216 research outputs found

    BIOMECHANICAL PROFILE OF SOCCER GOALKEEPERS

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    Although the soccer goalkeeper often plays a decisive role in the outcome of a match, research on the goalkeeper’s actions or the qualities required of a top class goalkeeper is scarce. With this study we attempted to define a biomechanical profile of the goalkeeper. We tested whether the skill level of 6 goalkeepers, determined by the league they played in, correlated with a number of biomechanical tests. The tests were devised as standardized measurements of typical goalkeeper actions; they comprised various jumps, a short sprint and a leg strength measurement. We found no correlation between the goalkeepers’ skill level and their score in any of the tests. Thus, with reservation for the limited number of subjects, we conclude that the measured biomechanical parameters are of minor importance compared to skills as tactical understanding, perception and anticipation

    KINETICS AND ELECTROMYOGRAPHY OF THE MARTIAL ARTS HIGH FRONT KICK

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    INTRODUCTION Fast unloaded movements like striking, throwing and kicking are typically performed in a proximo-distal sequence: Initially proximal segments accelerate while distal segments lag behind, then proximal segments deceler- ate while distal segments accelerate. In kicking, for instance, it is observed that the movement starts with forward angular acceleration of the thigh while the shank lags behind. Then the thigh decelerates while simultaneously the shank accelerates and the foot reaches its maximal velocity. This raises two questions: Is the thigh actively decelerated by the glutei and/or hamstring muscles, or passively decelerated by joint reaction forces from the accelerating shank7 Is acceleration of the shank enhanced by the thigh's deceleration? From a kinematic perspective this movement coordination seems disadvantageous, considering that the resulting linear velocity of the foot relative to the ground equals the vector sum of the resulting linear velocity of the knee relative to the ground and the foot relative to the knee. However, from a kinetic perspective it can be argued that thigh deceleration enhances shah acceleration to a degree where toss of knee velocity is more than accounted for in gain of foot velocity. The theory is that the angularly decelerating thigh exerts a knee joint force which causes angular acceleration of the shank, i.e. a %hip-lash" action. To obtain knowledge regarding how these kinds of movements are performed we decided to examine the martial arts high front kick. Similar to previous kicking studies we did so by kinematic measurements but in addition recorded the electrical activity of selected muscles in order to asses their temporal activation during the kick. METHODS Seventeen skilled taekwondo practitioners (14 males. 3 females) volunteered to take part in this study. Each subject performed three high front kicks aiming at a tennis ball suspended from the ceiling and adjusted to chin level. The fastest kick from each subject was selected for further analysis. The subjects were high speed filmed (200 f.p.s.) from their right side while kicking. Contrasting markers on selected anatomical landmarks enabled subsequent automatic digitisation. Displacement data were lowpass filtered with optimal cut-off frequencies (6-1 0 Hz) determined by use of residual analysis/ Jackson Knee method. Velocities and accelerations were derived from the displacement data by finite difference calculation. During kicking the electtomyographic activity (EMG) from five selected leg muscles were measured with surface electrodes. Kinetic data were obtained through inverse dynamics calculation using a two-segment link-segment model of the kicking leg and the movement equations developed by Putnam (1983). These equations enable division of the resulting moment acting on a segment into muscular components and motion de- pendant components arising from movement of adjacent segments. RESULTS Data for the thigh indicated that deceleration was caused by motion dependant moments arising from shank motion and not by active hip extensor muscles. Shank acceleration was caused partly by a knee extensor muscle moment and partly by a motion dependant moment arising from thigh angular velocity. Both thigh and shank kinetics were supported by EMG recordings. CONCLUSION As part of the accelerating moment acting on the shank was due to thigh angular velocity we suggest that the observed thigh deceleration should be considered unwanted but unavoidable due to shank acceleration. This implies that even though knee extensor muscles are important for shank acceleration the hip flexor muscles must not be neglected

    Evaluating the Quality of Research into a Single Prognostic Biomarker: A Systematic Review and Meta-analysis of 83 Studies of C-Reactive Protein in Stable Coronary Artery Disease

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    Background Systematic evaluations of the quality of research on a single prognostic biomarker are rare. We sought to evaluate the quality of prognostic research evidence for the association of C-reactive protein (CRP) with fatal and nonfatal events among patients with stable coronary disease. Methods and Findings We searched MEDLINE (1966 to 2009) and EMBASE (1980 to 2009) and selected prospective studies of patients with stable coronary disease, reporting a relative risk for the association of CRP with death and nonfatal cardiovascular events. We included 83 studies, reporting 61,684 patients and 6,485 outcome events. No study reported a prespecified statistical analysis protocol; only two studies reported the time elapsed (in months or years) between initial presentation of symptomatic coronary disease and inclusion in the study. Studies reported a median of seven items (of 17) from the REMARK reporting guidelines, with no evidence of change over time. The pooled relative risk for the top versus bottom third of CRP distribution was 1.97 (95% confidence interval [CI] 1.78–2.17), with substantial heterogeneity (I2 = 79.5). Only 13 studies adjusted for conventional risk factors (age, sex, smoking, obesity, diabetes, and low-density lipoprotein [LDL] cholesterol) and these had a relative risk of 1.65 (95% CI 1.39–1.96), I2 = 33.7. Studies reported ten different ways of comparing CRP values, with weaker relative risks for those based on continuous measures. Adjusting for publication bias (for which there was strong evidence, Egger's p<0.001) using a validated method reduced the relative risk to 1.19 (95% CI 1.13–1.25). Only two studies reported a measure of discrimination (c-statistic). In 20 studies the detection rate for subsequent events could be calculated and was 31% for a 10% false positive rate, and the calculated pooled c-statistic was 0.61 (0.57–0.66). Conclusion Multiple types of reporting bias, and publication bias, make the magnitude of any independent association between CRP and prognosis among patients with stable coronary disease sufficiently uncertain that no clinical practice recommendations can be made. Publication of prespecified statistical analytic protocols and prospective registration of studies, among other measures, might help improve the quality of prognostic biomarker research

    One-year efficacy and safety of a fixed combination of insulin degludec and liraglutide in patients with type 2 diabetes: results of a 26-week extension to a 26-week main trial

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    AimsTo confirm, in a 26‐week extension study, the sustained efficacy and safety of a fixed combination of insulin degludec and liraglutide (IDegLira) compared with either insulin degludec or liraglutide alone, in patients with type 2 diabetes.MethodsInsulin‐naïve adults with type 2 diabetes randomized to once‐daily IDegLira, insulin degludec or liraglutide, in addition to metformin ± pioglitazone, continued their allocated treatment in this preplanned 26‐week extension of the DUAL I trial.ResultsA total of 78.8% of patients (1311/1663) continued into the extension phase. The mean glycated haemoglobin (HbA1c) concentration at 52 weeks was reduced from baseline by 1.84% (20.2 mmol/mol) for the IDegLira group, 1.40% (15.3 mmol/mol) for the insulin degludec group and 1.21% (13.2 mmol/mol) for the liraglutide group. Of the patients on IDegLira, 78% achieved an HbA1c of <7% (53 mmol/mol) versus 63% of the patients on insulin degludec and 57% of those on liraglutide. The mean fasting plasma glucose concentration at the end of the trial was similar for IDegLira (5.7 mmol/l) and insulin degludec (6.0 mmol/l), but higher for liraglutide (7.3 mmol/l). At 52 weeks, the daily insulin dose was 37% lower with IDegLira (39 units) than with insulin degludec (62 units). IDegLira was associated with a significantly greater decrease in body weight (estimated treatment difference, −2.80 kg, p < 0.0001) and a 37% lower rate of hypoglycaemia compared with insulin degludec. Overall, all treatments were well tolerated and no new adverse events or tolerability issues were observed for IDegLira.ConclusionsThese 12‐month data, derived from a 26‐week extension of the DUAL I trial, confirm the initial 26‐week main phase results and the sustainability of the benefits of IDegLira compared with its components in glycaemic efficacy, safety and tolerability

    Type II Secretory Phospholipase A2 and Prognosis in Patients with Stable Coronary Heart Disease: Mendelian Randomization Study

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    Serum type II secretory phospholipase A(2) (sPLA(2)-IIa) has been found to be predictive of adverse outcomes in patients with stable coronary heart disease. Compounds targeting sPLA(2)-IIa are already under development. This study investigated if an association of sPLA(2)-IIa with secondary cardiovascular disease (CVD) events may be of causal nature or mainly a matter of confounding by correlated cardiovascular risk markers.Eight-year follow-up data of a prospective cohort study (KAROLA) of patients who underwent in-patient rehabilitation after an acute cardiovascular event were analysed. Associations of polymorphisms (SNP) in the sPLA(2)-IIa-coding gene PLA2G2A with serum sPLA(2)-IIa and secondary fatal or non-fatal CVD events were examined by multiple regression. Hazard ratios (HR) were compared with those expected if the association between sPLA(2)-IIa and CVD were causal. The strongest determinants of sPLA(2)-IIa (rs4744 and rs10732279) were associated with an increase of serum concentrations by 81% and 73% per variant allele. HRs (95% confidence intervals) estimating the associations of the SNPs with secondary CVD events were increased, but not statistically significant (1.16 [0.89-1.51] and 1.18 [0.91-1.52] per variant allele, respectively). However, these estimates were very similar to those expected when assuming causality (1.18 and 1.17), based on an association of natural log-transformed sPLA(2)-IIa concentration with secondary events with HR = 1.33 per unit.The present findings regarding genetic polymorphisms, determination of serum sPLA(2)-IIa, and prognosis in CVD patients are consistent with a genuine causal relationship and thus might point to a valid drug target for prevention of secondary CVD events

    CRP polymorphisms and chronic kidney disease in the third national health and nutrition examination survey

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    <p>Abstract</p> <p>Background</p> <p><it>CRP </it>gene polymorphisms are associated with serum C-reactive protein concentrations and may play a role in chronic kidney disease (CKD) progression. We recently reported an association between the gene variant rs2808630 and CKD progression in African Americans with hypertensive kidney disease. This association has not been studied in other ethnic groups.</p> <p>Methods</p> <p>We used data from 5955 participants from Phase 2 of The Third National Health and Nutrition Examination Survey (1991-1994) to study the association between <it>CRP </it>polymorphisms and CKD prevalence in a population-based sample. The primary outcome was CKD defined as estimated glomerular filtration rate (eGFR) <60 ml/min or the presence of albuminuria. Secondary outcomes were the presence of albuminuria (any degree) and continuous eGFR. Six single nucleotide polymorphisms (SNPs) from the <it>CRP </it>gene, rs2808630, rs1205, rs3093066, rs1417938, rs3093058, and rs1800947, were evaluated.</p> <p>Results</p> <p><it>CRP </it>rs2808630 AG compared to the referent AA genotype was associated with CKD in non-Hispanic blacks (n = 1649, 293 of whom had CKD) with an adjusted odds ratio (OR) of 3.09 (95% CI 1.65-5.8; p = 0.001). For the secondary outcomes, rs2808630 AG compared to the referent AA genotype was associated with albuminuria with an adjusted OR of 3.07 (95% CI 1.59-5.94; p = 0.002), however not with eGFR. There was no association between the SNPs and CKD, albuminuria or eGFR in non-Hispanic whites or Mexicans Americans.</p> <p>Conclusions</p> <p>In this cross-sectional study, the 3' flanking <it>CRP </it>gene variant rs2808630 was associated with CKD, mainly through its association with albuminuria in the non-Hispanic blacks. Despite not finding an association with eGFR, our results support our previous study demonstrating an association between <it>CRP </it>gene variant rs2808630 and CKD progression in a longitudinal cohort of African American with hypertensive kidney disease.</p

    Psoriasis Carries an Increased Risk of Venous Thromboembolism: A Danish Nationwide Cohort Study

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    Psoriasis is an immunoinflammatory disease associated with cardiovascular risk factors, atherothrombotic events, and hypercoagulability. Venous thromboembolism (VTE) is potentially lethal and shares risk factors with psoriasis, but the risk of VTE associated with psoriasis is unknown. The present study investigated the potential association between psoriasis and VTE.Information from nationwide prospectively recorded registers of hospitalization, drug dispensing from pharmacies, socio-economic data, and causes of death was linked on an individual level. In an unselected nationwide cohort, we used multivariate Poisson regression models controlling for age, gender, comorbidity, concomitant medication, socio-economic data, and calendar year, to assess the risk of VTE associated with psoriasis. A total of 35,138 patients with mild and 3,526 patients with severe psoriasis were identified and compared with 4,126,075 controls. Patients with psoriasis had higher incidence rates per 1000 person-years of VTE than controls (1.29, 1.92, and 3.20 for controls, mild psoriasis, and severe psoriasis, respectively). The rate ratio (RR) of VTE was elevated in all patients with psoriasis with RR 1.35 (95% confidence interval [CI] 1.21–1.49) and RR 2.06 (CI 1.63–2.61) for mild and severe psoriasis, respectively. Exclusion of patients with malignancies, and censoring of patients undergoing surgery did not alter the results.This nationwide cohort study indicates that patients with psoriasis are at increased risk of VTE. The risk was highest in young patients with severe psoriasis. Physicians should be aware that patients with psoriasis may be at increased risk of both venous and arterial thromboembolic events

    The first horse herders and the impact of early Bronze Age steppe expansions into Asia

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    This is the author accepted manuscript. The final version is available from AAAS via the DOI in this recordThe file includes the article, supplementary material and additional supplementary materialThe published version of the supplementary materials are at http://science.sciencemag.org/content/suppl/2018/05/08/science.aar7711.DC1Part of the additional supplementary materials for this article are in ORE at http://hdl.handle.net/10871/32792The Yamnaya expansions from the western steppe into Europe and Asia during the Early Bronze Age (~3000 BCE) are believed to have brought with them Indo-European languages and possibly horse husbandry. We analyze 74 ancient whole-genome sequences from across Inner Asia and Anatolia and show that the Botai people associated with the earliest horse husbandry derived from a hunter-gatherer population deeply diverged from the Yamnaya. Our results also suggest distinct migrations bringing West Eurasian ancestry into South Asia before and after but not at the time of Yamnaya culture. We find no evidence of steppe ancestry in Bronze Age Anatolia from when Indo-European languages are attested there. Thus, in contrast to Europe, Early Bronze Age Yamnaya-related migrations had limited direct genetic impact in Asia.The study was supported by the Lundbeck Foundation (EW), the Danish National Research Foundation (EW), and KU2016 (EW). Research at the Sanger Institute was supported by the Wellcome Trust (grant 206194). RM was supported by an EMBO Long-Term Fellowship (ALTF 133-2017). JK was supported by the Human Frontiers Science Program (LT000402/2017). Botai fieldwork was supported by University of Exeter, Archeology Exploration Fund and Niobe Thompson, Clearwater Documentary. AB was supported by NIH grant 5T32GM007197-43. GK was funded by Riksbankens Jubileumsfond and European Research Council. MP was funded by Netherlands Organization for Scientific Research (NWO), project number 276-70-028, IU was funded by the Higher education commission of Pakistan. Archaeological materials from Sholpan and Grigorievka were obtained with partial financial support of the budget program of the Ministry of Education and Science of the Republic of Kazakhstan “Grant financing of scientific research for 2018-2020” No. AP05133498 “Early Bronze Age of the Upper Irtysh”
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