827 research outputs found

    LANDING PATTERN AND VERTICAL LOADING RATES DURING SHOD AND BAREFOOT RUNNING IN HABITUAL SHOD RUNNERS

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    There is evidence to support that habitual barefoot runners are able to disperse impact loading rates by landing pattern modification. However, case studies have been reported that barefoot running may cause stress fractures. It may be due to the immediate biomechanical response difference between habitual and novice barefoot runners. Therefore, purpose of this study was to examine the immediate effects of barefoot running in habitual shod runners. Thirty habitual shod runners were asked to run on an instrumented treadmill at 10km/hr in shod and barefoot. Vertical average (VALR) and instantaneous loading rates (VILR) were obtained by previously established methods. The landing pattern was presented as a ratio between number of footfall with heel-strike and the total step number. Twenty out of 30 participants demonstrated an automatic transition to a non-heel-strike landing. A mixed landing pattern was observed in 10 participants. Compared to shod running, both VALR and VILR significantly reduced during barefoot running (

    Editorial: COVID-19 pandemic:A curve ball for athletes

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    More than 30 months since the discovery of the novel respiratory coronavirus in 2019, COVID-19 related public health orders and restrictions remain active in many countries on the globe in late 2022. These measures, such as city lockdown, border closure, travel restrictions, social distancing practice, and mandatory use of facemasks, affect all segments of the population. During the pandemic, we have witnessed the most significant disruption to the worldwide sports calendar since the World War II. From a global perspective, many international sports events, such as The Olympic Games Tokyo 2020, SummerWorld University Games, and theWorld Games have been postponed; and more than 150 international sports events involving both professional and recreational sportsmen have been canceled. In this series, we cover original articles examining the effect of COVID-19 on the training routine and performance in five types of athletes, including distance runners (Chan et al.), soccer/football players (Wagemans et al.; Keemss et al.), bodybuilders (Imboden et al.; Iff et al.), volleyball players (Morath et al.), and paralympic athletes (Busch et al.). We are aware that this field of research is highly dynamic with new data available almost on a daily base. Hence, we aim to bemore inclusive in this Research Topic and involve a wider scope of research questions and different methodological approaches, which allow us a better coverage of this emerging and evolving Research Topic. These findings provide important information for athletes, coaches, physical trainers, and healthcare team members to identify potential health issues that may be related to the pandemic, plan specifically how we can minimize the negative influence, as well as design contingency training plan for postponed tournaments. Although COVID-19 attacks our respiratory system and potentially causes a decline in physical condition, we observed adverse findings from the studies in this Research Topic in terms of physical training. Iff et al. and Keemss et al. reported a pandemic related negative impact on the physical performance in body builders and youth soccer players, respectively. In contrast, Chan et al. and Wagemans et al. did not find any substantial differences in terms of physical function or training intensity in professional soccer players and recreational distance runners. Interestingly, it seems that COVID-19 and its related public health restrictions result in a greater influence on people’s mental than physical health. For example, Imboden et al., Busch et al., and Iff et al. reported that athletes exhibited poorer mood during the pandemic and this psychological impact may indeed lead to a change in living habits, such as increase alcoholic and cannabis intake. From a global perspective, this Research Topic also includes an investigation of COVID transmission within volleyball games. Morath et al. conducted contact tracing in a professional volleyball teamin Germany. They found that players who strictly adhere to the recommended hygiene guidelines and regulations during both training and matches are of lower risk contracting the virus, but coaches and players are advised to avoid nonessential interpersonal contacts outside the training hours to prevent the spread of infection. Although the guest editors would love to see more views, downloads, and citations of papers included in this series, we sincerely hope that athletes, coaches, and concerning healthcare professionals do not require the information presented in this Research Topic due to another wave of pandemic and disruption. May COVID-19 will be soon behind us and becomes a historical terminology in near future

    A validation study of a smartphone application for functional mobility assessment of the elderly

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    AbstractBackgroundTo minimize the reaction time and position judgment error using stopwatch-timed measures, we developed a smartphone application to measure performance in the five-time sit-to-stand (FTSTS) and timed up-and-go (TUG) tests.ObjectiveThis study aimed to validate this smartphone application by comparing its measurement with a laboratory-based reference condition.MethodsThirty-two healthy elderly people were asked to perform the FTSTS and TUG tests in a randomized sequence. During the tests, their performance was concurrently measured by the smartphone application and a force sensor installed in the backrest of a chair. The intraclass correlation coefficient [ICC(2,1)] and Bland–Altman analysis were used to calculate the measurement consistency and agreement, respectively, between these two methods.ResultsThe smartphone application demonstrated excellent measurement consistency with the lab-based reference condition for the FTSTS test [ICC(2,1) = 0.988] and TUG test [ICC(2,1) = 0.946]. We observed a positive bias of 0.27 seconds (95% limits of agreement, −1.22 to 1.76 seconds) for the FTSTS test and 0.48 seconds (95% limits of agreement, −1.66 to 2.63 seconds) for the TUG test.ConclusionWe cross-validated the newly developed smartphone application with the laboratory-based reference condition during the examination of FTSTS and TUG test performance in healthy elderly

    Trajectory of functional outcome and health status after moderate-to-major trauma in Hong Kong: A prospective 5 year cohort study

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    Background Trauma care systems in Asia have been developing in recent years, but there has been little long-term outcome data from injured survivors. This study aims to evaluate the trajectory of functional outcome and health status up to five years after moderate to major trauma in Hong Kong. Methods We report the five year follow up results of a multicentre, prospective cohort from the trauma registries of three regional trauma centres in Hong Kong. The original cohort recruited 400 adult trauma patients with ISS ≥ 9. Telephone follow up was conducted longitudinally at seven time points, and the extended Glasgow Outcome Scale (GOSE) and Short-Form 36 (SF36) were tracked. Results 119 out of 309 surviving patients (39%) completed follow up after 5 years. The trajectory of GOSE, PCS and MCS showed gradual improvements over the seven time points. 56/119 (47.1%) patients reported a GOSE = 8 (upper good recovery), and the mean PCS and MCS was 47.8 (95% CI 45.8, 49.9) and 55.8 (95% CI 54.1, 57.5) respectively at five years. Univariate logistic regression showed change in PCS - baseline to 1 year and 1 year to 2 years, and change in MCS - baseline to 1 year were associated with GOSE = 8 at 5 years. Linear mixed effects model showed differences in PCS and MCS were greatest between 1-month and 6-month follow up. Conclusions After injury, the most rapid improvement in PCS and MCS occurred in the first six to 12 months, but further recovery was still evident for MCS in patients aged under 65 years for up to five years

    Coupled Hartree-Fock-Bogoliubov kinetic equations for a trapped Bose gas

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    Using the Kadanoff-Baym non-equilibrium Green's function formalism, we derive the self-consistent Hartree-Fock-Bogoliubov (HFB) collisionless kinetic equations and the associated equation of motion for the condensate wavefunction for a trapped Bose-condensed gas. Our work generalizes earlier work by Kane and Kadanoff (KK) for a uniform Bose gas. We include the off-diagonal (anomalous) pair correlations, and thus we have to introduce an off-diagonal distribution function in addition to the normal (diagonal) distribution function. This results in two coupled kinetic equations. If the off-diagonal distribution function can be neglected as a higher-order contribution, we obtain the semi-classical kinetic equation recently used by Zaremba, Griffin and Nikuni (based on the simpler Popov approximation). We discuss the static local equilibrium solution of our coupled HFB kinetic equations within the semi-classical approximation. We also verify that a solution is the rigid in-phase oscillation of the equilibrium condensate and non-condensate density profiles, oscillating with the trap frequency.Comment: 25 page

    Conserving and Gapless Approximations for an Inhomogeneous Bose Gas at Finite Temperatures

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    We derive and discuss the equations of motion for the condensate and its fluctuations for a dilute, weakly interacting Bose gas in an external potential within the self--consistent Hartree--Fock--Bogoliubov (HFB) approximation. Account is taken of the depletion of the condensate and the anomalous Bose correlations, which are important at finite temperatures. We give a critical analysis of the self-consistent HFB approximation in terms of the Hohenberg--Martin classification of approximations (conserving vs gapless) and point out that the Popov approximation to the full HFB gives a gapless single-particle spectrum at all temperatures. The Beliaev second-order approximation is discussed as the spectrum generated by functional differentiation of the HFB single--particle Green's function. We emphasize that the problem of determining the excitation spectrum of a Bose-condensed gas (homogeneous or inhomogeneous) is difficult because of the need to satisfy several different constraints.Comment: plain tex, 19 page

    Pentaquark as Kaon-Nucleon Resonance

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    Several recent experiments have reported evidence for a narrow feature in the K(+)-neutron system, an apparent resonant state ~ 100 MeV above threshold and with a width < 25 MeV. This state has been labelled as Theta(+) (previously as Z(*)), and because of the implied inclusion of a anti-strange quark, is referred to as a pentaquark, that is, five quarks within a single bag. We present an alternative explanation for such a structure, as a higher angular momentum resonance in the isospin zero K(+) -N system. One might call this an exit channel or a molecular resonance. In a non-relativistic potential model we find a possible candidate for the kaon-nucleon system with relative angular momentum L=3, while L=1 and 2 states possess centrifugal barriers too low to confine the kaon and nucleon in a narrow state at an energy so high above threshold. A rather strong state-dependence in the potential is essential, however, for eliminating an observable L=2 resonance at lower energies.Comment: 4 page

    Recreational specialization and the marine-based conservation behaviour intention of recreational divers in Hong Kong

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    This study examined divers' recreational specialization, pro-environmental attitudes, and marine-based conservation behaviour intentions. A questionnaire-based data collection approach was used to survey 398 divers who visited popular diving sites in Hong Kong by employing structural equation modelling to determine the potential relationships among the proposed variables. The results showed a statistically positive relationship between divers' recreational specialization and their pro-environmental attitudes, along with a statistically valid relationship between divers' recreational specialization and their marine-based conservation behaviour intentions. However, divers' pro-environmental attitudes were not statistically significant with their marine-based conservation behaviour intentions; thus, the discrepancy regarding different research findings between the current and previous studies was further discussed. In particular, our findings confirmed that recreational specialization could be a reliable predictor of divers' pro-environmental attitudes and marine-based conservation behaviour intentions to fill the research gaps regarding scuba diving-based nature tourism in Hong Kong. Consequently, management implications and recommendations were presented in accordance with the development of marine environmental conservation and sustainable scuba diving tourism in Hong Kong

    Visiting urban green space as a climate-change adaptation strategy: Exploring push factors in a push–pull framework

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    Urban green space (UGS) offers users multiple ecosystem services and amenities. This study investigated whether residents used UGS visitation in summer as a sustainable measure to tackle hot weather and associated climate-change impacts in humid-subtropical Hong Kong. Attributes of the indoor residential environment, seldom examined in park-visitation studies, were evaluated as push factors to visit UGS through a push–pull theoretical framework. A questionnaire survey of 483 respondents targeted urban park users. The results indicated that UGS visit frequency and stay duration were relatively low in hot summer. Ordinal multiple regression showed that indoor living conditions, residence location, living routine, and habit and personal health impacts were significantly correlated with UGS visits. Interdependence between push and pull factors was detected, demonstrating that intrinsic UGS environmental conditions could constrain UGS visits despite the motivations of push factors. The results indicated the need to improve the microclimate-regulating function in UGS. It could be achieved mainly by optimizing the nature-based design to promote UGS as an adaptive measure to combat the thermal stress brought by climate change. The findings yielded hints to shape visiting habits and suggestions to improve UGS management
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