The effect of ball compression and scale court sizes on learning tennis skills of beginner adult tennis players

Numerous studies have demonstrated the positive impact of scaled equipment on the playing performance of young tennis players. Nonetheless, there is a need for further research to explore the impact of scaled equipment on the skill development of beginner adult tennis players. Objective: This study aimed to assess the effects of ball compression and scale court sizes on the learning of tennis skills of beginner adult tennis players. Methods: Twenty-four beginner players (age 20.9 ± 1.2 years) were randomly divided into a regular ball group (RB, n = 12) and a low-compression ball group (LCB, n = 12) on-court training twice per week for six weeks. The RB played with standard yellow tennis balls, while the LCB used low-compression balls (red, orange, and green) during the intervention. Pre and post-tests included the Tennis-Specific Skills Tes (TSST) and the International Tennis Number test (ITN). Results: The results demonstrated that the LCB showed higher technical characteristics after training (p < .05, ηp 2 between .18 and .36) except for the mobility assessment (p > .05, ηp 2 = .02) and the TSST scores in terms of forehand, backhand, and rally length (p < .05, ηp 2 = .16–.19). Conclusions: This study indicates that the LCB might be more suitable equipment to improve technical skills and hitting performances. Practitioners can use the LCB to design an effective training plan, especially for young and adult beginner tennis players.info:eu-repo/semantics/publishedVersio

Effects of a 6-week on-court training program on the International Tennis Number (ITN) and a range of physical fitness characteristics in young tennis players

The study aimed to (i) verify the effects of an on-court training program on the International Tennis Number (ITN) of young tennis players, as well as on a set of change of direction, linear sprint, and maximal oxygen uptake (VO2max) variables, and (ii) identify the main predictors of ITN. The sample consisted of 20 young male tennis players (mean age, 13.62 ± 0.23 years). Players underwent a 6-week on-court training program. The ITN and a number of change of direction variables (T-drill and repeated sprint ability), linear sprint (5 m, 10 m, and 20 m distances), and VO2max were measured. All variables improved significantly between the pre- and posttest (p < 0.001). The ITN (7.98 ± 6.06%, d = 0.82) and VO2max (6.77 ± 1.21%, d = 1.53) showed the greatest relative improvement with moderate to large effect sizes. The hierarchical linear model retained the time (estimate = 18.90, p < 0.001) and the T-drill (estimate = −64.77, p < 0.001) as significant predictors of the ITN. This indicates that the ITN improved significantly over the 6-week training program and that the T-drill test was the best and most significant predictor. Coaches and researchers are encouraged to monitor the ITN along with other physical fitness and technical variables. They can also use the T-drill test to understand the ITN of their playersThis work was supported by national funds (FCT\u2014Portuguese Foundation for Science and Technology) under the project UIDB/DTP/04045/2020info:eu-repo/semantics/publishedVersio

Pretreatment with beta-blockers and the frequency of hypokalemia in patients with acute chest pain

Plasma potassium concentration was measured at admission in 1234 patients who presented with acute chest pain. One hundred and ninety five patients were on P blockers before admission. The potassium concentrations of patients admitted early (within four hours of onsetof symptoms) were compared with those admitted later (4-18 hours after onset of symptoms). There was a transient fall in plasma potassium concentrations in patients not pre-treated with , B blockers. This was not seen in patients who had been on P blockers before admission. Nonselective, B blockers were more effective than cardioselective agents in maintaining concentrationsof plasma potassium. These findings suggest a mechanism for the beneficial effects of ,B blockers on morbidity and mortality in acute myocardial infarction

Work stress and hair cortisol levels among workers in a Bangladeshi ready-made garment factory - results from a cross-sectional study

SummaryEvidence on the association of work stress with cortisol levels is inconsistent and mostly stems from Western countries, with limited generalizability to other regions of the world. These inconsistencies may partly be due to methodological limitations associated with the measurement of cortisol secretion in saliva, serum or urine. The present study set out to explore associations of work stress with long-term integrated cortisol levels in hair among 175 workers of an export oriented ready-made garment (RMG) factory in Dhaka, Bangladesh.Work-related demands (WD), interpersonal resources (IR) and work-related values (WV) were assessed using a psychometrically evaluated interview. WD consisted of four items on physical demands, time pressure, worries about mistakes and exposure to abusive language. IR comprised five items addressing support, recognition, adequate payment, workers’ trust in the management, and the management's trust in workers, as perceived by the workers. WV captured job security, promotion prospects and job latitude by three items. Hair cortisol concentrations (HCC) were analyzed by liquid chromatography–mass spectrometry. Stepwise multivariable linear regression models (backward elimination of predictors) were used to estimate associations of HCC with the three work stress components. For significant work stress component(s), further multivariable linear regression analyses were conducted to explore whether, and if so, which individual item(s) contributed most.The mean HCC equaled 3.27 (SD 2.58) pg/mg. HCC were found to be significantly associated with WV (beta=0.209, p=0.021). Additional analyses of the three WV items revealed that this association was largely driven the item on “promotion prospects” (beta=0.230, p=0.007) implying that the perception of good promotion prospects was associated with higher HCC.The finding of elevated HCC with good promotion prospects may initially seem counter-intuitive, but is supported by research documenting that job promotion may result in poorer mental well-being. Moreover, being promoted in the Bangladeshi RMG industry may represent a stressful experience: job promotions are rare in this setting and are associated with the need to meet exceptional job-related demands. Further research from ethnic and culturally diverse occupational settings is needed to test this hypothesis, to shed light on the reproducibility of our findings and to improve our understanding of the psychobiological implications of psychosocial working conditions across cultures and contexts

Rethinking global cooperation: three new frameworks for collective action in an age of uncertainty

In 2022, the growing impacts of climate change have been felt across the globe, from prolonged drought in the Middle East and North Africa, to erratic monsoons in South Asia and record-breaking heat waves in Europe and China. At the same time, the COVID-19 pandemic—which reached the tragic milestone of one million deaths within the first eight months of this year—and the ongoing war in Ukraine and other violent conflicts have impeded global progress toward the Sustainable Development Goals. To address these and other pressing global challenges, in his 2021 Out Common Agenda report, UN Secretary-General António Guterres called for a Summit of the Future to improve collective action worldwide. Among the summit’s anticipated outcomes are a Declaration on Future Generations, a Global Digital Compact, and a New Agenda for Peace. This report elaborates on the challenges, proposed major elements, and potential spoilers to be overcome by each of these global policy frameworks. It further argues that meaningful civil society engagement in the summit’s preparations can reassure all stakeholders that decisions taken in September 2023 are well-informed, enjoy broad social ownership, and generate a sense of co-responsibility in supporting their implementation.FdR – Publicaties niet-programma gebonde

Road to 2023: our common agenda and the pact for the future

Fears of rising conflict, new COVID-19 variants, irreversible climate change, and eroding collaboration in the global economy threaten to undermine the 2030 Agenda for Sustainable Development and other efforts to advance human progress. Yet, a once-in-a-generation opportunity to review and dramatically improve global tools for managing such enormous challenges, a Summit of the Future, is under serious consideration for September 2023 by the United Nations’ 193 Member States. Informed by research and policy dialogues—initially undertaken for the Albright-Gambari Commission and its follow-through, and most recently to help flesh out key proposals in the Secretary-General’s seminal report, Our Common Agenda—this report’s twenty main recommendations are intended to encourage more ambitious, forward-looking thinking and deliberation on global governance renewal and innovation in the run-up to next year’s Summit.FdR – Publicaties niet-programma gebonde

Theoretical analysis of neutron scattering results for quasi-two dimensional ferromagnets

A theoretical study has been carried out to analyse the available results from the inelastic neutron scattering experiment performed on a quasi-two dimensional spin-1/2 ferromagnetic material $K_2CuF_4$. Our formalism is based on a conventional semi-classical like treatment involving a model of an ideal gas of vortices/anti-vortices corresponding to an anisotropic XY Heisenberg ferromagnet on a square lattice. The results for dynamical structure functions for our model corresponding to spin-1/2, show occurrence of negative values in a large range of energy transfer even encompassing the experimental range, when convoluted with a realistic spectral window function. This result indicates failure of the conventional theoretical framework to be applicable to the experimental situation corresponding to low spin systems. A full quantum formalism seems essential for treating such systems.Comment: 16 pages, 6 figures, 1 Table Submitted for publicatio

Developing a core outcome set for future infertility research : An international consensus development study

STUDY QUESTION: Can a core outcome set to standardize outcome selection, collection and reporting across future infertility research be developed? SUMMARY ANSWER: A minimum data set, known as a core outcome set, has been developed for randomized controlled trials (RCTs) and systematic reviews evaluating potential treatments for infertility. WHAT IS KNOWN ALREADY: Complex issues, including a failure to consider the perspectives of people with fertility problems when selecting outcomes, variations in outcome definitions and the selective reporting of outcomes on the basis of statistical analysis, make the results of infertility research difficult to interpret. STUDY DESIGN, SIZE, DURATION: A three-round Delphi survey (372 participants from 41 countries) and consensus development workshop (30 participants from 27 countries). PARTICIPANTS/MATERIALS, SETTING, METHODS: Healthcare professionals, researchers and people with fertility problems were brought together in an open and transparent process using formal consensus science methods. MAIN RESULTS AND THE ROLE OF CHANCE: The core outcome set consists of: viable intrauterine pregnancy confirmed by ultrasound (accounting for singleton, twin and higher multiple pregnancy); pregnancy loss (accounting for ectopic pregnancy, miscarriage, stillbirth and termination of pregnancy); live birth; gestational age at delivery; birthweight; neonatal mortality; and major congenital anomaly. Time to pregnancy leading to live birth should be reported when applicable. LIMITATIONS, REASONS FOR CAUTION: We used consensus development methods which have inherent limitations, including the representativeness of the participant sample, Delphi survey attrition and an arbitrary consensus threshold. WIDER IMPLICATIONS OF THE FINDINGS: Embedding the core outcome set within RCTs and systematic reviews should ensure the comprehensive selection, collection and reporting of core outcomes. Research funding bodies, the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) statement, and over 80 specialty journals, including the Cochrane Gynaecology and Fertility Group, Fertility and Sterility and Human Reproduction, have committed to implementing this core outcome set. STUDY FUNDING/COMPETING INTEREST(S): This research was funded by the Catalyst Fund, Royal Society of New Zealand, Auckland Medical Research Fund and Maurice and Phyllis Paykel Trust. The funder had no role in the design and conduct of the study, the collection, management, analysis or interpretation of data, or manuscript preparation. B.W.J.M. is supported by a National Health and Medical Research Council Practitioner Fellowship (GNT1082548). S.B. was supported by University of Auckland Foundation Seelye Travelling Fellowship. S.B. reports being the Editor-in-Chief of Human Reproduction Open and an editor of the Cochrane Gynaecology and Fertility group. J.L.H.E. reports being the Editor Emeritus of Human Reproduction. J.M.L.K. reports research sponsorship from Ferring and Theramex. R.S.L. reports consultancy fees from Abbvie, Bayer, Ferring, Fractyl, Insud Pharma and Kindex and research sponsorship from Guerbet and Hass Avocado Board. B.W.J.M. reports consultancy fees from Guerbet, iGenomix, Merck, Merck KGaA and ObsEva. C.N. reports being the Co Editor-in-Chief of Fertility and Sterility and Section Editor of the Journal of Urology, research sponsorship from Ferring, and retains a financial interest in NexHand. A.S. reports consultancy fees from Guerbet. E.H.Y.N. reports research sponsorship from Merck. N.L.V. reports consultancy and conference fees from Ferring, Merck and Merck Sharp and Dohme. The remaining authors declare no competing interests in relation to the work presented. All authors have completed the disclosure form