedasticity. If there is evidence of heteroscedasticity or non-normality, one should logarithmically transform the data and quote the bias and random error as ratios. This allows simple comparisons of reliability across different measurement tools. It is recommended that sports clinicians and researchers should cite and interpret a number of statistical methods for assessing reliability. We encourage the inclusion of the LOA method, especially the exploration of heteroscedasticity that is inherent in this analysis. We also stress the importance of relating the results of any reliability statistic to 'analytical goals' in sports medicine.

Heterogeneity of viral IL-6 expression in HHV-8-associated diseases.

Cannon, Jennifer S.; Nicholas, John; Orenstein, Jan M.; Mann, Risa B.; Murray, Paul G.; Browning, Philip J.; DiGiuseppe, Joseph A.; Cesarman, Ethel; Hayward, Gary S.; Ambinder, Richard F. (University of Chicago Press, 1999)

In order to characterize the expression of the viral interleukin-6 (vIL-6) homologue in various human herpesvirus 8 (HHV-8)-associated diseases, in situ hybridization and immunohistochemistry were applied to formalin-fixed specimens. These assays showed consistent expression of vIL-6 in primary effusion lymphomas and in a case of human immunodeficiency virus (HIV)-associated lymphadenopathy with a Castleman's disease-like appearance. In contrast, Kaposi's sarcoma specimens showed marked differences among specimens. In a consecutive series of specimens from the Johns Hopkins archives, vIL-6 expression was demonstrated in one of 13 cases. However, among 7 specimens selected from the AIDS Malignancy Bank because of their high levels of the T1.1 lytic transcript and virion production, vIL-6 expression was consistently demonstrated in infiltrating mononuclear cells and occasional spindle-shaped cells. Thus vIL-6 expression in clinical specimens correlates with other measures of the lytic viral cycle. Both assays generally give congruent results and are consistent with the possibility that vIL-6 expression plays a role in the pathogenesis of a variety of HHV-8-associated diseases.

Detection of secretory immunoglobulin A (SIgA) in saliva of ventilated and non-ventilated preterm neonates.

Hayes, Julie; Adamson-Macedo, Elvidina N.; Perera, Shantha; Anderson, Janet (National Library of Medicine and National Institutes of Health, 1999)

The very young preterm neonate has multiple immune deficiencies which may increase his or her vulnerability to infection. Secretory Immunoglobulin A (SIgA) plays an important role in the protection of epithelial surfaces exposed to the external environment; nevertheless controversy exists with regards to the ontogeny of SIgA in newborns and especially the preterm neonate. The objective was to investigate if SIgA could be detected in the saliva of very/extremely low birthweight neonates (V/ELBW). A total of 707 samples which were collected twice daily (morning and afternoon) for three consecutive days were obtained from sixty-eight preterm neonates (mean gestational age 28 weeks; conceptional age ranged from 25-35 weeks). A repeated measures design was used. Total concentration of SIgA was determined from unstimulated saliva by an Enzyme Linked Immunosorbant Assay technique. Results indicated that SIgA was detectable in the early postnatal period in the saliva of both ventilated preterms who were receiving intravenous total parenteral nutrition (TPN) and non-ventilated preterms. A 3-way repeated measures Analysis of Variance (ANOVA) showed no significant effect from 'before' and 'after' samples during a period of spontaneous activity, time and day of sampling. A significant effect of mode of nutrition was found; neonates who were receiving expressed breast milk had significantly higher concentrations of SIgA than those infants receiving TPN (df=3, F=14.27, p<0.0001). These results have implications for the care of the preterm neonate in intensive care.

The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.