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This study aimed to investigate the effects of high-definition transcranial direct current stimulation on ankle force sense and underlying cerebral hemodynamics. Sixteen healthy adults (8 males and 8 females) were recruited in the study. Each participant received either real or sham high-definition transcranial direct current stimulation interventions in a randomly assigned order on 2 visits. An isokinetic dynamometer was used to assess the force sense of the dominant ankle; while the functional near-infrared spectroscopy was employed to monitor the hemodynamics of the sensorimotor cortex. Two-way analyses of variance with repeated measures and Pearson correlation analyses were performed. The results showed that the absolute error and root mean square error of ankle force sense dropped more after real stimulation than after sham stimulation (dropped by 23.4% vs. 14.9% for absolute error, and 20.0% vs. 10.2% for root mean square error). The supplementary motor area activation significantly increased after real high-definition transcranial direct current stimulation. The decrease in interhemispheric functional connectivity within the Brodmann's areas 6 was significantly correlated with ankle force sense improvement after real high-definition transcranial direct current stimulation. In conclusion, high-definition transcranial direct current stimulation can be used as a potential intervention for improving ankle force sense. Changes in cerebral hemodynamics could be one of the explanations for the energetic effect of high-definition transcranial direct current stimulation.
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Tobillo , Espectroscopía Infrarroja Corta , Estimulación Transcraneal de Corriente Directa , Adulto , Femenino , Humanos , Masculino , Adulto Joven , Tobillo/fisiología , Circulación Cerebrovascular/fisiología , Hemodinámica/fisiología , Corteza Motora/fisiología , Estimulación Transcraneal de Corriente Directa/métodos , Estudios CruzadosRESUMEN
With the large number of atypical cases in the mpox outbreak, which was classified as a global health emergency by the World Health Organization (WHO) on 23 July 2022, rapid diagnosis of mpox and diseases with similar symptoms to mpox such as chickenpox and respiratory infectious diseases in the early stages of viral infection is key to controlling the spread of the outbreak. In this study, antibodies against the monkeypox virus A29L protein were efficiently and rapidly identified by combining rapid mRNA immunization with high-throughput sequencing of individual B cells. We obtained eight antibodies with a high affinity for A29L validated by ELISA, which were was used as the basis for developing an ultrasensitive fluorescent immunochromatographic assay based on multilayer quantum dot nanobeads (SiTQD-ICA). The SiTQD-ICA biosensor utilizing M53 and M78 antibodies showed high sensitivity and stability of detection: A29L was detected within 20â min, with a minimum detection limit of 5â pg/mL. A specificity test showed that the method was non-cross-reactive with chickenpox or common respiratory pathogens and can be used for early and rapid diagnosis of monkeypox virus infection by antigen detection. This antibody identification method can also be used for rapid acquisition of monoclonal antibodies in early outbreaks of other infectious diseases for various studies.
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Varicela , Enfermedades Transmisibles , Mpox , Humanos , Monkeypox virus/genética , Mpox/diagnóstico , Inmunización , Anticuerpos Monoclonales , Secuenciación de Nucleótidos de Alto Rendimiento , ARN MensajeroRESUMEN
Transcranial direct current stimulation (tDCS) can improve motor control performance under fatigue. However, the influences of tDCS on factors contributing to motor control (e.g., cortical-muscular functional coupling, CMFC) are unclear. This double-blinded and randomized study examined the effects of high-definition tDCS (HD-tDCS) on muscular activities of dorsiflexors and plantarflexors and CMFC when performing ankle dorsi-plantarflexion under fatigue. Twenty-four male adults were randomly assigned to receive five sessions of 20-min HD-tDCS targeting primary motor cortex (M1) or sham stimulation. Three days before and 1 day after the intervention, participants completed ankle dorsi-plantarflexion under fatigue induced by prolonged running exercise. During the task, electroencephalography (EEG) of M1 (e.g., C1, Cz) and surface electromyography (sEMG) of several muscles (e.g., tibialis anterior [TA]) were recorded synchronously. The corticomuscular coherence (CMC), root mean square (RMS) of sEMG, blood lactate, and maximal voluntary isometric contraction (MVC) of ankle dorsiflexors and plantarflexors were obtained. Before stimulation, greater beta- and gamma-band CMC between M1 and TA were significantly associated with greater RMS of TA (r = 0.460-0.619, p = 0.001-0.024). The beta- and gamma-band CMC of C1-TA and Cz-TA, and RMS of TA and MVC torque of dorsiflexors were significantly higher after HD-tDCS than those at pre-intervention in the HD-tDCS group and post-intervention in the control group (p = 0.002-0.046). However, the HD-tDCS-induced changes in CMC and muscle activities were not significantly associated (r = 0.050-0.128, p = 0.693-0.878). HD-tDCS applied over M1 can enhance the muscular activities of ankle dorsiflexion under fatigue and related CMFC.
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Spleen and lymphoid organs are important targets for messenger RNA (mRNA) delivery in various applications. Current nanoparticle delivery methods rely on drainage to lymph nodes from intramuscular or subcutaneous injections. In difficult-to-transfect antigen-presenting cells (APCs), such as dendritic cells (DCs), effective mRNA transfection remains a significant challenge. In this study, a lymphatic targeting carrier using DC membranes is developed, that efficiently migrated to lymphoid organs, such as the spleen and lymph nodes. The nanoparticles contained an ionizable lipid (YK009), which ensured a high encapsulation efficacy of mRNA and assisted mRNA with endosomal escape after cellular uptake. Dendritic cell-mimicking nanoparticles (DCMNPs) showed efficient protein expression in both the spleen and lymph nodes after intramuscular injections. Moreover, in immunized mice, DCMNP vaccination elicited Spike-specific IgG antibodies, neutralizing antibodies, and Th1-biased SARS-CoV-2-specific cellular immunity. This work presents a powerful vaccine formula using DCMNPs, which represents a promising vaccine candidate for further research and development.
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Nanopartículas , Vacunas , Ratones , Animales , Células Dendríticas , ARN Mensajero/metabolismo , Inmunidad Celular , Vacunas/metabolismoRESUMEN
Monkeypox has been declared a public health emergency by the World Health Organization. There is an urgent need for efficient and safe vaccines against the monkeypox virus (MPXV) in response to the rapidly spreading monkeypox epidemic. In the age of COVID-19, mRNA vaccines have been highly successful and emerged as platforms enabling rapid development and large-scale preparation. Here, we develop two MPXV quadrivalent mRNA vaccines, named mRNA-A-LNP and mRNA-B-LNP, based on two intracellular mature virus specific proteins (A29L and M1R) and two extracellular enveloped virus specific proteins (A35R and B6R). By administering mRNA-A-LNP and mRNA-B-LNP intramuscularly twice, mice induce MPXV specific IgG antibodies and potent vaccinia virus (VACV) specific neutralizing antibodies. Further, it elicits efficient MPXV specific Th-1 biased cellular immunity, as well as durable effector memory T and germinal center B cell responses in mice. In addition, two doses of mRNA-A-LNP and mRNA-B-LNP are protective against the VACV challenge in mice. And, the passive transfer of sera from mRNA-A-LNP and mRNA-B-LNP-immunized mice protects nude mice against the VACV challenge. Overall, our results demonstrate that mRNA-A-LNP and mRNA-B-LNP appear to be safe and effective vaccine candidates against monkeypox epidemics, as well as against outbreaks caused by other orthopoxviruses, including the smallpox virus.
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COVID-19 , Mpox , Animales , Ratones , Virus Vaccinia/genética , Monkeypox virus , Mpox/prevención & control , Vacunas Combinadas , Ratones Desnudos , Proteínas Virales/genética , InmunidadRESUMEN
mRNA-based therapy has emerged as the most promising nucleic acid therapy in the fight against COVID-19. However, a safe and efficacious systemic delivery remains a challenge for mRNA therapy. Lipid nanoparticles (LNPs) are currently widely used in mRNA delivery vehicles. Here, a series of ionizable LNPs is rationally designed. YK009-LNP is an optimal delivery platform to carry mRNA. YK009-LNP exhibits higher mRNA delivery efficiency, a more favorable biodistribution pattern, and better safety than the approved MC3-LNP. In addition, mRNA encoding severe acute respiratory syndrome coronavirus 2 Omicron receptor binding domain protein is synthesized and intramuscular administration of mice with YK009-LNP-Omicron mRNA induces a robust immune response and immune protective effect. A novel mRNA delivery vehicle with more powerful delivery efficiency and better safety than the approved LNPs is provided here.
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COVID-19 , Nanopartículas , Animales , Ratones , SARS-CoV-2/genética , Distribución Tisular , Excipientes , Liposomas , ARN Mensajero/genéticaRESUMEN
OBJECTIVE: This study aimed to examine the effects of combining transcranial direct current stimulation (tDCS) and foot core exercise (FCE) on the sensorimotor function of the foot (i.e., toe flexor strength and passive ankle kinesthesia) and static balance. METHODS: In this double-blinded and randomized study, 30 participants were randomly assigned into two groups: tDCS combined with FCE and sham combined with FCE (i.e., control group). The participants received 2 mA stimulation for 20 min concurrently with FCE over 4 weeks (i.e., three sessions per week). After the first two groups completed the intervention, a reference group (FCE-only group) was included to further explore the placebo effects of sham by comparing it with the control group. Foot muscle strength, passive ankle kinesthesia, and static balance were assessed at baseline and after the intervention. RESULTS: Compared with the control group and baseline, tDCS combined with FCE could increase toe flexor strength (p < 0.001) and decrease the passive kinesthesia threshold of ankle eversion (p = 0.002). No significant differences in static balance were observed between tDCS + FCE and control groups. The linear regression models showed an association towards significance between the percent changes in metatarsophalangeal joint flexor strength and the anteroposterior average sway velocity of the center of gravity in one-leg standing with eyes closed following tDCS + FCE (r2 = 0.286; p = 0.057). The exploratory analysis also showed that compared with FCE alone, the sham stimulation did not induce any placebo effects during FCE. CONCLUSION: Participating in 4 weeks of intervention using tDCS in combination with FCE effectively enhances toe flexor strength and foot-ankle sensory function.
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Terapia por Ejercicio , Equilibrio Postural , Estimulación Transcraneal de Corriente Directa , Humanos , Extremidad Inferior , Equilibrio Postural/fisiologíaRESUMEN
BACKGROUND: This study aimed to establish an effective nomogram to predict the survival of heat stroke (HS) based on risk factors. METHODS: This was a retrospective, observational multicenter cohort study. We analyzed patients diagnosed with HS, who were treated between May 1 and September 30, 2018 at 15 tertiary hospitals from 11 cities in Northern China. RESULTS: Among the 175 patients, 32 patients (18.29%) died before hospital discharge. After the univariate analysis, mechanical ventilation, initial mean arterial pressure <70 mmHg, maximum heart rate, lab results on day 1 (white blood cell count, alanine aminotransferase, creatinine), and Glasgow admission prediction score were included in multivariate analysis. Multivariate Cox regression showed that invasive ventilation, initial mean arterial pressure <70 mmHg (1 mmHg=0.133 kPa), and Glasgow admission prediction score were independent risk factors for HS. The nomogram was established for predicting 7-d and 14-d survival in the training cohort. The nomogram exhibited a concordance index (C-index) of 0.880 (95% confidence interval [95% CI] 0.831-0.930) by bootstrapping validation (B=1,000). Furthermore, the nomogram performed better when predicting 14-d survival, compared to 7-d survival. The prognostic index cut-off value was set at 2.085, according to the operating characteristic curve for overall survival prediction. The model showed good calibration ability in the internal and external validation datasets. CONCLUSION: A novel nomogram, integrated with prognostic factors, was proposed; it was highly predictive of the survival in HS patients.
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Anodal transcranial direct current stimulation (a-tDCS) aims to hone motor skills and improve the quality of life. However, the non-repeatability of experimental results and the inconsistency of research conclusions have become a common phenomenon, which may be due to the imprecision of the experimental protocol, great variability of the participant characteristics within the group, and the irregularities of quantitative indicators. The aim of this study systematically summarised and analysed the effect of a-tDCS on lower extremity sensorimotor control under different experimental conditions. This narrative review was performed following the PRISMA guidelines until June 2022 in Web of Science, PubMed, Science Direct, Google Scholar, and Scopus. The findings of the present study demonstrated that a-tDCS can effectively improve the capabilities of lower extremity sensorimotor control, particularly in gait speed and time-on-task. Thus, a-tDCS can be used as an effective ergogenic technology to facilitate physical performance. In-depth and rigorous experimental protocol with larger sample sizes and combining brain imaging technology to explore the mechanism have a profound impact on the development of tDCS.
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The morphological and mechanical properties (e.g., stiffness, stress, and force) of the Achilles tendon (AT) are generally associated with its tendinosis and ruptures, particularly amongst runners. Interest in potential approaches to reduce or prevent the risk of AT injuries has grown exponentially as tendon mechanics have been efficiently improving. The following review aims to discuss the effect of different types of exercise on the AT properties. In this review article, we review literature showing the possibility to influence the mechanical properties of the AT from the perspective of acute exercise and long-term training interventions, and we discuss the reasons for inconsistent results. Finally, we review the role of the habitual state in the AT properties. The findings of the included studies suggest that physical exercise could efficiently improve the AT mechanical properties. In particular, relatively long-term and low-intensity eccentric training may be a useful adjunct to enhance the mechanical loading of the AT.
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BACKGROUND: In view of the global efforts to develop effective treatments for the current worldwide coronavirus 2019 (COVID-19) pandemic, Qingfei Paidu decoction (QPD), a novel traditional Chinese medicine (TCM) prescription, was formulated as an optimized combination of constituents of classic prescriptions used to treat numerous febrile and respiratory-related diseases. This prescription has been used to treat patients with COVID-19 pneumonia in Wuhan, China. Hypothesis/Purpose. We hypothesized that QPD would have beneficial effects on patients with COVID-19. We aimed to prove this hypothesis by evaluating the efficacy of QPD in patients with COVID-19 pneumonia. METHODS: In this single-center, retrospective, observational study, we identified eligible participants who received a laboratory diagnosis of COVID-19 between January 15 and March 15, 2020, in the west campus of Union Hospital in Wuhan, China. QPD was supplied as an oral liquid packaged in 200-mL containers, and patients were orally administered one package twice daily 40 minutes after a meal. The primary outcome was death, which was compared between patients who did and did not receive QPD (QPD and NoQPD groups, respectively). Propensity score matching (PSM) was used to identify cohorts. RESULTS: In total, 239 and 522 participants were enrolled in the QPD and NoQPD groups, respectively. After PSM at a 1 : 1 ratio, 446 patients meeting the criteria were included in the analysis with 223 in each arm. In the QPD and NoQPD groups, 7 (3.2%) and 29 (13.0%) patients died, and those in the QPD group had a significantly lower risk of death (hazard ratio (HR) 0.29, 95% CI: 0.13-0.67) than those in the NoQPD group (p = 0.004). Furthermore, the survival time was significantly longer in the QPD group than in the NoQPD group (p < 0.001). CONCLUSION: The use of QPD may reduce the risk of death in patients with COVID-19 pneumonia.
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Most patients that resuscitate successfully from cardiac arrest (CA) suffer from poor neurological prognosis. DL-3-n-butylphthalide (NBP) is known to have neuroprotective effects via multiple mechanisms. This study aimed to investigate whether NBP can decrease neurological impairment after CA. We studied the protective role of NBP in the hippocampus of a rat model of cardiac arrest induced by asphyxia. Thirty-nine rats were divided randomly into sham, control, and NBP groups. Rats in control and NBP groups underwent cardiopulmonary resuscitation (CPR) 6 min after asphyxia. NBP or vehicle (saline) was administered intravenously 10 min after the return of spontaneous circulation (ROSC). Ultrastructure of hippocampal neurons was observed under transmission electron microscope. NBP treatment improved neurological function up to 72 h after CA. The ultrastructural lesion in mitochondria recovered in the NBP-treated CA model. In conclusion, our study demonstrated multiple therapeutic benefits of NBP after CA.
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Benzofuranos/farmacología , Encefalopatías/prevención & control , Reanimación Cardiopulmonar/efectos adversos , Paro Cardíaco/terapia , Hipocampo/efectos de los fármacos , Neuronas/efectos de los fármacos , Neuroprotección/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Animales , Apoptosis/efectos de los fármacos , Asfixia/complicaciones , Encefalopatías/etiología , Encefalopatías/metabolismo , Encefalopatías/patología , Modelos Animales de Enfermedad , Paro Cardíaco/etiología , Paro Cardíaco/fisiopatología , Hipocampo/metabolismo , Hipocampo/ultraestructura , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , FN-kappa B/metabolismo , Neuronas/metabolismo , Neuronas/ultraestructura , Fosforilación , Ratas Sprague-Dawley , Retorno de la Circulación Espontánea , Transducción de Señal , Factores de Tiempo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Proteínas tau/metabolismoRESUMEN
Purpose: This systematic review aims to examine the efficacy of transcranial direct current stimulation (tDCS) combined with physical training on the excitability of the motor cortex, physical performance, and motor learning. Methods: A systematic search was performed on PubMed, Web of Science, and EBSCO databases for relevant research published from inception to August 2020. Eligible studies included those that used a randomized controlled design and reported the effects of tDCS combined with physical training to improve motor-evoked potential (MEP), dynamic posture stability index (DPSI), reaction time, and error rate on participants without nervous system diseases. The risk of bias was assessed by the Cochrane risk of bias assessment tool. Results: Twenty-four of an initial yield of 768 studies met the eligibility criteria. The risk of bias was considered low. Results showed that anodal tDCS combined with physical training can significantly increase MEP amplitude, decrease DPSI, increase muscle strength, and decrease reaction time and error rate in motor learning tasks. Moreover, the gain effect is significantly greater than sham tDCS combined with physical training. Conclusion: tDCS combined with physical training can effectively improve the excitability of the motor cortex, physical performance, and motor learning. The reported results encourage further research to understand further the synergistic effects of tDCS combined with physical training.
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This study aimed to identify clinical features for prognosing mortality risk using machine-learning methods in patients with coronavirus disease 2019 (COVID-19). A retrospective study of the inpatients with COVID-19 admitted from 15 January to 15 March 2020 in Wuhan is reported. The data of symptoms, comorbidity, demographic, vital sign, CT scans results and laboratory test results on admission were collected. Machine-learning methods (Random Forest and XGboost) were used to rank clinical features for mortality risk. Multivariate logistic regression models were applied to identify clinical features with statistical significance. The predictors of mortality were lactate dehydrogenase (LDH), C-reactive protein (CRP) and age based on 500 bootstrapped samples. A multivariate logistic regression model was formed to predict mortality 292 in-sample patients with area under the receiver operating characteristics (AUROC) of 0.9521, which was better than CURB-65 (AUROC of 0.8501) and the machine-learning-based model (AUROC of 0.4530). An out-sample data set of 13 patients was further tested to show our model (AUROC of 0.6061) was also better than CURB-65 (AUROC of 0.4608) and the machine-learning-based model (AUROC of 0.2292). LDH, CRP and age can be used to identify severe patients with COVID-19 on hospital admission.
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Infecciones por Coronavirus/mortalidad , Infecciones por Coronavirus/terapia , Modelos Logísticos , Aprendizaje Automático , Neumonía Viral/mortalidad , Neumonía Viral/terapia , Adolescente , Adulto , Anciano , COVID-19 , China/epidemiología , Femenino , Hospitalización , Humanos , Masculino , Persona de Mediana Edad , Pandemias , Pronóstico , Curva ROC , Reproducibilidad de los Resultados , Estudios Retrospectivos , Medición de Riesgo/métodos , Adulto JovenRESUMEN
BACKGROUND: Clinical manifestation and neonatal outcomes of pregnant women with coronavirus disease 2019 (COVID-19) were unclear in Wuhan, China. METHODS: We retrospectively analyzed clinical characteristics of pregnant and nonpregnant women with COVID-19 aged from 20 to 40, admitted between January 15 and March 15, 2020 at Union Hospital, Wuhan, and symptoms of pregnant women with COVID-19 and compared the clinical characteristics and symptoms to historic data previously reported for H1N1. RESULTS: Among 64 patients, 34 (53.13%) were pregnant, with higher proportion of exposure history (29.41% vs 6.67%) and more pulmonary infiltration on computed tomography test (50% vs 10%) compared to nonpregnant women. Of pregnant patients, 27 (79.41%) completed pregnancy, 5 (14.71%) had natural delivery, 18 (52.94%) had cesarean section, and 4 (11.76%) had abortion; 5 (14.71%) patients were asymptomatic. All 23 newborns had negative reverse-transcription polymerase chain results, and an average 1-minute Apgar score was 8-9 points. Pregnant and nonpregnant patients show differences in symptoms such as fever, expectoration, and fatigue and on laboratory tests such as neurophils, fibrinogen, D-dimer, and erythrocyte sedimentation rate. Pregnant patients with COVID-19 tend to have more milder symptoms than those with H1N1. CONCLUSIONS: Clinical characteristics of pregnant patients with COVID-19 are less serious than nonpregnant. No evidence indicated that pregnant women may have fetal infection through vertical transmission of COVID-19. Pregnant patients with H1N1 had more serious condition than those with COVID-19.
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OBJECTIVE: To describe the characteristics and outcomes of patients with severe COVID-19 and in-hospital cardiac arrest (IHCA) in Wuhan, China. METHODS: The outcomes of patients with severe COVID-19 pneumonia after IHCA over a 40-day period were retrospectively evaluated. Between January 15 and February 25, 2020, data for all cardiopulmonary resuscitation (CPR) attempts for IHCA that occurred in a tertiary teaching hospital in Wuhan, China were collected according to the Utstein style. The primary outcome was restoration of spontaneous circulation (ROSC), and the secondary outcomes were 30-day survival, and neurological outcome. RESULTS: Data from 136 patients showed 119 (87.5%) patients had a respiratory cause for their cardiac arrest, and 113 (83.1%) were resuscitated in a general ward. The initial rhythm was asystole in 89.7%, pulseless electrical activity (PEA) in 4.4%, and shockable in 5.9%. Most patients with IHCA were monitored (93.4%) and in most resuscitation (89%) was initiated <1â¯min. The average length of hospital stay was 7 days and the time from illness onset to hospital admission was 10 days. The most frequent comorbidity was hypertension (30.2%), and the most frequent symptom was shortness of breath (75%). Of the patients receiving CPR, ROSC was achieved in 18 (13.2%) patients, 4 (2.9%) patients survived for at least 30 days, and one patient achieved a favourable neurological outcome at 30 days. Cardiac arrest location and initial rhythm were associated with better outcomes. CONCLUSION: Survival of patients with severe COVID-19 pneumonia who had an in-hospital cardiac arrest was poor in Wuhan.
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Betacoronavirus , Reanimación Cardiopulmonar/métodos , Infecciones por Coronavirus/complicaciones , Paro Cardíaco/mortalidad , Mortalidad Hospitalaria , Neumonía Viral/terapia , Adulto , Anciano , Anciano de 80 o más Años , COVID-19 , China , Estudios de Cohortes , Femenino , Paro Cardíaco/etiología , Paro Cardíaco/terapia , Humanos , Masculino , Persona de Mediana Edad , Pandemias , Neumonía Viral/complicaciones , Neumonía Viral/etiología , Neumonía Viral/mortalidad , Pronóstico , Estudios Retrospectivos , Medición de Riesgo , SARS-CoV-2 , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
Background and objectives: The popularity of table tennis has increased globally. As a result, the biomechanical movement patterns in the lower limb during table tennis have attracted extensive attention from coaches, scientists and athletes. The purpose of this study was to compare the differences between the long and short chasse steps in table tennis and evaluate risk factors related to injuries in the lower limb. Materials and Methods: Twelve male elite athletes performed forehand topspin strokes with long and short chasse steps in this study, respectively. The kinematics data of the lower-limb joints were measured by a Vicon motion analysis system. The electromyograms (EMG) of six lower-limb muscles were recorded using a myoelectricity system. Results: The key findings were that the angle change rate of the ankle in the long chasse step was faster with a larger range of motion (ROM) in the coronal and transverse planes. The hip was also faster in the sagittal and transverse planes but slower in the coronal plane compared with the short chasse step. In addition, the vastus medialis (VM) was the first activated muscle in the chasse step. Conclusions: The hip and ankle joints in the long chasse step and the knee joint in the short chasse step have higher susceptibility to injury. Moreover, tibialis anterior (TA), vastus medialis (VM) and gastrocnemius (GM) should be sufficiently stretched and warmed prior to playing table tennis. The results of this study may provide helpful guidance for teaching strategies and providing an understanding of potential sport injury mechanisms.
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Rendimiento Atlético/fisiología , Extremidad Inferior/fisiología , Tenis/lesiones , Tenis/fisiología , Adulto , Traumatismos del Tobillo , Articulación del Tobillo/fisiología , Atletas , Fenómenos Biomecánicos , Electromiografía , Lesiones de la Cadera , Articulación de la Cadera/fisiología , Humanos , Traumatismos de la Rodilla , Articulación de la Rodilla/fisiología , Masculino , Músculo Esquelético/fisiología , Músculo Cuádriceps/fisiología , Rango del Movimiento Articular/fisiología , Factores de Riesgo , Ejercicio de Calentamiento/fisiología , Adulto JovenRESUMEN
BACKGROUND: Prior to the 2017 table tennis season, each participant performed the anterior, posteromedial, and posterolateral the star excursion balance test (SEBT) reach distances in a randomized order. The aim of this study was to assess the effects of table tennis multi-ball training and dynamic balance on performance measures of the SEBT for the male and female. METHODS: The limb lengths of the 12 table tennis athletes were measured bilaterally in the study. Besides warm-up end, the data of this study were recorded at a regular interval at approximately 16 min for the entire multi-ball training session, and they were defined as Phase I, Phase II, Phase II, respectively. The Borg rating of perceived exertion (RPE) scale was used to document the degree of physical strain. RESULTS: Reaching distances showed a decrease with training progression in all directions. Compared with the male table tennis athletes, the females showed poorer dynamic posture control, particularly when the free limb was considered with the right-leg stance toward posterolateral and posteromedial directions in phase I. DISCUSSION: This study suggests that during table tennis multi-ball training the male should have a regulatory protocol to compensate the deficit observed in phase II, but the females should be given the protocol in phase I.
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BACKGROUND: The table tennis serve involves complex spatial movements combined with biomechanial characteristics. Although the differences in lower-limb biomechanial characteristics to a great extent influence the translational and spinning velocity of the ball when using the different styles of table tennis serve, few researchers have studied their mechanics. Therefore, the aim of this study was to investigate the differences in lower-limb activity between the squat and standing serves during a table tennis short serve. METHODS: Ten advanced female table tennis participants performed a squat serve and standing serve in random order. A Vicon motion analysis system and a Novel Pedar insole plantar pressure measurement system were used to record kinematics and kinetics data, respectively. RESULTS: Key findings from the study were that the squat serve not only showed significantly larger hip and knee flexion, as well as ankle dorsiflexion, it also showed significantly larger hip adduction and external knee rotation, with larger changing angular rate of the lower limb joints in the sagittal and the transverse planes when the two serving styles were compared. In addition, the force-time integral (FTI) was higher in the rear foot area for the standing serve. DISCUSSION: The results demonstrated that the squat serve needs higher lower limb drive during a table tennis short serve compared with a standing serve. These biomechanical considerations may be beneficial for table tennis athletes and coaches as a method of optimizing performance characteristics during both competition and training.