94 research outputs found

    Track running shoes: a case report of the transition from classical spikes to "super spikes" in track running

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    Research on high-tech running shoes is increasing but few studies are available about the use of high-tech track spike shoes (super spikes), despite their growing popularity among running athletes. The aim of this case study was to investigate kinematics, kinetics, and plantar pressures of an Olympic running athlete using two different types of shoes, to provide an easy and replicable method to assess their influence on running biomechanics. The tested athlete performed six running trials, at the same speed, wearing a pair of normal spikes shoes (NSS) and a super spikes shoe (SSS), in random order. SSS increased contact time, vertical impact, and swing force (Effect Size 3.70, 7.86, and 1.31, respectively), while it reduced foot-strike type and vertical ground reaction force rate (Effect Size 3.62 and 7.21, respectively). Moreover, a significant change was observed in medial and lateral load, with SSS inducing a more symmetrical load distribution between the left and right feet compared to the NSS (SSS left medial load 57.1 +/- 2.1%, left lateral load 42.9 +/- 1.4%, right medial load 55.1 +/- 2.6%, right lateral load 44.9 +/- 2.6%; NSS left medial load 58.4 +/- 2.6%, left lateral load 41.6 +/- 2.1%, right medial load 49.2 +/- 3.7%, right lateral load 50.8 +/- 3.7%). The results of this case study suggest the importance of using individual evaluation methods to assess shoe adaptations in running athletes, which can induce biomechanical modifications and should be considered by coaches to ensure optimal running performance

    Pulmonary function is related to success in junior elite Kumite karatekas

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    Spirometry can be considered a method for measuring lung capacity and speed of air-flow through the airways. Due to its simple application, it is commonly used in sport diagnostics. Aims of this research were to determine the values of ventilation function variables in karatekas competing in kumite discipline and their relationship to result. The sample included 51 junior karate athletes (with defined subgroups of more successful [n=31] and less successful [n=20]), competing in kumite discipline, from nine European countries. Their values of some ventilation function variables were measured. Measurement procedures were chosen and used according to acknowledged literature. By univariate analysis of differences, significant differences between more successful and less successful competitors were determined in the following variables: forced vital capacity (more successful 5.24\ub10.56 l; less successful 4.27\ub10.61 l; p=0.00), forced expiratory volume in 1 second (more successful 4.13\ub10.68 l; less successful 3.69\ub10.57 l; p=0.02), ratio of forced expiratory volume in 1 second/forced vital capacity (more successful 78.98\ub110.29%; less successful 86.64\ub18.37%; p=0.01) and maximal voluntary ventilation (more successful 150.46\ub131.14 l/min; less successful 125.50\ub129.49 l/min; p=0.01). More successful contestants showed higher values in some relevant variables compared to less successful ones supporting a relationship to result

    Intra-positional and inter-positional differences in somatotype components and proportions of particular somatotype categories in youth volleyball players

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    Objective(s). Main aim of this cross-sectional study was to analyse intra-positional, inter-positional differences in proportions of particular somatotype categories in youth volleyball players. Methods. Heath-Carter method was used to determine somatotype characteristics of 181 young female volleyball players (age 14.05\ub10.93, height 170.03\ub17.61 cm, mass 57.80\ub18.59 kg, body mass index 19.99\ub12.37 kg/m2, somatotype 4.33-2.79-3.73\ub11.02-1.02-1.25). Dependent variables were playing position, player efficacy. Only 7 somatotype categories (of possible 13) were obtained. Results. By analysing intra-positional differences, a significantly higher frequency of somatotype categories dominated by the ectomorph component was established in a subsample of more successful players, and a significantly higher frequency of somatotype categories dominated by the endomorph component was found in a subsample of less efficient players. The most frequent somatotype category in all player positions in a sample of more efficient volleyball players is the balanced ectomorph. The smallest number of somatotype categories (only three) was obtained in the subsample of more efficient middle hitters. It indirectly indicates that the most stringent requirements for selection according to the body build are for that position. Similar small inter-positional differences were obtained in both subsamples. Ectomorph somatotype component was most pronounced in young middle-hitters, and endomorph in liberos. Small inter-positional differences in both subsamples are probably consequences of previous selection processes within the clubs. Conclusion. Results obtained in this study provide a clearer insight into inter-positional, intra-positional differences in somatotype categories of young female volleyball players

    Control of hyperglycaemia in paediatric intensive care (CHiP): study protocol.

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    BACKGROUND: There is increasing evidence that tight blood glucose (BG) control improves outcomes in critically ill adults. Children show similar hyperglycaemic responses to surgery or critical illness. However it is not known whether tight control will benefit children given maturational differences and different disease spectrum. METHODS/DESIGN: The study is an randomised open trial with two parallel groups to assess whether, for children undergoing intensive care in the UK aged <or= 16 years who are ventilated, have an arterial line in-situ and are receiving vasoactive support following injury, major surgery or in association with critical illness in whom it is anticipated such treatment will be required to continue for at least 12 hours, tight control will increase the numbers of days alive and free of mechanical ventilation at 30 days, and lead to improvement in a range of complications associated with intensive care treatment and be cost effective. Children in the tight control group will receive insulin by intravenous infusion titrated to maintain BG between 4 and 7.0 mmol/l. Children in the control group will be treated according to a standard current approach to BG management. Children will be followed up to determine vital status and healthcare resources usage between discharge and 12 months post-randomisation. Information regarding overall health status, global neurological outcome, attention and behavioural status will be sought from a subgroup with traumatic brain injury (TBI). A difference of 2 days in the number of ventilator-free days within the first 30 days post-randomisation is considered clinically important. Conservatively assuming a standard deviation of a week across both trial arms, a type I error of 1% (2-sided test), and allowing for non-compliance, a total sample size of 1000 patients would have 90% power to detect this difference. To detect effect differences between cardiac and non-cardiac patients, a target sample size of 1500 is required. An economic evaluation will assess whether the costs of achieving tight BG control are justified by subsequent reductions in hospitalisation costs. DISCUSSION: The relevance of tight glycaemic control in this population needs to be assessed formally before being accepted into standard practice

    Plasma Chemokine Levels Are Associated with the Presence and Extent of Angiographic Coronary Collaterals in Chronic Ischemic Heart Disease

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    In patients with chronic ischemic heart disease (IHD), the presence and extent of spontaneously visible coronary collaterals are powerful determinants of clinical outcome. There is marked heterogeneity in the recruitment of coronary collaterals amongst patients with similar degrees of coronary artery stenoses, but the biological basis of this heterogeneity is not known. Chemokines are potent mediators of vascular remodeling in diverse biological settings. Their role in coronary collateralization has not been investigated. We sought to determine whether plasma levels of angiogenic and angiostatic chemokines are associated with of the presence and extent of coronary collaterals in patients with chronic IHD.We measured plasma concentrations of angiogenic and angiostatic chemokine ligands in 156 consecutive subjects undergoing coronary angiography with at least one ≥90% coronary stenosis and determined the presence and extent of spontaneously visible coronary collaterals using the Rentrop scoring system. Eighty-eight subjects (56%) had evidence of coronary collaterals. In a multivariable regression model, the concentration of the angiogenic ligands CXCL5, CXCL8 and CXCL12, hyperlipidemia, and an occluded artery were associated with the presence of collaterals; conversely, the concentration of the angiostatic ligand CXCL11, interferon-γ, hypertension and diabetes were associated with the absence of collaterals (ROC area 0.91). When analyzed according to extent of collateralization, higher Rentrop scores were significantly associated with increased concentration of the angiogenic ligand CXCL1 (p<0.0001), and decreased concentrations of angiostatic ligands CXCL9 (p<0.0001), CXCL10 (p = 0.002), and CXCL11 (p = 0.0002), and interferon-γ (p = 0.0004).Plasma chemokine concentrations are associated with the presence and extent of spontaneously visible coronary artery collaterals and may be mechanistically involved in their recruitment

    Is There an Economical Running Technique? A Review of Modifiable Biomechanical Factors Affecting Running Economy

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