1,388 research outputs found

    ANALYSIS OF ELITE GOLFERS’ KINEMATIC SEQUENCE IN FULL-SWING AND PARTIAL SWING SHOTS

    Get PDF
    INTRODUCTION: Proximal-to-distal sequencing (PDS) has been observed in full-swing golf shots as in most throwing and striking skills, where the main goal is to maximize speed in the most distal segment of an open-link system (Zheng et al., 2007). Although PDS primarily is associated with mechanical advantage when the speed requirement is high, this temporal order has also been found and ascribed various merits in relatively slow multi-joint movements (Furuya & Kinoshita, 2007). However, no research to date has examined the sequencing pattern in partial golf shots to submaximal distances. The purpose here was to investigate whether PDS is a common characteristic also in partial swing shots of skilled golf players. METHODS: A total of 47 golfers were investigated, 11 male tournament professionals, 23 male amateurs (HCP 0 ± 2 strokes), and 13 female amateurs (HCP -2 ± 2 strokes) performed partial shots with a wedge to targets at three discrete distances (40, 55 and 70 m), and full-swing shots with a five iron as well as a driver in the same direction for maximal distance. Pelvis, upper torso, and hand movement were recorded in 3D with an electromagnetic tracking system (Polhemus) at 240 Hz. The magnitude of the resultant angular velocity vector of each segment was used to examine the sequencing pattern and the angular speed of segment motions. Movement onset, peak amplitude and time for peak amplitude were analyzed in separate repeated-measure ANOVAs with pre-planned Bonferroni corrected pairwise comparisons. Significance level was set at P < 0.05. RESULTS: This study showed a significant proximal-to-distal temporal relationship of movement onset and maximum angular speed at the pelvis, upper torso and hand segments in the golf swing. The same temporal structure was evident in all test conditions, as well as among different genders and levels of expertise. However, the increment in angular speed from the upper torso to hand were significantly larger for male professionals than for female amateurs at all shot conditions and significantly larger for male amateurs than for female amateurs at full-swing shots. DISCUSSION AND CONCLUSION: While there exists a body of evidence in support for PDS providing mechanical advantages when the highest possible ball speed is to be achieved, merits of PDS in partial golf shots are less evident. However, it has been proposed that a given torque or force can be more accurately generated by a stronger muscle than a weaker muscle (Hamilton et al., 2004) and a potential role of the observed sequencing pattern in partial shots of skilled golf players could be to improve accuracy and minimize the speed-accuracy tradeoff. REFERENCES: Zheng N., Barrentine S.W., Fleizig G.S., Andrews J.R. (2008). Kinematic analysis of swing in pro and amateur golfers, International Journal of Sports Medicine, 6, 487-493. Furuya S., Kinoshita H. (2007). Roles of proximal-to-distal sequential organization of the upper limb segments in striking the keys by expert pianists, Neuroscience Letters, 421, 264-269. Hamilton A., Jones K.E., Wolpert D.M. (2004). The scaling of motor noise with muscle strength and motor unit number in humans, Experimental Brain Research, 157, 417-430

    The self-assessed psychological comorbidities of prurigo in Europe: data from the ESDAP study

    Get PDF
    PS16 Prurigo is defined by the presence of chronic pruritus and multiple localized or generalized pruriginous lesions. The aim of this study was to assess the psychological burden of prurigo in patients of European countries. In this multicentre European study, 3, 635 general dermatology outpatients and 1, 359 controls were included. Socio-demographic data and answers to questionnaires (regarding quality of life, general health, anxiety and depression and suicidal ideation) were collected.There were 27 patients with prurigo; of these, 63% were men, and the mean age was 58.6 years. Among patients with prurigo, 10 of 27 (37%) suffered from anxiety and 8 of 27 (29%) from depression. Suicidal ideation was reported in 5 of 27 (19%) patients, and for 4 of these 5 patients, suicidal ideation was related to their skin disease. These frequencies were higher in the 10 commonest dermatological diseases (including psoriasis, atopic dermatitis and leg ulcers). The impact on quality of life was severe, with a mean Dermatologic Life Quality Index (DLQI) of 12.4, with an extreme impact on quality of life for 23% of patients and a very large impact for 27% of patients.The psychological comorbidities of prurigo are common, greater than those of other skin diseases, and their impact on quality of life is significant. Thus, it is important to study this condition and to find new treatments

    Overview of In Situ X-ray Studies of Light Alloy Solidification in Microgravity

    Get PDF
    Gravity has significant effects on alloy solidification, primarily due to thermosolutal convection and solid phase buoyancy. Since 2004, the European Space Agency has been supporting investigation of these effects by promoting in situ X-ray monitoring of the solidification of aluminium alloys on microgravity platforms, on earth, and in periodically varying g conditions. The first microgravity experiment – investigating foaming of liquid metals – was performed on board a sounding rocket, in 2008. In 2012 the first ever X-ray-monitored solidification of a fully dense metallic alloy in space was achieved: the focus was columnar solidification of an Al-Cu alloy. This was followed in 2015 by a similar experiment, investigating equiaxed solidification. Ground reference experiments were completed in all cases. In addition, experiments have been performed on board parabolic flights – where the effects of varying gravity have been studied. We review here the technical and scientific progress to date, and outline future perspectives

    Dynamical mean-field study of ferromagnetism in the periodic Anderson model

    Full text link
    The ferromagnetic phase diagram of the periodic Anderson model is calculated using dynamical mean-field theory in combination with the modified perturbation theory. Concentrating on the intermediate valence regime, the phase boundaries are established as function of the total electron density, the position of the atomic level and the hybridization strength. The main contribution to the magnetic moment stems from the f-electrons. The conduction band polarization is, depending on the system parameters either parallel or antiparallel to the f-magnetization. By investigating the densities of states, one observes that the change of sign of the conduction band polarization is closely connected to the hybridization gap, which is only apparent in the case of almost complete polarization of the f-electrons. Finite-temperature calculations are also performed, the Curie temperature as function of electron density and f-level position are determined. In the intermediate-valence regime, the phase transitions are found to be of second order.Comment: 12 pages, 11 figures, accepted by Phys. Rev.

    Legumain in acute coronary syndromes: A substudy of the PLATO (Platelet Inhibition and Patient Outcomes) trial

    Get PDF
    Background The cysteine protease legumain is increased in patients with atherosclerosis, but its causal role in atherogenesis and cardiovascular disease is still unclear. The aim of the study was to investigate the association of legumain with clinical outcome in a large cohort of patients with acute coronary syndrome. Methods and Results Serum levels of legumain were analyzed in 4883 patients with acute coronary syndrome from a substudy of the PLATO (Platelet Inhibition and Patient Outcomes) trial. Levels were analyzed at admission and after 1 month follow‐up. Associations between legumain and a composite of cardiovascular death, spontaneous myocardial infarction or stroke, and its individual components were assessed by multivariable Cox regression analyses. At baseline, a 50% increase in legumain level was associated with a hazard ratio (HR) of 1.13 (95% CI, 1.04–1.21), P=0.0018, for the primary composite end point, adjusted for randomized treatment. The association remained significant after adjustment for important clinical and demographic variables (HR, 1.10; 95% CI, 1.02–1.19; P=0.013) but not in the fully adjusted model. Legumain levels at 1 month were not associated with the composite end point but were negatively associated with stroke (HR, 0.62; 95% CI, 0.44–0.88; P=0.0069), including in the fully adjusted model (HR, 0.57; 95% CI, 0.37–0.88; P=0.0114). Conclusions Baseline legumain was associated with the primary outcome in patients with acute coronary syndrome, but not in the fully adjusted model. The association between high levels of legumain at 1 month and decreased occurrence of stroke could be of interest from a mechanistic point of view, illustrating the potential dual role of legumain during atherogenesis and acute coronary syndrome. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT00391872

    Acute, periprocedural and longterm antithrombotic therapy in older adults

    Get PDF
    The first international guidance on antithrombotic therapy in the elderly came from the European Society of Cardiology Working Group on Thrombosis in 2015. This same group has updated its previous report on antiplatelet and anticoagulant drugs for older patients with acute or chronic coronary syndromes, atrial fibrillation, or undergoing surgery or procedures typical of the elderly (transcatheter aortic valve implantation and left atrial appendage closure). The aim is to provide a succinct but comprehensive tool for readers to understand the bases of antithrombotic therapy in older patients, despite the complexities of comorbidities, comedications and uncertain ischaemic- vs. bleeding-risk balance. Fourteen updated consensus statements integrate recent trial data and other evidence, with a focus on high bleeding risk. Guideline recommendations, when present, are highlighted, as well as gaps in evidence. Key consensus points include efforts to improve medical adherence through deprescribing and polypill use; adoption of universal risk definitions for bleeding, myocardial infarction, stroke and cause-specific death; multiple bleeding-avoidance strategies, ranging from gastroprotection with aspirin use to selection of antithrombotic-drug composition, dosing and duration tailored to multiple variables (setting, history, overall risk, age, weight, renal function, comedications, procedures) that need special consideration when managing older adults. © The Author(s) 2022. Published by Oxford University Press on behalf of European Society of Cardiology. All rights reserved.info:eu-repo/semantics/publishedVersio

    Diagnosis of obstructive coronary artery disease using computed tomography angiography in patients with stable chest pain depending on clinical probability and in clinically important subgroups: meta-analysis of individual patient data

    Get PDF
    OBJECTIVE: To determine whether coronary computed tomography angiography (CTA) should be performed in patients with any clinical probability of coronary artery disease (CAD), and whether the diagnostic performance differs between subgroups of patients. DESIGN: Prospectively designed meta-analysis of individual patient data from prospective diagnostic accuracy studies. DATA SOURCES: Medline, Embase, and Web of Science for published studies. Unpublished studies were identified via direct contact with participating investigators. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Prospective diagnostic accuracy studies that compared coronary CTA with coronary angiography as the reference standard, using at least a 50% diameter reduction as a cutoff value for obstructive CAD. All patients needed to have a clinical indication for coronary angiography due to suspected CAD, and both tests had to be performed in all patients. Results had to be provided using 2×2 or 3×2 cross tabulations for the comparison of CTA with coronary angiography. Primary outcomes were the positive and negative predictive values of CTA as a function of clinical pretest probability of obstructive CAD, analysed by a generalised linear mixed model; calculations were performed including and excluding non-diagnostic CTA results. The no-treat/treat threshold model was used to determine the range of appropriate pretest probabilities for CTA. The threshold model was based on obtained post-test probabilities of less than 15% in case of negative CTA and above 50% in case of positive CTA. Sex, angina pectoris type, age, and number of computed tomography detector rows were used as clinical variables to analyse the diagnostic performance in relevant subgroups. RESULTS: Individual patient data from 5332 patients from 65 prospective diagnostic accuracy studies were retrieved. For a pretest probability range of 7-67%, the treat threshold of more than 50% and the no-treat threshold of less than 15% post-test probability were obtained using CTA. At a pretest probability of 7%, the positive predictive value of CTA was 50.9% (95% confidence interval 43.3% to 57.7%) and the negative predictive value of CTA was 97.8% (96.4% to 98.7%); corresponding values at a pretest probability of 67% were 82.7% (78.3% to 86.2%) and 85.0% (80.2% to 88.9%), respectively. The overall sensitivity of CTA was 95.2% (92.6% to 96.9%) and the specificity was 79.2% (74.9% to 82.9%). CTA using more than 64 detector rows was associated with a higher empirical sensitivity than CTA using up to 64 rows (93.4% v 86.5%, P=0.002) and specificity (84.4% v 72.6%, P<0.001). The area under the receiver-operating-characteristic curve for CTA was 0.897 (0.889 to 0.906), and the diagnostic performance of CTA was slightly lower in women than in with men (area under the curve 0.874 (0.858 to 0.890) v 0.907 (0.897 to 0.916), P<0.001). The diagnostic performance of CTA was slightly lower in patients older than 75 (0.864 (0.834 to 0.894), P=0.018 v all other age groups) and was not significantly influenced by angina pectoris type (typical angina 0.895 (0.873 to 0.917), atypical angina 0.898 (0.884 to 0.913), non-anginal chest pain 0.884 (0.870 to 0.899), other chest discomfort 0.915 (0.897 to 0.934)). CONCLUSIONS: In a no-treat/treat threshold model, the diagnosis of obstructive CAD using coronary CTA in patients with stable chest pain was most accurate when the clinical pretest probability was between 7% and 67%. Performance of CTA was not influenced by the angina pectoris type and was slightly higher in men and lower in older patients. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42012002780

    Retracting and seeking movements during laparoscopic goal-oriented movements. Is the shortest path length optimal?

    Get PDF
    Aims- Minimally invasive surgery (MIS) requires a high degree of eye–hand coordination from the surgeon. To facilitate the learning process, objective assessment systems based on analysis of the instruments’ motion are being developed. To investigate the influence of performance on motion characteristics, we examined goaloriented movements in a box trainer. In general, goal-oriented movements consist of a retracting and a seeking phase, and are, however, not performed via the shortest path length. Therefore, we hypothesized that the shortest path is not an optimal concept in MIS. Methods-Participants were divided into three groups (experts, residents, and novices). Each participant performed a number of one-hand positioning tasks in a box trainer. Movements of the instrument were recorded with the TrEndo tracking system. The movement from point A to B was divided into two phases: A-M (retracting) and M-B (seeking). Normalized path lengths (given in %) of the two phases were compared. Results- Thirty eight participants contributed. For the retracting phase, we found no significant difference between experts [median (range) %: 152 (129–178)], residents [164 (126–250)], and novices [168 (136–268)]. In the seeking phase, we find a significant difference (<0.001) between experts [180 (172–247)], residents [201 (163–287)], and novices [290 (244–469)]. Moreover, within each group, a significant difference between retracting and seeking phases was observed. Conclusions- Goal-oriented movements in MIS can be split into two phases: retracting and seeking. Novices are less effective than experts and residents in the seeking phase. Therefore, the seeking phase is characteristic of performance differences. Furthermore, the retracting phase is essential, because it improves safety by avoiding intermediate tissue contact. Therefore, the shortest path length, as presently used during the assessment of basic MIS skills, may be not a proper concept for analyzing optimal movements and, therefore, needs to be revised.Biomechanical EngineeringMechanical, Maritime and Materials Engineerin

    Evaluation of energy and dietary intake estimates from a food frequency questionnaire using independent energy expenditure measurement and weighed food records

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>We have developed a food frequency questionnaire (FFQ) for the assessment of habitual diet, with special focus on the intake of fruit, vegetables and other antioxidant-rich foods and beverages. The aim of the present study was to evaluate the relative validity of the intakes of energy, food and nutrients from the FFQ.</p> <p>Methods</p> <p>Energy intake was evaluated against independent measures of energy expenditure using the ActiReg<sup>® </sup>system (motion detection), whereas 7-days weighed food records were used to study the relative validity of food and nutrient intake. The relationship between methods was investigated using correlation analyses and cross-classification of participants. The visual agreement between the methods was evaluated using Bland-Altman plots.</p> <p>Results</p> <p>We observed that the FFQ underestimated the energy intake by approximately 11% compared to the energy expenditure measured by the ActiReg<sup>®</sup>. The correlation coefficient between energy intake and energy expenditure was 0.54 and 32% of the participants were defined as under-reporters. Compared to the weighed food records the percentages of energy from fat and added sugar from the FFQ were underestimated, whereas the percentage of energy from total carbohydrates and protein were slightly overestimated. The intake of foods rich in antioxidants did not vary significantly between the FFQ and weighed food records, with the exceptions of berries, coffee, tea and vegetables which were overestimated. Spearman's Rank Order Correlations between FFQ and weighed food records were 0.41 for berries, 0.58 for chocolate, 0.78 for coffee, 0.61 for fruit, 0.57 for fruit and berry juices, 0.40 for nuts, 0.74 for tea, 0.38 for vegetables and 0.70 for the intake of wine.</p> <p>Conclusions</p> <p>Our new FFQ provides a good estimate of the average energy intake and it obtains valid data on average intake of most antioxidant-rich foods and beverages. Our study also showed that the FFQs ability to rank participants according to intake of total antioxidants and most of the antioxidant-rich foods was good.</p
    corecore