Effect of different decontamination agents on the bond strength of CAD/CAM blocks and repair composite materials / Efecto de diferentes agentes descontaminantes sobre la resistencia de unión de bloques CAD/CAM y resinas compuestas

Abstract The purpose of this study was to examine the effect of different decontamination agents on the bond strength of saliva-contaminated CAD/CAM blocks and repair composite materials. Two hunderd eighty 3-mm-thick specimens were prepared from four different CAD/CAM materials: Katana Zirconia UTML disc, IPS e.max CAD block, Shofu block, and Vita Enamic block. Each material was divided into seven different subgroups (N=70). Group 1 had a clean surface. The other groups were comprised of the samples, which were contaminated with human saliva: group 2: negative control (non-cleaned); group 3: cleaned with water spray; group 4: cleaned with 70% ethanol; group 5: cleaned with Ivoclean; group 6: cleaned with Katana Cleaner; and group 7: cleaned with phosphoric acid. After the decontamination protocols, the resin composite cylinders were bonded to the CAD/CAM surfaces with a thin layer of dual-cured resin cement. The samples were stored for 24 hours at 37°C in distilled water. Then, they were subjected to a shear bond strength test (SBS). The values were recorded, and fracture types were evaluated using a microscope. Data were analyzed using two-way ANOVA and Tukey's post-hoc test. Generally, all decontaminating agents improved the SBS of composites to Katana Zirconia UTML, IPS e.max, and Vita Enamic materials (p<0.05). However, for Shofu materials, group 6 samples exhibited significantly higher bond strength values as compared with group 2 samples (p=0.026). The highest SBS values were seen in the phosphoric acid-treated group in Katana zirconia materials (26.45 ± 9.38 MPa), whereas the lowest values were seen in group 2 samples in Shofu materials (13.17±3.40 MPa). Each decontaminant agent improved the bond strength of composites to the contaminated CAD/CAM materials. If saliva is not cleaned before adhesive procedure, SBS values may decrease. All decontamination agents can be used safely on zirconia, lithium-disilicate glass-ceramic, hybrid ceramic, and polymer-infiltrated ceramic surfaces.

Resumen El propósito de este estudio fue examinar el efecto de diferentes agentes descontaminantes sobre la fuerza de unión de bloques CAD/CAM contaminados con saliva y materiales compuestos de reparación. Se prepararon doscientas ochenta muestras de 3 mm de espesor a partir de cuatro materiales CAD/CAM diferentes: disco Katana Zirconia UTML, bloque IPS e.max CAD, bloque Shofu y bloque Vita Enamic. Cada material se dividió en siete subgrupos diferentes (N=70). El grupo 1 tenía una superficie limpia. Los otros grupos estaban compuestos por muestras que estaban contaminadas con saliva humana: grupo 2: control negativo (no limpio); grupo 3: limpiado con agua pulverizada; grupo 4: limpiado con etanol al 70%; grupo 5: limpiado con Ivoclean; grupo 6: limpiado con Katana Cleaner; y grupo 7: limpiado con ácido fosfórico. Después de los protocolos de descontaminación, los cilindros de composite de resina se adhirieron a las superficies CAD/CAM con una fina capa de cemento de resina de curado dual. Las muestras se almacenaron durante 24 horas a 37°C en agua destilada. Luego, fueron sometidos a una prueba de resistencia al corte (SBS). Se registraron los valores y se evaluaron los tipos de fracturas utilizando un microscopio. Los datos se analizaron mediante ANOVA de dos factores y la prueba post-hoc de Tukey. En general, todos los agentes descontaminantes mejoraron el SBS de los composites con los materiales Katana Zirconia UTML, IPS e.max y Vita Enamic (p<0,05). Sin embargo, para los materiales Shofu, las muestras del grupo 6 exhibieron valores de fuerza de unión significativamente más altos en comparación con las muestras del grupo 2 (p=0,026). Los valores más altos de SBS se observaron en el grupo tratado con ácido fosfórico en materiales de circonio Katana (26,45 ± 9,38 MPa), mientras que los valores más bajos se observaron en las muestras del grupo 2 en materiales Shofu (13,17 ± 3,40 MPa). Cada agente descontaminante mejoró la fuerza de unión de los composites a los materiales CAD/CAM contaminados. Si no se limpia la saliva antes del procedimiento adhesivo, los valores de SBS pueden disminuir. Todos los agentes descontaminantes se pueden utilizar de forma segura en superficies de circonio, cerámica de vidrio de disilicato de litio, cerámica híbrida y cerámica con infiltraciones de polímeros.

La preparación especial de fuerza rápida en balistas con discapacidad físico-motriz por amputación

En el Campeonato Nacional de Paratletismo, en Cuba, los resultados competitivos de las balistas con discapacidad físico-motriz por amputación muestran un decrecimiento, en varias categorías. Se detectaron insuficiencias en la dosificación de las cargas, en la utilización de métodos, medios y procedimientos; además de una inadecuada orientación metodológica. Se trazó como objetivo diseñar una metodología para la planificación de la capacidad fuerza rápida en la etapa de preparación especial de balistas con discapacidad físico-motriz por amputación. Se realizó una investigación de tipo descriptiva y cuantitativa en el periodo comprendido entre el 2019-2022, el estudio se centró en el proceso de planificación y entrenamiento de la fuerza rápida en la etapa de preparación especial analizado y descrito, a través de métodos empíricos como la revisión de documentos, encuesta, entrevista y la triangulación metodológica, ello permitió evaluar su estado actual. Colaboraron como muestra atletas, entrenadores y directivos de nivel provincial y nacional. La metodología propuesta es viable y factible, con una efectividad esperada para el contexto deportivo actual y con posibilidades de generalización en otros eventos de lanzamiento. La propuesta diseñada enriquece la teoría del entrenamiento deportivo en atletas con discapacidad.

Nos Campeonatos Nacionais de Paratletismo em Cuba, os resultados competitivos dos balistas com deficiências físico-motoras por amputação mostram uma diminuição em várias categorias. Foram detectadas insuficiências na dosagem de cargas, no uso de métodos, meios e procedimentos, bem como uma orientação metodológica inadequada. O objetivo foi elaborar uma metodologia para o planejamento da capacidade de força rápida na fase de preparação especial de balistas com deficiência físico-motora decorrente de amputação. Foi realizada uma pesquisa descritiva e quantitativa no período entre 2019-2022, o estudo focou no processo de planejamento e treinamento da força rápida na fase de preparação especial analisada e descrita, por meio de métodos empíricos como revisão de documentos, pesquisa, entrevista e triangulação metodológica, o que permitiu avaliar seu estado atual. Atletas, técnicos e gerentes em nível provincial e nacional colaboraram como amostra. A metodologia proposta é viável e factível, com uma eficácia esperada para o contexto esportivo atual e com possibilidades de generalização em outros eventos de arremesso. A proposta elaborada enriquece a teoria do treinamento esportivo em atletas com deficiências.

In the National Para-Athletics Championship in Cuba, the competitive results of shot put athletes with physical-motor disabilities due to amputation show a decrease in several categories. Deficiencies were detected in the dosage of loads, in the use of methods, means and procedures; in addition to inadequate methodological guidance. The objective was to design a methodology for planning rapid strength capacity in the special preparation stage of shot put athletes with physical - motor disabilities due to amputation. A descriptive and quantitative research was carried out in the period between 2019-2022, the study focused on the planning and training process of rapid strength in the special preparation stage analyzed and described, through empirical methods such as the review of documents, survey, interview and methodological triangulation made it possible to evaluate its current state. Athletes, coaches and managers from provincial and national levels collaborated as a sample. The proposed methodology is viable and feasible, with expected effectiveness for the current sporting context and with possibilities of generalization in other throwing events. The designed proposal enriches the theory of sports training in athletes with disabilities.

Different Body Partialization Procedures Considering Maximum Strength and Explosiveness: Factorial Analysis Approach / Diferentes Procedimientos de Parcialización Corporal Considerando Fuerza Máxima y Explosividad: Enfoque de Análisis Factorial

SUMMARY: The aim of this study was to determine the sensitivity of different methods of partialization, in terms of different body component indices in relation to indicators of strength and explosiveness. The research involved 187 subjects who were divided into two groups based on sex. This research consisted of measuring body composition characteristics by multichannel bioimpedance analysis (BIA) InBody 720, as well as contractile characteristics of different muscle groups with tenziometric Dinamometry method. Based on the results of the factor analysis we found that regardless of the sex the most sensitive variable for partialization of absolute body isometric strength variable (ABiS) is partialization by allometric scaling (0.964 for females and 0.947 for males explained factor variance). However, in the case of absolute body isometric explosiveness (ABiE), the results of this study have demonstrated that partialization relative to skeletal muscle mass according to the body longitudinality - skeletal muscle mass index (SMMI) is the methodological choice disregarding the sex (0.982 for females and 0.980 for males explained factor variance). The results of the study have shown that for the purpose of scaling the maximal strength relative to body composition, the allometric method can be considered as a choice, while for the partialization of maximal isometric explosiveness skeletal muscle mass index is the best choice insensitive of the sex.

El objetivo de este estudio fue determinar la sensibilidad de distintos métodos de parcialización, en términos de diferentes índices de componentes corporales en relación a los indicadores de fuerza y explosividad. En la investigación participaron 187 sujetos que se dividieron según el sexo en dos grupos. Esta investigación consistió en medir las características de composición corporal mediante análisis de bioimpedancia multicanal (BIA) InBody 720, así como las características contráctiles de diferentes grupos musculares con el método de Dinamometría tenciométrica. Con base en los resultados del análisis factorial, encontramos que, independientemente del sexo, la variable más sensible para la parcialización de la variable de fuerza isométrica corporal absoluta (ABiS) fue la parcialización mediante escala alométrica (0,964 para las mujeres y 0,947 para los hombres). Sin embargo, en el caso de la explosividad isométrica corporal absoluta (ABiE), los resultados de este estudio han demostrado que la parcialización relativa a la masa del músculo esquelético según la longitudinalidad del cuerpo - índice de masa del músculo esquelético (SMMI) es la opción metodológica sin tener en cuenta el sexo (0,982 para las mujeres y 0,980 para los hombres). Los resultados del estudio han demostrado que para escalar la fuerza máxima en relación con la composición corporal, el método alométrico puede considerarse como una opción, mientras que para la parcialización de la explosividad isométrica máxima, el índice de masa del músculo esquelético es la mejor opción independiente del sexo.

Effects of traditional concurrent training and multicomponent training composed by strength training and dance classes on functional and cognitive capacity of older adults: a study protocol / Efeitos do treinamento combinado tradicional e do treinamento multicomponente composto por treinamento de força e aulas de dança na capacidade funcional e cognitiva de idosos: protocolo de estudo

The combination of strength and aerobic training (concurrent training - TG) has been a widely used intervention for improving health outcomes. Also, dance has been well described as a great aerobic activity and can be an interesting option to compose an alternative multicomponent training pro-gram. Therefore, the aim of the present protocol study is to describe the methods that will be used in a randomized controlled trial (RCT) design to identify and compare the impacts of traditional TG composed by strength and aerobic training and a multicomponent training consisting of strength training combined with dance classes (DG) on functional and cognitive capacity and quality of life of older people. The sample of RCT will consist of men and women aged between 60 and 75 years. Both interventions will occur twice a week for 12 weeks with progressive intensity and volume. Functional capacity will be assessed by gait, balance, sitting and standing and climbing tests. Strength will be assessed through one repetition maximum test (1RM) in knee extension exercise, and handgrip using a hand dynamometer. Muscle thickness will be assessed using quadriceps ultrasound. Muscle power will be assessed in the knee extension exercise at 30 and 70% of 1RM using an encoder. Aerobic capacity will be assessed using the 6-minute walk test. Quality of life and cognitive performance will be assessed by questionnaires. Comparisons between groups over time will be carried out using Generalized Estimating Equations with a significance level of p<0.01. This protocol follows the rec-ommendations of SPIRIT-2013.

A combinação de treinamento de força e aeróbico (treinamento combinado - TC) tem sido uma interven-ção amplamente utilizada para melhorar desfechos de saúde. Além disso, a dança tem sido bem descrita na literatura como uma ótima atividade aeróbica e pode ser uma opção interessante para compor um programa alternativo de treinamento multicomponente. Portanto, o objetivo do presente protocolo de estudo é descrever os métodos que serão utilizados em um ensaio clínico randomizado (ECR) que visa identificar e comparar os impactos do TC tradicional composto por treinamento de força e aeróbico e de um treinamento multi-componente composto por treinamento de força combinado com aulas de dança sobre capacidade funcional, cognitiva e qualidade de vida de idosos. A amostra do ECR será composta por homens e mulheres com idade entre 60 e 75 anos. Ambas as intervenções ocorrerão duas vezes por semana durante 12 semanas com intensidade e volume progressivos. A capacidade funcional será avaliada por meio de testes de marcha, equilíbrio, sentar e levantar e subir escadas. A força será avaliada por meio do teste de uma repetição máxima (1RM) no exercício de extensão de joelhos e por meio do teste de preensão palmar com o dinamômetro manual. A espessura muscular será avaliada por meio de ultrassonografia do quadríceps. A potência muscular será ava-liada no exercício de extensão de joelhos a 30 e 70% de 1RM por meio de um transdutor linear de posição. A capacidade aeróbica será avaliada por meio do teste de caminhada de 6 minutos. A qualidade de vida e o desempenho cognitivo serão avaliados por meio de questionários. As comparações entre os grupos ao longo do tempo serão realizadas por meio de Equações de Estimativas Generalizadas com nível de significância p<0,01. Este protocolo segue as recomendações do SPIRIT-2013.

CAD/CAM Materials for Endocrown Restorations: Evaluation of Microhardness, Flexural Strength, and Surface Characterization / Materiais CAD/CAM para Restaurações Endocrowns: Avaliação da Microdureza, Resistência à Flexão e Caracterização Superficial

Endocrowns have emerged as a promising option for restoring endodontically treated teeth, offeringa restorable fracture scenario. However, regarding the choice of material and its fracture resistance, there are gaps in the literature regarding the best indication. The objective of this research was to evaluate and compare the effect of restorative materials for CAD-CAM in the manufacture of endocrown restorations, through an in Vitro study on hardness and fracture resistance. For the study, CAD-CAM blocks were transformed into discs 12 mm in diameter and 1.2 mm thick (specimens). Three restorative materials were evaluated and distributed into experimental groups (N=12 specimens): Leucita- Reinforced Ceramic/ IPS Empress CAD (MRleu), Lithium Disilicate/ IPS Emax CAD (MRdis) and Nanoceramic Resin /Lava Ultimate (MRres). These restorative materials were evaluated for morphology (N=1) by Scanning Electron Microscopy (SEM) and surface chemistry (N=1) by dispersive energy spectroscopy (EDS). The specimens were evaluated when the Vikers micro hardness (N=1) with a load of 1kg and 10 indentations, as well as the resistance to biaxial flexion (N=10) at a test speed of 0.5 mm/min. After the fracture occurred, the fragments were examined under a stereomicroscope. The results were tabulated and analyzed using the Minitab statistical program. The results showed that the MRdis material demonstrated superior results in relation to hardness (P=0.000) and biaxial bending resistance (P=0.000), followed by MRleu and finally the MRres. The presence of inorganic particles on an organic matrix and the presence of Zirconium (Zr) stands out in Lava Ultimate. It was concluded that restorative materials for CAD-CAM in the manufacture of Endocrowns restorations have a significant effect on hardness and mechanical strength.Endocrowns have emerged as a promising option for restoring endodontically treated teeth, offeringa restorable fracture scenario. However, regarding the choice of material and its fracture resistance, there are gaps in the literature regarding the best indication. The objective of this research was to evaluate and compare the effect of restorative materials for CAD-CAM in the manufacture of endocrown restorations, through an in Vitro study on hardness and fracture resistance. For the study, CAD-CAM blocks were transformed into discs 12 mm in diameter and 1.2 mm thick (specimens). Three restorative materials were evaluated and distributed into experimental groups (N=12 specimens): Leucita- Reinforced Ceramic/ IPS Empress CAD (MRleu), Lithium Disilicate/ IPS Emax CAD (MRdis) and Nanoceramic Resin /Lava Ultimate (MRres). These restorative materials were evaluated for morphology (N=1) by Scanning Electron Microscopy (SEM) and surface chemistry (N=1) by dispersive energy spectroscopy (EDS). The specimens were evaluated when the Vikers micro hardness (N=1) with a load of 1kg and 10 indentations, as well as the resistance to biaxial flexion (N=10) at a test speed of 0.5 mm/min. After the fracture occurred, the fragments were examined under a stereomicroscope. The results were tabulated and analyzed using the Minitab statistical program. The results showed that the MRdis material demonstrated superior results in relation to hardness (P=0.000) and biaxial bending resistance (P=0.000), followed by MRleu and finally the MRres. The presence of inorganic particles on an organic matrix and the presence of Zirconium (Zr) stands out in Lava Ultimate. It was concluded that restorative materials for CAD-CAM in the manufacture of Endocrowns restorations have a significant effect on hardness and mechanical strength. (AU)

As endocrowns surgiram como uma alternativa favorável para a restauração de dentes tratados endodonticamente, e se apresentam em um cenário de fratura restaurável. No entanto, em relação ao material de escolha e sua resistência à fratura existem lacunas na literature sobre a melhor indicação. O objetivo dessa pesquisa foi avaliar e comparar o efeito de materiais restauradores para CAD-CAM na confecção de restaurações endocrowns, através de um estudo in vitro sobre dureza e resistência à fratura. Para realização do estudo, blocos para CAD-CAM foram transformados em discos com 12 mm de diâmetro e 1,2 mm de espessura (espécimes). Três materiais restauradores foram avaliados e distribuídos em grupos experimentais (N=12 espécimes): Cerâmica Reforçada por Leucita/ IPS Empress CAD (MRleu), Dissilicato de Lítio/ IPS Emax CAD (MRdis) e Resina Nanocerâmica /Lava Ultimate (MRres). Estes materiais restauradores foram avaliados quanto à morfologia (N=1) através de Microscopia Eletrônica de Varredura (MEV) e química superficial (N=1) pela Espectroscopia de energia dispersiva (EDS). Os espécimes foram avaliados quanto à microdureza Vikers (N=1) com uma carga de 1kg e 10 indentações, como também em relação a resistência à flexão biaxial (N=10) em uma velocidade de ensaio de 0,5 mm/min. Os fragmentos após a fratura foram observados em estereomicroscópio. Os dados obtidos foram tabulados e analisados no programa estatístico Minitab. Os resultados observados mostraram que o material MRdis obteve resultados superiores em relação a dureza (P=0,000) e a resistência à flexão biaxial (P=0,000), seguido pelo MRleu e por fim o MRres. Destaca-se na Lava Ultimate a presença de partículas inorgânicas sobre uma matriz orgânica, além da presença de Zircônio (Zr). Conclui-se que materiais restauradores para CAD-CAM na confecção de restaurações Endocrowns apresentam efeito significativo quanto a dureza e resistência mecânica. (AU)

Valores de referencia para el 1-minute sit-to-stand test en pacientes pediátricos con artritis idiopática juvenil / Reference values for the 1-minute sit-to-stand test in pediatric patients with juvenile idiopathic arthritis

Introducción: los niños con artritis idiopática juvenil (AIJ) experimentan períodos de dolor e inmovilidad que afectan sus capacidades condicionales. Objetivos: describir los valores de referencia para el 1-minute Sit-to-Stand Test(1-STS; test de 1 minuto de sentarse y pararse) en niños con AIJ como evaluación de la capacidad aeróbico-funcional y de la fuerza muscular de los miembros inferiores (MMII).Materiales y métodos: se realizó un estudio observacional que incluyó a 15 niños con AIJ de entre 5 y 16 años. Se evaluó su rendimiento en el 1-STS. Resultados: se encontró una correlación positiva significativa entre el 1-STS y el test de la marcha de 6 minutos (r=0,56; p=0,03), como con el índice de capacidad funcional (CAPFUN) (r=0,54; p=0,03). No se observaron correlaciones significati-vas entre el Childhood Health Assessment Questionnaire (CHAQ) y el 1-STS (r=-0,21; p=0,44), tampoco con el Juvenile Arthritis Disease Activity Score (JADAS-10) (p=0,83). Conclusiones: el 1-STS parece prometedor para medir la capacidad aeróbi-co-funcional y la fuerza muscular de los miembros inferiores en niños con AIJ oligoarticular.

Introduction: children with juvenile idiopathic arthritis (JIA) experience periods of pain and immobility that affect their physical capacities. Objectives: to describe reference values for the 1-minute sit to stand test (1-STS) in children with JIA as an assessment of aerobic-functional capacity and lower limb muscle strength.Materials and methods: an observational study was conducted, including 15 children with JIA aged between 5 and 16 years. Their performance in the 1-STS was assessed. Results: a significant positive correlation was found between the 1-STS and the 6-Minute Walk Test (r=0,56; p=0,03), as well as with the Functional Capacity Index (CAPFUN) (r=0,54; p=0,03). No significant correlations were observed between the Childhood Health Assessment Questionnaire (CHAQ) and the 1-STS (r=-0,21; p=0,44), nor with the Juvenile Arthritis Disease Activity Score (JADAS-10) (p=0,83). Conclusions: the 1-STS appears promising for assessing aerobic-functional capacity and lower limb muscle strength in children with oligoarticular JIA.

Quality of life and strength, but not cytokines, are associated with DAS-28 in active and inactive rheumatoid arthritis / Qualidade de vida e força, porém não as citocinas, estão associadas ao DAS-28 em pacientes com artrite reumatoide na fase ativa e inativa

Objective: Evaluate and correlate data between relevant cytokines, disease progression, and handgrip and quality of life among RA patients at different stages of disease progression. Method: Thirty-three RA patients were recruited for analysis, using comparisons and correlations, between levels of circulating cytokines (IFN-γ, TNF-α, IL-4, IL-6, IL-10, IL-17, IL-1ß, and TNF receptors I and II), activity of the disease (evaluated using the DAS-28), handgrip (Hydraulic dynamometer), and quality of life (SF-36). Result: RA patients in different disease stages showed increases of IL-6 and IL-10 compared control group. Positive correlation between IL-6 with TNF-α, and IL-4 with IL-10 was found. Handgrip strength and quality of life were not related to cytokine levels. However, remission patients had better strength and quality of life indices compared to the active patients. In addition, handgrip of the non-dominant side, physical functions, role limitations physical health, pain, energy/fatigue and social functions have a negative correlation with the DAS28-PCR. Conclusion: High levels of IL-6 and IL-10 were observed in the chronic RA patients, but the values did not show correlation with disease activity, handgrip strength and quality of life. Disease activity show correlation with handgrip strength and quality of life. Furthermore, remission patients had better strength and quality of life indices compared to the active patients.

Objetivo: Avaliar e correlacionar dados entre citocinas relevantes, progressão da doença, preensão manual e qualidade de vida entre pacientes com AR em diferentes estágios de progressão da doença. Método: Trinta e três pacientes com AR foram recrutados para análise, por meio de comparações e correlações, entre níveis de citocinas circulantes (IFN-γ, TNF-α, IL-4, IL-6, IL-10, IL-17, IL-1ß e receptores de TNF-I e -II), atividade da doença (avaliada pelo DAS-28), preensão manual (dinamômetro hidráulico) e qualidade de vida (SF-36). Resultado: Pacientes com doença ativa e inativa apresentaram aumento de IL-6 e IL-10 comparados ao grupo controle. Foi encontrada correlação positiva entre IL-6 com TNF-α e IL-4 com IL-10. A força de preensão e a qualidade de vida não relacionaram aos níveis de citocinas. Entretanto, pacientes em remissão apresentaram melhores índices de força e qualidade de vida comparados aos pacientes com doença ativa. Além disso, preensão manual do lado não dominante, e quesitos dos SF-36, apresentam correlação negativa com o DAS28-PCR. Conclusão: Foram observados níveis elevados de IL-6 e IL-10 nos pacientes com AR crônica, mas os valores não mostraram correlação com DAS-28, força de preensão manual e SF-36. A atividade da doença apresenta correlação com força de preensão manual e qualidade de vida. Além disso, os pacientes em remissão apresentaram melhores índices de força e qualidade de vida em comparação aos pacientes ativos.

Normative Data of Handgrip Strength in Macedonian Children and Adolescents According to Chronological and Biological Age / Datos Normativos de la Fuerza de Prensión Manual en Niños y Adolescentes Macedonios Según la Edad Cronológica y Biológica

SUMMARY: The handgrip strength is used as a means of individual's health prediction during life. It is used as an indicator of the nutrition status, bone fragility, presence of sarcopenia and it correlates with certain diseases and clinical complications. The research goal was to analyze the results of the hand dynamometry test, based on the chronological and biological age, and to offer normative and referent standards about children and adolescents from the Republic of North Macedonia. The study was conducted on a sample of 4031 respondents of both sexes at the age 6-14 years. In order to achieve the research goals, the measured characteristics were of the weight, height, sitting height and handgrip strength. The body mass index and biological maturity values (APHV) were obtained by using formulas. On the basis of the obtained results, it can be concluded that statistically significant differences in handgrip strength are established between the boys and girls of all age categories. Also, statistically significant differences between boys and girls are established in the hand dynamometry test of all APHV levels. In general, the use of the APHV allows a better categorization of the performance of the studied children and adolescents. With boys, the correlation between the chronological age and test was 68 %, and with girls - 77 %. The normative referent standards of the hand dynamometry test are presented in percentiles for both sexes. Thye hand dynamometry test's results during childhood and adolescence should be analyzed and interpret on the basis of biological age, and not on the chronological age. These tools can help specialists who work with children and adolescents in ethnic and epidemiological context.

La fuerza de prensión se utiliza como medio para predecir la salud del individuo durante la vida. Se utiliza como indicador del estado nutricional, fragilidad ósea, presencia de sarcopenia y se correlaciona con determinadas enfermedades y complicaciones clínicas. El objetivo de la investigación fue analizar los resultados de la prueba de dinamometría manual, con base en la edad cronológica y biológica, y ofrecer estándares normativos y referentes sobre niños y adolescentes de la República de Macedonia del Norte. El estudio se realizó en una muestra de 4031 encuestados de ambos sexos con edades comprendidas entre 6 y 14 años. Para lograr los objetivos de la investigación, las características medidas fueron el peso, la altura, la altura al sentarse y la fuerza de prensión. El índice de masa corporal y los valores de madurez biológica (APHV) se obtuvieron mediante fórmulas. Sobre la base de los resultados obtenidos, se puede concluir que se establecen diferencias estadísticamente significativas en la fuerza de prensión manual entre niños y niñas de todas las categorías de edad. Asimismo, se establecen diferencias estadísticamente significativas entre niños y niñas en la prueba de dinamometría manual de todos los niveles APHV. En general, el uso del APHV permite una mejor categorización del desempeño de los niños y adolescentes estudiados. En los niños, la correlación entre la edad cronológica y la prueba fue del 68 %, y en las niñas, del 77 %. Los estándares normativos referentes de la prueba de dinamometría manual se presentan en percentiles para ambos sexos. Los resultados de la prueba de dinamometría manual durante la infancia y la adolescencia deben analizarse e interpretarse en función de la edad biológica y no de la edad cronológica. Estas herramientas pueden ayudar a los especialistas que trabajan con niños y adolescentes en un contexto étnico y epidemiológico.

Valores de referencia para el 1-minute sit-to-stand test en pacientes pediátricos con artritis idiopática juvenil / Reference values for the 1-minute sit-to-stand test in pediatric patients with juvenile idiopathic arthritis

Resumen Introducción: los niños con artritis idiopática juvenil (AIJ) experimentan períodos de dolor e inmovilidad que afectan sus capacidades condicionales. Objetivos: describir los valores de referencia para el 1-minute Sit-to-Stand Test (1-STS; test de 1 minuto de sentarse y pararse) en niños con AIJ como evaluación de la capacidad aeróbico-funcional y de la fuerza muscular de los miembros inferiores (MMII). Materiales y métodos: se realizó un estudio observacional que incluyó a 15 niños con AIJ de entre 5 y 16 años. Se evaluó su rendimiento en el 1-STS. Resultados: se encontró una correlación positiva significativa entre el 1-STS y el test de la marcha de 6 minutos (r=0,56; p=0,03), como con el índice de capacidad funcional (CAPFUN) (r=0,54; p=0,03). No se observaron correlaciones significativas entre el Childhood Health Assessment Questionnaire (CHAQ) y el 1-STS (r=-0,21; p=0,44), tampoco con el Juvenile Arthritis Disease Activity Score (JADAS-10) (p=0,83). Conclusiones: el 1-STS parece prometedor para medir la capacidad aeróbico-funcional y la fuerza muscular de los miembros inferiores en niños con AIJ oligoarticular.

Abstract Introduction: children with juvenile idiopathic arthritis (JIA) experience periods of pain and immobility that affect their physical capacities. Objectives: to describe reference values for the 1-minute sit to stand test (1-STS) in children with JIA as an assessment of aerobic-functional capacity and lower limb muscle strength. Materials and methods: an observational study was conducted, including 15 children with JIA aged between 5 and 16 years. Their performance in the 1-STS was assessed. Results: a significant positive correlation was found between the 1-STS and the 6-Minute Walk Test (r=0,56; p=0,03), as well as with the Functional Capacity Index (CAPFUN) (r=0,54; p=0,03). No significant correlations were observed between the Childhood Health Assessment Questionnaire (CHAQ) and the 1-STS (r=-0,21; p=0,44), nor with the Juvenile Arthritis Disease Activity Score (JADAS-10) (p=0,83). Conclusions: the 1-STS appears promising for assessing aerobic-functional capacity and lower limb muscle strength in children with oligoarticular JIA.

Alternative method of photopolymerization of composite resin specimen for flexural strength test / Método alternativo de fotopolimerização de resinas compostas para teste de flexão

The flexural resistence is one of the most used test in researchs of mechanical characterization of resin composites for dental restoration. ISO 4049 photopolymerization technique performed static application stages of light tip. To polymerize the entire area of the specimen some areas must receive extra radiation. These areas with extra radiation are called overlap areas. In an attempt to remedy this problem, this research compared the ISO method with a new method using constant movement (CM) during photopolymerization. Twenty specimens (SPs) were produced with 25 x 2 x 2 mm, for each group, 10 specimens being polymerized by the static technique recommended by the ISO-4049 and 10 specimens polymerized by the CM technique for each LED curing light used. After Tukey's statistical analysis, it was found that there was no statistical difference in relation to flexural strength (FS) and for the flexural modulus of elasticity (EF). However, the standard deviation of both FS and EF were much lower in MC than in ISO. Therefore, the photopolymerization by CM of the samples for the flexural strength test proved to be a possible solution to the problem of overlap of the technique proposed by ISO.

O teste de flexão é um dos mais utilizados em pesquisa de caracterização mecânica de compósitos resinosos para restauração dentária. A técnica ISO 4049 é feita em etapas com aplicação estática da luz. Para que toda a área do corpo de prova receba esta radiação é preciso que outras áreas recebam radiação extra. Na tentativa de sanar tal problema, esta pesquisa comparou o método da ISO com um método que utiliza um movimento constante (MC) durante a fotopolimerização. Foram produzidos 20 corpos de provas (CPs) com 25 x 2 x 2 mm, para cada grupo, sendo 10 polimerizados pela técnica estática recomendada pela normativa ISO-4049 e 10 polimerizados pela técnica de movimentação contínua (MC) para cada fotopolimerizador LED utilizado. Após análise estatística de Tukey apurou-se que não houve diferença estatística em relação à resistência à flexão (RF) e para o módulo de elasticidade em flexão. Porém, percebe-se, que o desvio padrão tanto da RF quanto do EF foram bem menores em MC do que em ISO. Sendo assim, a fotopolimerização em movimentação constante (MC) das amostras para o teste de resistência à flexão se mostrou como uma possível solução para o problema de sobreposição na técnica proposta pela ISO.

Bonding strength of metal brackets to polished and glazed zirconia ceramics with 3 adhesives respectively / 实用口腔医学杂志

Objective:To investigate the effects of 3 adhesives on the bond force and durability of polished and glazed zirconia ceram-ics to orthodontic metal brackets respectively.Methods:Universal adhesives,Single Bond Universal(SBU)and Prime&Bond Universal(PBU)were respectively used to bond polished and glazed zirconia to metal braces of maxillary central incisors using TransbondTM MIP(TM)as the control.The shear bond strength(SBS),the fracture morphology and adhesive residual index(ARI)were examed after wa-ter bath or water bath-thermal cycling storage.Results:The adhesive(P＜0.001)and storage conditions(P＜0.001)significantly af-fected the shear bond strength of zirconia to brackets.There was no significant difference between the polished or glazed groups(P=0.09).SBU showed the stronger SBS and lower ABI,there were significant differences in ARI scores among the 3 cements(P＜0.001).Conclusion:SBU may have better bonding performance than PBU and TM in the orthodontic bonding of polished or glazed zir-conia surfaces to the zirconia ceramics.

Effects of fascia gun versus stretching on exercise-induced muscle fatigue / 中国组织工程研究

BACKGROUND:There are increasing scientific and technological ways to promote the recovery of muscle fatigue after sports,such as vibrating foam shaft,fascia gun relaxation,and ultra-low temperature cold therapy.Fascia gun relaxation has been widely used in practice,but there is still relatively little research on fascial guns. OBJECTIVE:To compare the effects of three relaxation methods(fascia gun,stretching,fascia gun+stretching)on muscle status and muscle strength during the recovery of exercise-induced muscle fatigue,and to provide scientific basis for the application of the three methods in practice. METHODS:Forty college students were randomly divided into control group(n=10),stretching group(n=10),fascia gun group(n=10),and fascia gun+stretching group(n=10).All subjects completed leg flexion and extension training at 60%1 RM,15 times per set,for 10 sets in total,to make exercise fatigue models.After modeling,the subjects were intervened with supine rest,static stretching,fascia gun relaxation,fascia gun+stretching relaxation respectively.Muscle status and muscle strength indexes were tested before exercise,immediately after exercise,immediately after relaxation,24 and 48 hours after exercise. RESULTS AND CONCLUSION:The muscle tension and dynamic hardness of the control group and the stretching group immediately after relaxation were significantly higher than those before training(P<0.01).However,there was no significant difference in the fascia gun group and fascia gun+stretching group before and after training(P>0.05).At 24 hours after training,the peak torque of the control group and fascia gun group was significantly lower than that before training(P<0.01),and there was no significant difference in the stretching group and fascia gun+stretching group before and 24 hours after training(P>0.05).To conclude,the fascia gun can immediately and effectively improve the muscle state of sports fatigue and stretching can promote the effective recovery of muscle strength within 24 hours after sports fatigue.Relaxation using fascia gun plus stretching can achieve the superposition of the two effects.

New trends and developments of functional training research in the field of health care / 中国组织工程研究

BACKGROUND:Functional training has been popular in recent years,but it is mainly applied in sports training field.There are still insufficient studies and applications in medical and health fields. OBJECTIVE:To provide a theoretical basis for relevant research in sports,medical and health fields,through a more comprehensive and in-depth exploration and analysis of the research hot spots,ideological trends,frontiers and development trends of international functional training in the field of medical and health care. METHODS:The 2 206 high-quality articles addressing health-related functional training during 2012-2022 were exported from the Web of Science Core Set Database as the object of analysis.Combined with research methods such as literature analysis,Citespace V analysis software was used for visual analysis of keywords,subject categories and highly cited literatures. RESULTS AND CONCLUSION:The number of articles published on functional training in the field of health is on the rise.There are more articles from the United States,with a larger impact.China also has a high volume of publications,but the impact and depth of research is lacking.Improving physical and mental health and cognitive ability of middle-aged and older people is the main focus,followed by preventing sports injuries and promoting recovery in athletes.In the future,more research will be conducted on teenagers,the disabled and other groups,and there will be a continued increase in injury prevention and recovery promotion for athletes.Chinese scholars have less research on the effects of functional training on the physical health of the general public,and more attention should be paid to improving the physical and mental health of the general public.

Rehabilitative efficacy of kinesio taping following anterior cruciate ligament reconstruction:a Meta-analysis / 中国组织工程研究

OBJECTIVE:Some studies have shown that kinesio taping has positive effects in elevating muscle strength,improving joint stability and reducing pain and oedema in patients after anterior cruciate ligament reconstruction.However,existing studies have divergent results on the clinical efficacy of kinesio taping.In this study,a meta-analysis was conducted to systematically evaluate the effect of kinesio taping in postoperative rehabilitation period following anterior cruciate ligament reconstruction. METHODS:Randomized controlled trials about the effects of kinesio taping on anterior cruciate ligament reconstruction were electronically searched in PubMed,Web of Science,Embase,The Cochrane Library,EBSCO,CNKI,WanFang,and VIP databases,from database inception to December 06,2022.The outcome measures included six continuous variables:quadriceps strength,hamstring strength,knee swelling,knee range of motion,Lysholm knee function score,and Visual Analogue Scale score.EndNote X9.1 was used to screen the literature.The Cochrane Risk Bias Assessment Tool and Jadad Scale were used to evaluate the quality of the included literature.RevMan 5.3 software was used for Meta-analysis. RESULTS:A total of 6 randomized controlled trials involving 252 patients undergoing anterior cruciate ligament reconstruction were finally included.There were 126 cases in control group and 126 in kinesio taping group.The results of Meta-analysis showed that compared with the control group,kinesio taping significantly improved hamstring strength[standardized mean difference(SMD)=0.68,95%confidence interval(CI):0.12 to 1.23,P=0.02)and reduced Visual Analogue Scale score[mean difference(MD)=-0.56,95%CI:-1.04 to-0.08,P=0.02).However,for quadriceps strength,knee swelling,knee range of motion,and Lysholm knee function score,kinesio taping did not show significant difference from the control group(P＞0.05). CONCLUSION:Kinesio taping may help to improve hamstring strength and reduce pain in patients after anterior cruciate ligament reconstruction.However,it cannot significantly improve quadriceps strength,knee swelling,knee range of motion,and functional scores.

Correlation of knee extensor muscle strength and spatiotemporal gait parameters with peak knee flexion/adduction moment in female patients with knee osteoarthritis / 中国组织工程研究

BACKGROUND:Previous studies have shown that knee joint moment changes in patients with knee osteoarthritis,but there are few reports on the correlation of moment changes with knee extensor muscle strength and gait spatiotemporal parameters. OBJECTIVE:To explore the correlation of knee extensor muscle strength and gait spatiotemporal parameters with peak knee flexion moment and knee adduction moment in female patients with knee osteoarthritis. METHODS:Twenty knee osteoarthritis female patients with single knee disease hospitalized in Guizhou Hospital,Beijing Jishuitan Hospital from February to August 2022 were selected as the knee osteoarthritis group,and an additional 20 healthy females without musculoskeletal disease were selected as the control group.The knee extensor force at 60(°)/s was measured with the Biodex isokinetic instrument.The gait spatiotemporal parameters and peak knee flexion moment and knee adduction moment were collected with the Italian BTS infrared motion capture system and force measuring platform.Pearson correlation analysis was used to explore the correlation of muscle strength and gait spatiotemporal parameters with peak knee adduction moment and knee flexion moment,and the variables significantly related to knee joint moment were further included in the multiple stepwise regression analysis. RESULTS AND CONCLUSION:(1)Compared with the control group,the knee osteoarthritis group had significantly lower knee extensor force,step speed,step frequency,step length,step width,peak knee adduction moment and knee flexion moment at 60(°)/s(P<0.05).(2)Pearson correlation analysis showed that the 60(°)/s centripetal extensor force,step speed,step frequency and step length were positively correlated with the peak knee flexion moment,and negatively correlated with the peak knee adduction moment,with a statistically significant difference(P<0.05).(3)The results of multiple stepwise regression showed that step speed and 60(°)/s knee extensor force were the strongest predictors of peak knee flexion moment,and the total R2 value of the two factors was 0.426,indicating that 42.6%of the total variance of this parameter could be explained.Step length and 60(°)/s centripetal extensor force were the strongest predictors of peak knee adduction moment.The total R2 value of the two factors was 0.602,indicating that 60.2%of the total variance of this parameter could be explained.(4)It is concluded that knee extensor strength,step speed and step length are the main variables affecting peak knee adduction moment and knee flexion moment.Therefore,these variables can be used for clinical gait monitoring and guidance to change knee joint load during knee osteoarthritis rehabilitation.

Changes in muscle strength and pain in patients receiving Jianpi Yiqi Huoxue Formula after total knee arthroplasty / 中国组织工程研究

BACKGROUND:Some patients still have unsatisfactory improvement of operative limb fatigue and pain after total knee arthroplasty.Clinical findings show that Jianpi Yiqi Huoxue Formula can promote recovery after total knee arthroplasty,but the specific efficacy remains to be studied. OBJECTIVE:To observe the effect of Jianpi Yiqi Huoxue Formula on the muscle strength and pain of the operated limb after the primary unilateral total knee arthroplasty. METHODS:A total of 74 patients undergoing primary unilateral total knee arthroplasty were randomly divided into a trial group and a control group with 37 patients in each group.All patients received the same prostheses and surgical methods during the operation.Patients in the control group were treated with routine analgesics,anticoagulant drugs and functional exercise after the operation.The trial group received Jianpi Yiqi Huoxue Formula after the treatment in the control group.Both groups were treated continuously and followed up for 1 month.The changes in isokinetic muscle strength(peak torque and total work amount of extensor and flexor),visual analog scale score and the hospital for special surgery score of the two groups were analyzed. RESULTS AND CONCLUSION:(1)The trial group had better improvement in peak torque and total work amount of extensor and flexor and the hospital for special surgery score than the control group 14 days and 1 month after surgery(P<0.05).(2)In contrast to the control group,the visual analog scale score of the trial group improved better at 7 and 14 days and 1 month after surgery(P<0.05).(3)It is indicated that Jianpi Yiqi Huoxue Formula can effectively improve the muscle strength of the operated limb,enhance the degree of postoperative joint pain,and promote functional rehabilitation after total knee arthroplasty.

Knee function recovery in patients with anterior cruciate ligament reconstruction after blood flow restriction training:a meta-analysis / 中国组织工程研究

OBJECTIVE:To systematically review the clinical effect of blood flow restriction training on rehabilitation after anterior cruciate ligament reconstruction to provide a reference for clinical practice. METHODS:Databases including CNKI,WanFang,PubMed,Web of Science and EBSCO were searched to collect randomized controlled trials of blood flow restriction training in the intervention of anterior cruciate ligament reconstruction from inception to August 10,2022.Outcomes included knee muscle strength,knee muscle mass,and knee function evaluation,all of which were continuous variables.Two reviewers independently screened the literature and extracted data.Cochrane bias risk assessment tool and Physiotherapy Evidence Database Scale were used to evaluate the bias risk of the included articles.Meta-analysis was then performed using RevMan 5.4 software. RESULTS:A total of 9 publications were included,including 226 subjects,114 in the trial group and 112 in the control group.Meta-analysis results showed that compared with conventional resistance training,the blood flow restriction training group could significantly improve knee muscle strength[SMD=0.54,95%CI(0.29,0.79),P＜0.01],muscle mass[SMD=0.26,95%CI(0.06,0.46),P=0.01]and knee joint function[SMD=1.17,95%CI(0.53,1.80),P＜0.01].Subgroup analysis showed that only when the intervention time was more than 4 weeks,there were significant improvements in knee joint muscle strength[SMD=0.68,95%CI(0.38,0.97),P＜0.01]and muscle mass[SMD=0.38,95%CI(0.09,0.68),P=0.01]. CONCLUSION:Current evidence shows that blood flow restriction training can improve muscle strength and knee function in patients with anterior cruciate ligament reconstruction and reduce muscle atrophy.It is recommended that the postoperative intervention time should be more than 4 weeks to achieve better muscle strength and muscle mass improvement.

Effect of blood flow restriction training on the fitness benefit of upper limb muscles / 中国组织工程研究

BACKGROUND:Blood flow restriction training has broad application prospects in improving limb muscle strength.It has ideal effects on the upper limbs is ideal,and the specific application scheme has high research value. OBJECTIVE:To explain the influence of blood flow restriction training on the fitness benefits of upper limb muscles and summarize the specific programs of blood flow restriction training for upper limb,attempting to give suggestions on application programs based on existing studies. METHODS:Literature on the application of upper limb blood flow restriction training were searched in CNKI,WanFang,VIP,CBM,PubMed,Embase,EBSCO,Cochrane Library and Web of Science databases.The search terms were"blood flow restriction,blood flow restriction training,pressure training,upper limb,upper arm,forearm,arm,forearm"in Chinese and"blood flow restriction training,blood flow restriction exercise,blood flow restriction therapy,BFR therapy,occlusion training,KAATSU training,BFRT,upper extremity,upper limb,arm,forearm"in English.The relevant articles on the application of blood flow restriction training in the upper limbs included in the database from database inception to December 2022 were selected and screened according to inclusion criteria and exclusion criteria. RESULTS AND CONCLUSION:Firstly,blood flow restriction training is mainly applied to healthy people,special athletes and people with upper limb injury.Secondly,the influence of blood flow restriction training on upper limb muscle fitness is mainly reflected in the increase of upper limb circumference,muscle strength,muscle endurance,muscle thickness,muscle cross-sectional area and explosive power of upper limb,followed by the cross migration phenomenon of the upper limbs.Thirdly,blood flow restriction training for the upper limbs mainly uses inflatable blood flow restriction devices:the cuff width was 3-5 cm,the pressure position was 1/3 of the upper arm,the limiting pressure was 40%-60%arterial occlusion pressure or 80-160 mmHg,the training load is 20%-30%1RM,the training volume is four sessions(30-15-15-15 times),the interval time was 30-60 seconds,and the training frequency was 2 or 3 times per week.

Prediction of osteoporotic vertebral compression fracture based on comprehensive index of lumbar vertebral bone strength / 中国组织工程研究

BACKGROUND:Osteoporotic vertebral compression fracture is a common fracture secondary to osteoporosis.At present,there is no effective prediction index and method for osteoporotic vertebral compression fracture. OBJECTIVE:To investigate the predictive effect of the comprehensive index of lumbar vertebral body bone strength on osteoporotic vertebral compression fracture. METHODS:233 patients with osteoporosis were divided into a fracture group and a non-fracture group according to whether a vertebral fracture occurred.The demography,body mass index,vertebral bone mineral density and other details were collected.Lateral X-ray films of the lumbar spine were photographed.The vertebral body width,vertebral body length,sacral slope,pelvic tilt,pelvic incidence,lumbar compressive strength index and the lumbar impact strength index were measured,calculated,and analyzed by univariate and multivariate,and the receiver operating characteristic curve was analyzed.The survival analysis was conducted according to the cut-off value. RESULTS AND CONCLUSION:(1)All patients were followed up for 2-4 years,with an average of 3.1 years.During the follow-up period,99 cases(38 cases of L1 vertebral body,61 cases of L2 vertebral body)had fractures(fracture group),and 134 cases(52 cases of L1 vertebral body,82 cases of L2 vertebral body)had no fractures(non-fracture group).Univariate analysis showed that there was no significant difference in age,sex,height,body mass,body mass index and fracture segment between the two groups(P>0.05).(2)Lumbar compressive strength index and lumbar impact strength index in the fracture group were lower than those in the non-fracture group(P<0.05).Pelvic incidence and pelvic tilt in the fracture group were higher than those in the non-fracture group(P<0.05).(3)Multivariate analysis showed that lumbar compressive strength index,lumbar impact strength index and pelvic tilt were risk factors for osteoporotic vertebral compression fractures(P<0.05).(4)Receiver operating characteristic curve analysis showed that the cutoff values of vertebral bone mineral density,lumbar compressive strength index,lumbar impact strength index,pelvic tilt and pelvic incidence were 0.913 5 g/cm2,1.932,0.903,21.5° and 55°,respectively;areas under the curve were 0.630,0.800,0.911,0.633 and 0.568,respectively.(5)According to the survival analysis(with osteoporotic vertebral compression fracture as the end point),the average survival time of the patients with lumbar impact strength index≥0.903 was significantly longer than that of the patients with lumbar impact strength index<0.903(P<0.05).(6)These findings conclude that the comprehensive index of lumbar vertebral body bone strength is more accurate than the bone mineral density of the vertebral body and spine-pelvis sagittal parameters in predicting osteoporotic vertebral compression fractures,which is helpful for early prevention and treatment of osteoporotic vertebral compression fractures.

Mechanism by which strength training improves bone injury in ovariectomized rats / 中国组织工程研究

BACKGROUND:Postmenopausal osteoporosis significantly increases the risk of fracture,which seriously affects the quality of life of patients.Exercise therapy is an important non-drug means and prevention and treatment strategy for patients with osteoporosis,in which strength training is the best mode,but its specific biological mechanism has not been determined. OBJECTIVE:To investigate the effects of strength training on bone morphology,materials and biomechanics in ovariectomized rats and to explore the mechanism of extracellular matrix remodeling. METHODS:Forty-eight female Sprague-Dawley rats were divided into sham operation group,sham operation exercise group,ovariectomized group and ovariectomized exercise group according to the random number table method.The menopausal animal model was established by bilateral ovariectomy in the ovariectomized group and ovariectomized exercise group,while sham operation was performed in the sham operation group and sham operation exercise group.Four weeks after operation,the sham operation exercise group and the ovariectomized exercise group underwent 12-week tail weight-bearing ladder training,and the sham operation group and the ovariectomized group were raised quietly in the cage.The bilateral femur and tibia were separated after training.The right tibia was used for dual-energy X-ray densitometry and biomechanical,biophysical and biochemical analyses,the left tibia was detected using micro-computed tomography for bone microstructural examination,the right femur was subjected to hematoxylin-eosin staining for histological observation,and the left femur was used for western blot and gelatin zymography detection of protein expression and enzyme activity of extracellular matrix metabolism-related factors,respectively. RESULTS AND CONCLUSION:Compared with the sham operation group,the maximal load and stiffness decreased(P＜0.05),bone density,bone mineral density,bone inorganic matter content,bone calcium content decreased(P＜0.05),bone water content increased(P＜0.05),trabecular bone volume fraction,trabecular connectivity density,and trabecular number decreased(P＜0.05),trabecular separation,structural model index increased(P＜0.05),bone adipocyte number and cross-sectional area increased(P＜0.05),matrix metalloproteinase-2 activity decreased(P＜0.05),and protein expression of tissue inhibitor of metalloproteinase-1 and osteoprotegerin increased(P＜0.05)in the ovariectomized group.Compared with the ovariectomized group,the maximal load,stiffness,fracture load and resilience increased(P＜0.05),bone mineral density,bone mineral content,bone mineral density,bone inorganic matter content,and bone calcium content increased(P＜0.05),bone water content decreased(P＜0.05),trabecular separation and bone marrow area decreased(P＜0.05),trabecular bone thickness,cortical bone volume fraction,cortical bone area fraction,cortical bone thickness,and cortical bone porosity increased(P＜0.05),bone adipocyte number and cross-sectional area reduced(P＜0.05),matrix metalloproteinase-2 activity increased(P＜0.05),and protein expression of tissue inhibitor of metalloproteinase-1,Runt-related transcription factor 2 and osteoprotegerin decreased(P＜0.05)in the ovariectomized exercise group.To conclude,strength training can protect against bone injury caused by estrogen deficiency,which is characterized by improvement of bone biomechanical properties,bone tissue composition and bone microstructure,and its mechanism is related to the regulation of extracellular matrix remodeling.