ABSTRACT Objective: MCM3AP-AS1 has been characterized as an oncogenic long non-coding RNA (lncRNA) in several cancers including papillary thyroid cancer (PTC), but its role in PTC has not been fully elucidated. Considering the critical role of lncRNAs in cancer biology, further functional analysis of MCM3AP-AS1 in PTC may provide novel insights into PTC management. Subjects and methods: Paired tumor and non-tumor tissues were collected from 63 papillary thyroid carcinoma (PTC) patients. Expression levels of MCM3AP-AS1 , miR-218 and GLUT1 in tissue samples were analyzed by qRT-PCR. Cell transfection was performed to explore the interactions among MCM3AP-AS1 , miR-218 and GLUT1 . Cell proliferation assay was performed to evaluate the effects of MCM3AP-AS1 and miR-218 on cell proliferation. Results: MCM3AP-AS1 accumulated to high levels in PTC tissues and was affected by clinical stage. MCM3AP-AS1 showed a positive correlation with GLUT1 across PTC tissues. RNA interaction prediction showed that MCM3AP-AS1 could bind to miR-218 , which can directly target GLUT1 . MCM3AP-AS1 and miR-218 showed no regulatory role regulating the expression of each other, but overexpression of MCM3AP-AS1 upregulated GLUT1 and enhanced cell proliferation. In contrast, overexpression of miR-218 downregulated GLUT1 and attenuated cell proliferation. In addition, miR-218 suppressed the role of MCM3AP-AS1 in regulating the expression of GLUT1 and cell proliferation. Conclusions: MCM3AP-AS1 may serve as a competing endogenous RNA of miR-218 to upregulate GLUT1 in PTC, thereby promoting cell proliferation. The MCM3AP-AS1/miR-218/GLUT1 pathway characterized in the present study might serve as a potential target to treat PTC.

Abstract Anthocyanin/polyvinyl alcohol/chitosan composite membrane was prepared by solution casting method using chitosan (CS) and polyvinyl alcohol (PVA) as matrix and natural pigment anthocyanin as filler. The structures of the composite films were characterized by Uv-visible reflectance spectrum (UV-VIS), Fourier infrared spectroscopy (FT-IR) and the scanning electron microscopy (SEM). The effects of adding anthocyanins on the physical properties, water resistance, degradation, antibacterial properties and pH responsiveness of the films were investigated. The experimental results showed that the prepared anthocyanin/polyvinyl alcohol/chitosan composite indicator films show color changes from pink to purple to blue and then to yellow-green when the pH value ranges from 2 to 14. The total color difference ΔE value is greater than 12. The antibacterial properties and other properties of the composite film can enhance by adding anthocyanin. The tensile strength of anthocyanin/polyvinyl alcohol/chitosan film is more than 70 MPa, which is larger than that of polyvinyl film and polyvinyl alcohol/chitosanfilm. The film has excellent physical, antibacterial properties and obvious pH response performance, making it ideal for food packaging.

Abstract Heigen is the root and rhizomes of Duhaldea Nervosa Anderberg., a traditional medicine food homology herb used to treat rheumatoid arthritis in China,but the potential active components and the underlying mechanism have not been clarified. In this study, the chemical compounds and the components absorbed into the blood from Heigen were assessed using ultra-high performance liquid chromatography coupled with quadrupole Orbitrap high-resolution mass spectrometry. 72 chemical constituents were identified in Heigen, 13 blood prototypical constituents, and 9 metabolites were found in serum samples after intragastric administration of Heigen extracts to rats. Then, using network pharmacology and molecule docking, 10 compounds were assumed to be potentially key active compounds against RA, which may be via the multi-component, multi-target and multi-pathway interaction mechanism of Heigen in the treatment of RA, and also provides a pharmacological basis for the treatment of RA.

ABSTRACT Introduction As a high-intensity physical sport, athletics can easily cause serious physical injuries and even psychological problems if not diagnosed after sports fatigue. Objective Study the relationship between sports fatigue and nutritional intervention in track and field. Methods One hundred track and field athletes in a province were investigated. Through literature survey, questionnaire survey, and other data testing, track and field athletes’ sports fatigue and nutritional status were analyzed to determine the necessary relationship between sports fatigue and nutritional intervention. Results The coach’s judgment of sports fatigue during athletes’ training is characterized by a lack of technical accuracy, leading to the decline of athletes’ physical recovery ability and aggravating sports fatigue to a certain extent. As a high-intensity physical exercise, athletics must diagnose sports fatigue in time and provide effective nutritional intervention. Conclusion The research shows that after high-intensity exercise, the diagnosis of sports fatigue in track and field athletes is of great importance in judging the athletes’ physical function, and scientific nutritional intervention plays an important role in athletes’ excessive physical function, improving their sports ability and relieving sports fatigue. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMEN Introducción Al ser un deporte físico de alta intensidad, el atletismo puede provocar fácilmente graves lesiones físicas e incluso problemas psicológicos si no se diagnostican a tiempo tras la fatiga deportiva. Objetivo Estudiar la relación entre la fatiga deportiva y la intervención nutricional en el atletismo. Métodos Se investigó a 100 practicantes de atletismo de una provincia. Mediante un estudio bibliográfico, un cuestionario y otras pruebas de datos, se analizó la fatiga deportiva y el estado nutricional de los atletas para averiguar la relación necesaria entre la fatiga deportiva y la intervención nutricional. Resultados El juicio del entrenador sobre la fatiga deportiva durante el entrenamiento de los atletas se caracteriza por la falta de precisión técnica, lo que conduce a la disminución de la capacidad de recuperación física de los atletas y agrava la fatiga deportiva en cierta medida. Como ejercicio físico de alta intensidad, el atletismo necesita un diagnóstico de la fatiga deportiva no sólo a tiempo, sino también una intervención nutricional eficaz. Conclusión La investigación muestra que, tras un ejercicio de alta intensidad, el diagnóstico de la fatiga deportiva de los atletas de atletismo es de gran importancia para juzgar la función física de los atletas, y la intervención nutricional científica desempeña un papel importante en la función física excesiva de los atletas, mejorando su capacidad deportiva y aliviando la fatiga deportiva. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

RESUMO Introdução Por ser um esporte físico de alta intensidade, o atletismo pode facilmente causar lesões físicas graves e até mesmo problemas psicológicos se não forem diagnosticáveis a tempo após a fadiga esportiva. Objetivo Estudar a relação entre a fadiga esportiva e a intervenção nutricional no atletismo. Métodos Foram investigados 100 praticantes de atletismo em uma província. Através de pesquisa bibliográfica, levantamento de questionários e outros testes de dados, a fadiga esportiva e o estado nutricional dos esportistas de atletismo foram analisados para descobrir a relação necessária entre a fadiga esportiva e a intervenção nutricional. Resultados O julgamento do treinador sobre a fadiga esportiva durante o treinamento dos atletas é caracterizado pela falta de precisão técnica, levando ao declínio da capacidade de recuperação física dos atletas e agravando a fadiga esportiva em certa proporção. Como um exercício físico de alta intensidade, o atletismo necessita de diagnóstico da fadiga esportiva não apenas no tempo, mas também de uma intervenção nutricional eficaz. Conclusão A pesquisa mostra que após o exercício de alta intensidade, o diagnóstico da fadiga esportiva dos praticantes de atletismo é de grande importância para julgar a função física dos atletas, e a intervenção nutricional científica desempenha um papel importante na função física excessiva dos atletas, melhorando sua capacidade esportiva e aliviando a fadiga esportiva. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

ABSTRACT Introduction: Strength quality can be divided into total strength, rapid strength, endurance strength, and reaction strength, among which rapid strength has been a much-discussed theme in sports industry research. Objective: Study the impacts of eccentric lower limb training on jumping ability in soccer athletes. Methods: A multifunctional centrifugal training device was used as a training tool, and the effect of eccentric training on rapid strength in soccer players was analyzed. Results: The average force of soccer players in the experimental group increased by about 524N, and the completion rate increased by about 76%. Both average strength and completion rate were significantly improved. Compared to the control group, the experimental group benefited more from the explosive power and kinetic indexes. There was also a significant improvement in the four indices of jumping ability, the three indices of sensitivity (except 15s step frequency), and eccentric training in the experimental group (P < 0.01). Conclusion: The proposed lower limb eccentric training resulted in a beneficial effect on the jumping ability of athletes. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMEN Introducción: La calidad de la fuerza puede dividirse en fuerza total, fuerza rápida, fuerza a la resistencia y fuerza de reacción, entre las cuales la fuerza rápida es un tema suficientemente discutido en las investigaciones de la industria del deporte durante los últimos años. Objetivo: Estudiar las repercusiones del entrenamiento excéntrico de los miembros inferiores en la capacidad de salto de los deportistas de fútbol. Métodos: Se utilizó un dispositivo de entrenamiento centrífugo multifuncional como herramienta de entrenamiento, y se analizó el efecto del entrenamiento excéntrico sobre la fuerza rápida en jugadores de fútbol. Resultados: La fuerza media de los futbolistas del grupo experimental aumentó en unos 524N, y la tasa de finalización aumentó en un 76%. Tanto la fuerza media como la tasa de finalización mejoraron significativamente. En comparación con el grupo de control, el grupo experimental obtuvo un mayor beneficio del índice de potencia explosiva y del índice cinético. También hubo una mejora significativa en los cuatro índices de capacidad de salto, los tres índices de sensibilidad (excepto la frecuencia de paso de 15s) y el entrenamiento excéntrico en el grupo experimental (P < 0,01) Conclusión: El entrenamiento excéntrico de las extremidades inferiores propuesto tuvo un efecto beneficioso en la capacidad de salto de los atletas. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

RESUMO Introdução: A qualidade da força pode ser dividida em força total, força rápida, força à resistência e força de reação, entre as quais a força rápida é um tema bastante discutido nas pesquisas da indústria esportiva pelos últimos anos. Objetivo: Estudar os impactos do treinamento excêntrico dos membros inferiores sobre a capacidade de salto nos atletas de futebol. Métodos: Foi utilizado um dispositivo de treinamento centrífugo multifuncional como instrumento de treino, analisou-se o efeito do treinamento excêntrico sobre a força rápida em jogadores de futebol. Resultados: A força média dos jogadores de futebol do grupo experimental aumentou em cerca de 524N, e a taxa de conclusão aumentou em cerca de 76%. Tanto a força média quanto a taxa de finalização foram significativamente aprimoradas. Em comparação com o grupo controle, o grupo experimental teve um benefício maior do índice de potência explosiva e índice cinético. Também houve melhora significativa nos quatro índices de habilidade de salto, nos três índices de sensibilidade (exceto a frequência de passos de 15s), e no treinamento excêntrico do grupo experimental (P < 0,01). Conclusão: O treinamento excêntrico proposto para membros inferiores resultou em um efeito benéfico sobre a capacidade de salto dos atletas. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

Abstract Objectives Metastasis is one of the biggest challenges in the management of Esophageal Squamous Cell Carcinoma (ESCC), of which molecular mechanisms remain elusive. The present study aimed to explore the roles and underlying mechanisms of Transmembrane protein 26 (TMEM26) in ESCC. Method TMEM26 expressions in tumorous and adjacent tissues from patients with ESCC and in normal esophageal epithelial and ESCC cell lines were detected by immunostaining and western blotting, respectively. The Epithelial-Mesenchymal Transition (EMT), a critical process during metastasis, was investigated by wound healing and Transwell assays, and EMT-related proteins were examined after the TMEM26 alteration in ESCC cell lines. NF-κB signaling activation and Tight Junction (TJ) protein expression were analyzed by western blotting and immunofluorescence, respectively. In vivo verification was performed on the liver metastatic murine model. Results Compared with non-cancerous esophageal tissues and cells, the TMEM26 expression level was higher in ESCC samples and cell lines, where the plasma membrane localization of TMEM26 was observed. The EMT-related processes of ESCC cells were suppressed by RNAi depletion of TMEM26 but aggravated by TMEM26 overexpression. Mechanistically, TMEM26 promoted NF-κB signaling to accelerate EMT in ESCC cells. The plasma membrane presentation and assembly of TJ proteins were impaired by TMEM26. Conclusion Overall, TMEM26 acts as a critical determinant for EMT in ESCC cells by disrupting TJ formation and promoting NF-κB signaling, which may be a potential therapeutic target for treating metastatic ESCC.

ABSTRACT Objective: To determine the absolute number of serum T lymphocytes and cytokine levels and the characteristics of patients with active pulmonary tuberculosis and to assess their effect on the immune status of these patients and their diagnostic and predictive value for tuberculosis. Methods: We included 1,069 patients with active tuberculosis, 51 patients with latent tuberculosis infection, and 600 health individuals. Absolute serum T-lymphocyte counts and cytokine levels were quantified. Results: T lymphocytes were significantly reduced in patients with active tuberculosis when compared with healthy individuals. The immune function of patients gradually decreased with age and was stronger in female patients than in males. Th1 cells expressed higher levels of cytokines than did Th2 cells. Logistic regression analysis showed that reduced CD3+ T, CD8+ T, and NK cell counts, as well as reduced IL-4 and IFN-g expression, were independent influencing factors for active tuberculosis. ROC analysis showed that the sensitivity and specificity of absolute CD3+ T and CD8+ T lymphocyte counts and combined factors were significantly higher than were those of IL-4 and IFN-g for diagnosing active tuberculosis. Conclusions: Serum T-lymphocyte counts and cytokine levels can assess the immune status of tuberculosis patients; they are also useful biomarkers for predicting and diagnosing tuberculosis.

RESUMO Objetivo: Determinar o número absoluto de linfócitos T séricos e os níveis de citocinas séricas, bem como as características, de pacientes com tuberculose pulmonar ativa e avaliar o efeito desses no estado imunológico desses pacientes e seu valor diagnóstico e preditivo para tuberculose. Métodos: Foram incluídos 1.069 pacientes com tuberculose ativa, 51 pacientes com tuberculose latente e 600 indivíduos saudáveis. Foram realizadas a contagem absoluta de linfócitos T séricos e a quantificação de citocinas séricas. Resultados: Os linfócitos T estavam significativamente reduzidos nos pacientes com tuberculose ativa em comparação com os indivíduos saudáveis. A função imunológica dos pacientes diminuiu gradativamente com a idade e mostrou-se mais forte nas mulheres do que nos homens. As células Th1 expressaram maiores níveis de citocinas do que as células Th2. A análise de regressão logística mostrou que contagens reduzidas de células T CD3+, T CD8+ e NK e expressão reduzida de IL-4 e IFN-g foram fatores de influência independentes para tuberculose ativa. A análise ROC mostrou que a sensibilidade e especificidade dos valores absolutos de linfócitos T CD3+ e T CD8+ e de fatores combinados foram significativamente maiores do que as da IL-4 e do IFN-g para o diagnóstico da tuberculose ativa. Conclusões: A contagem de linfócitos T séricos e os níveis de citocinas séricas podem avaliar o estado imunológico de pacientes com tuberculose; também são biomarcadores úteis na predição e diagnóstico da tuberculose.

Abstract Perianal fistula is a common complication of Crohn disease, and it is a great burden on the life and psychology of patients, but its treatment is still a difficult problem to face. In recent years, progress in the treatment of Crohn disease has progressed rapidly due to the advent of biological agents, but there has been a lack of research on perianal fistula in Crohn disease, and the direction of research has been scattered; therefore, the author reviews the traditional treatment of perianal fistula in Crohn disease in the context of the available literature and discusses emerging and potential therapeutic approaches. patients face years agents scattered therefore approaches

Abstract Clinically, methane is an anti-inflammatory gas used to treat organ damage. There is no extensive research on methane's repair of traumatic brain injury (TBI), so this study aims to investigate the role of methane and its potential mechanism. A rat TBI model was established by mechanical impact. SD rats were divided into four groups, including sham group, TBI group, 2 or 20 mL/kg methane-rich saline (MS) group. Morris water maze test revealed that MS improved cognitive function in TBI rats. HE and Nissl staining showed that MS reduced the blurring of brain tissues boundary, the number of necrotic plaques and neurons in TBI rats. In addition, ELISA revealed that MS restored the oxidative stress of TBI rats and reversed the inflammatory effect of TBI on brain cells, and TUNEL staining detected that MS inhibited cell apoptosis. Western blotting showed that MS downregulated Caspase-3 and Bax protein levels and upregulated Bcl-2 level. And MS inhibited phosphorylated expressions of Janus kinase 1 (JAK1), signal transducer and activator of the transcription (STAT1) and NF-κb-p65. In conclusion, MS improved cognitive function, reduced inflammatory response and oxidative stress and inhibited cell apoptosis to relieve rat TBI by blocking the activation of the JAK1/STAT1/NF-κb-p65 pathway.

Abstract Glutathione S-transferases (GSTs) are proteins synthesized in plants and responsible for their tolerance to environmental stresses. However, little information is available on the GST gene family of sweet potato, a globally important crop. The genetic evolution of GSTs in sweet potato remains unclear. The present study investigated the GST gene family in sweet potato by transcriptomic and comparative genomic analyses. A total of 51 GSTs were identified. Gene expression analysis showed differential expression patterns of the GSTs between two investigated varieties. Some GST expression levels were either up- or downregulated under oxidative, salinity and drought stresses. The results of the investigation provided new insights on the GST gene family in sweet potato, which may further the understanding of the roles of these genes in regulating abiotic stresses.

Abstract Melatonin is known to influence various physiological processes, including plant ripening; however, the effect of melatonin on postharvest blueberry fruit softening is unknown. Herein, the effects of melatonin at different concentrations (100, 300, and 500 μmol L-1) on the quality parameters, cell wall substances, cell-wall-degrading enzymes, and cell wall ultrastructure of blueberry fruits were investigated during low-temperature storage. Melatonin treatment was found to effectively delay the decline in fruit firmness, slow the loss of soluble solids and titratable acids, and decrease the respiration rate and decay rate of blueberry fruits. The blueberry fruits treated with 300 μmol L-1 melatonin exhibited the best quality. Melatonin treatment promoted anthocyanin accumulation, delayed ascorbic acid degradation, maintained a low relative membrane permeability in pulp, inhibited increases in lipoxygenase (LOX) activity, and reduced membrane lipid peroxidation. Moreover, melatonin controlled the formation of soluble pectin by inhibiting the activities of pectin methylesterase (PME), polygalacturonase (PG), cellulase (Cx), and β-glucosidase (β-Glu) while maintaining high contents of protopectin and cellulose. These results indicate that melatonin can effectively improve blueberry fruit quality and antioxidant capacity as well as and delay fruit softening by inhibiting the degradation of cell wall substances.

Abstract Objective To explore the molecular mechanism of neuropathologic damage induced by radiofrequency ablation at different temperatures. Methods This is basic research, and 36 SD rats were used to construct the neuropathological injury model. The rats were subjected to radiofrequency stimulation at different temperatures and were divided into 6 groups according to the temperature injury: 42°, 47°, 52°, 57°, 62°, and 67°C groups. Conduction time, conduction distance, and nerve conduction velocity were recorded after temperature injury. HE-staining was used to observe the histopathological morphology of the sciatic nerve. The expression of SCN9A, SCN3B, and NFASC protein in sciatic nerve tissue were detected by western blot. Results With the increase in temperature, nerve conduction velocity gradually decreased, and neurons were damaged when the temperature was 67°C. HE-staining showed that the degrees of degeneration of neurons in rats at 47°, 52°, 57°, 62°, and 67°C were gradually increased. The expression of SCN9A, SCN3B protein in 57°, 62°, 67°C groups were much higher than that of NC, 42°, 47°, 52°C groups. However, the expression of NFASC protein in 57°, 62°, 67°C groups was much lower than that of the NC, 42°, 47°, 52°C groups. Conclusion There was a positive correlation between temperature caused by the radiofrequency stimulation to neuropathological damage. The mechanism is closely related to the expression of SCN9A, SCN3B, and NFASC protein in nerve tissue caused by heat transfer injury.

RESUMO Contexto: devido a vários fatores incertos e inesperados da vida, como doenças, desastres naturais, acidentes de trânsito e defeitos congênitos, o número e a proporção de amputações de membros inferiores ainda estão aumentando por muitos motivos, portanto, a pesquisa sobre próteses de membros inferiores é particularmente importante. Objetivo: Este trabalho teve como objetivo estudar a relação entre o exercício em altitude e a função cardiopulmonar. Métodos: Um modelo de alterações anormais da função cardiopulmonar foi estabelecido e, em seguida, 40 praticantes de exercícios de platô foram selecionados, todos chegaram ao Tibete em março de 2017. A relação entre o volume de circulação pulmonar e a pressão interna no tórax foi observada e comparada. A relação entre o reflexo sensorial cardiopulmonar e a respiração do exercício (altitude) e a frequência cardíaca foi analisada. A comparação da função cardiopulmonar de indivíduos de diferentes gêneros foi implementada. Além disso, a influência de diferentes altitudes na função cardiopulmonar dos indivíduos e as mudanças na função cardiopulmonar dos indivíduos antes da partida e durante a primeira, segunda e terceira semanas após a partida foram observadas e comparadas. Resultados: I. À medida que a pressão na cavidade torácica aumentou, o volume de sangue da circulação pulmonar dos indivíduos diminuiu gradualmente, e a diminuição foi mais óbvia no estágio de pressão torácica −50 a 0. II. À medida que o coeficiente do reflexo cardiorrespiratório aumentou, a respiração dos indivíduos e a aceleração compensatória da frequência cardíaca apareceram. III. O rastreamento e o monitoramento dos indicadores cardiopulmonares dos indivíduos revelaram que, com o aumento da altitude, a pressão arterial média, a frequência respiratória e a frequência cardíaca dos indivíduos mostraram uma tendência ascendente, enquanto o valor de saturação de oxigênio no sangue mostrou uma tendência descendente. 4. Por mais alta que fosse a altitude, a pressão arterial média, a frequência respiratória e a frequência cardíaca monitoradas dos indivíduos em exercício foram significativamente superiores aos valores do indicador em repouso, enquanto o valor da saturação de oxigênio no sangue apresentou tendência oposta. V. A pressão arterial média, respiração e frequência cardíaca dos indivíduos na primeira semana foram maiores do que em outros períodos de tempo, mas a saturação de oxigênio no sangue foi relativamente menor. Na segunda e terceira semanas, as mudanças na função cardiopulmonar foram relativamente suaves (todos P <0,05). VI. As mudanças no índice de função cardiopulmonar de sujeitos de diferentes gêneros foram pequenas (p> 0,05). Conclusão: Por meio da modelagem, os resultados do ambiente de planalto sobre a função cardiopulmonar do corpo ficaram mais claros, e os dados dessas pesquisas forneceram referenciais teóricos para o treinamento do campo esportivo na área de planalto. Nível de evidência II; Estudos terapêuticos- investigação dos resultados do tratamento.

ABSTRACT Introduction: Due to various uncertain and unexpected factors in life such as diseases, natural disasters, traffic accidents, and congenital disabilities, the number and proportion of lower limb amputations are still rising for many reasons, so the research on lower limb prostheses is particularly important. Objective: This work aimed to study the relationship between altitude exercise and cardiopulmonary function. Methods: A model of abnormal changes in cardiopulmonary function was established, and then 40 plateau exercisers were selected, all of whom arrived in Tibet in March 2017. The relationship between pulmonary circulation volume and internal pressure in the chest was observed and compared. The relationship between cardiopulmonary sensory reflex and exercise (high altitude) breathing and heart rate was analyzed. A comparison of the cardiopulmonary function of subjects of different genders was implemented. Moreover, the influence of different altitudes on the subjects’ cardiopulmonary function and the subjects’ cardiopulmonary function changes before departure and during the first, second, and third week after departure were observed and compared. Results: I. As the pressure in the thoracic cavity increased, the subjects’ pulmonary circulation blood volume gradually decreased, and the decrease was most obvious in the stage of thoracic pressure −50 to 0. II. As the cardiorespiratory reflex coefficient increased, the subjects’ breathing and heart rate compensatory acceleration appeared. III. Tracking and monitoring of the subjects’ cardiopulmonary indicators revealed that with the increase in altitude, the subjects’ average arterial pressure, respiratory frequency, and heart rate all showed an upward trend, while the blood oxygen saturation value showed a downward trend. IV. No matter how high the altitude was, the average arterial pressure, respiratory rate, and heart rate monitored of the subjects under exercise were significantly superior to the indicator values under resting state. In contrast, the blood oxygen saturation value showed the opposite trend. V. The subjects’ average arterial pressure, respiration, and heart rate in the first week were higher than other periods, but the blood oxygen saturation was relatively lower. In the second and third weeks, the changes in cardiopulmonary function were relatively smooth (all P<0.05). VI. The changes in the index of the cardiopulmonary function of subjects of different genders were small (p>0.05). Conclusion: Through modeling, the results of the plateau environment on the cardiopulmonary function of the body were made clearer, and these research data provided theoretical references for the training of the sports field in the plateau area. Level of evidence II; Therapeutic studies - investigation of treatment results.

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RESUMO Introdução: A força centrífuga é um elemento importante na qualidade de força. O desenvolvimento da força centrífuga muscular pode, efetivamente, aumentar a estabilidade dos membros inferiores e reduzir o risco de lesões. Objetivo: Explorar as características da força contrátil do músculo flexor no treinamento de força e de reabilitação, e os músculos extensores da junta do joelho em atletas com diferentes velocidades de força centrípeta. Métodos: O grupo muscular da articulação do joelho de oito saltadores de primeiro escalão do sexo masculino, e oito saltadores de segundo escalão do sexo masculino foi testado por contração centrífuga isocinética. A velocidade de teste angular foi de 60 °/s, 120 °/s, 240 °/s, e os índices incluíram torque de pico, torque de pico relativo (torque de pico/peso corporal) e a razão extensão-flexão de torque de pico. Resultados: Na contração centrífuga do grupo muscular da articulação do joelho (P < 0,05), os saltadores de segundo escalão devem aumentar a habilidade do grupo muscular flexor do joelho da perna de arranque. No caso da contração centrífuga de velocidade constante (P < 0,01), o tempo de arranque deve ser reduzido, ou seja, a velocidade de arranque deve ser acelerada. Conclusões: A diferença nos resultados dos testes isocinéticos do músculo da junta do joelho é uma das razões para a diferença na contratilidade muscular flexor e extensor da junta do joelho sob forças de velocidade diferentes em saltadores. Nível de evidência II; Estudos terapêuticos – investigação de resultados de tratamento.

ABSTRACT Introduction: Centrifugal strength is an important element for strength quality. Developing muscle centrifugal strength can effectively increase the stability of lower limbs and reduce the risk of injury. Objective: To explore the characteristics of contractile force of flexor ahods in strength training and rehabilitation training, and the extensor muscles of the knee joint in athletes with different speeds of centripetal force. Methods: The knee joint muscle group of 8 first-level male high jumpers and 8 second-level male high jumpers were tested by isokinetic centrifugal contraction; the angular test velocity was 60 °/s, 120 °/s, 240 °/s, and the indexes included peak torque, relative peak torque (peak torque/body weight), and the peak torque flexural extension ratio. Results: With the centrifugal contraction of the knee joint muscle group (P < 0.05), the second-level high jumpers should increase the ability of the knee flexor muscle group of the take-off leg. In the case of constant velocity centrifugal contraction (P < 0.01), taking off time must be reduced, that is, taking off speed must be accelerated. Conclusions: The difference in the knee joint muscle isokinetic test results is one of the reasons for the difference in knee joint flexor and extensor muscle contractility under the different speed forces of high jumpers. Level of evidence II; Therapeutic studies - investigation of treatment results.

Resumen Introducción: La fuerza centrífuga es un elemento importante en la calidad de fuerza. El desarrollo de la fuerza centrífuga muscular puede efectivamente aumentar la estabilidad de los miembros inferiores y reducir el riesgo de lesiones. Objetivo: Explorar las características de la fuerza contráctil del músculo flexor en el entrenamiento de fuerza y de rehabilitación, y los músculos extensores de la articulación de la rodilla en atletas con diferentes velocidades de fuerza centrípeta. Métodos: Se testó el grupo muscular de la articulación de la rodilla de 8 saltadores de primer escalafón del sexo masculino, y 8 saltadores de segundo escalafón del sexo masculino por contracción centrífuga isocinética. La velocidad de prueba angular fue de 60 °/s, 120 °/s, 240 °/s, y los índices incluyeron torque de pico, torque de pico relativo (torque de pico/peso corporal) y la razón extensión-flexión de torque de pico. Resultados: En la contracción centrífuga del grupo muscular de la articulación de la rodilla (P<0,05), los saltadores de segundo escalafón deben aumentar la habilidad del grupo muscular flexor de la rodilla de la pierna de arrancada. En el caso de la contracción centrífuga de velocidad constante (P<0,01), el tiempo de arrancada debe reducirse, o sea, la velocidad de arrancada debe acelerar. Conclusiones: La diferencia en los resultados de las pruebas isocinéticas del músculo de la articulación de la rodilla es una de las razones para la diferencia en la contractilidad muscular flexor y extensor de la articulación de la rodilla bajo fuerzas de velocidad diferentes en saltadores. Nivel de evidencia II; Estudios terapéuticos – investigación de resultados de tratamiento.