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ABSTRACT Introduction: The assessment of biomechanical changes related to the lower limbs is necessary in clinical practice to measure the potential risks of injury and the influences on existing dysfunction. Biomechanical changes related to previous ankle injuries are known to influence the performance of the entire lower limb. Objective: The aim of this study was to correlate muscle strength tests, performance tests and ankle stability with the Single Hop Test (SHT). Methods: 82 amateur runners were evaluated with isokinetic tests of quadriceps and hamstring muscle strength, as well as Y Balance Test (YBT), Weight-bearing Lung Test (WBLT), and the SHT. Results: The results showed there was a significant correlation between the SHT and the YBT in subjects with hamstring/quadriceps ratio (I/Q ratio) <0.55, and the length of the unilateral SHT with the peak torque of ipsilateral knee extensors. Conclusion: The study was successful in correlating the functional tests in question with the results obtained in isokinetic dynamometry. Level of Evidence V; Cross-Sectional Study.
RESUMEN Introducción: La evaluación de los cambios biomecánicos relacionados con las extremidades inferiores es necesaria en la práctica clínica para medir los riesgos potenciales de lesión y las influencias sobre la disfunción existente. Se sabe que los cambios biomecánicos relacionados con lesiones previas de tobillo influyen en el rendimiento de toda la extremidad inferior. Objetivo: Correlacionar las pruebas de fuerza muscular, las pruebas de rendimiento y la estabilidad del tobillo con la prueba de salto simple (Single Hop Test, SHT). Métodos: Se evaluó a 82 corredores aficionados con pruebas isocinéticas de fuerza muscular de cuádriceps e isquiotibiales, además de pruebas como Y Balance Test (YBT), Weight-bearing Lung Test (WBLT) y la prueba SHT. Resultados: Los resultados mostraron que existía una correlación significativa entre el SHT y el YBT en sujetos con ratio isquiotibiales/cuádriceps (ratio I/Q) <0,55, y la longitud del SHT unilateral con el par máximo de los extensores de la rodilla ipsilateral. Conclusión: El estudio logró correlacionar las pruebas funcionales en cuestión con los resultados obtenidos en la dinamometría isocinética. Nivel de Evidencia V; Estudio Transversal.
RESUMO Introdução: A avaliação de alterações biomecânicas relacionadas aos membros inferiores é necessária na prática clínica para mensurar os riscos potenciais de alguma lesão e as influencias sobre uma disfunção existente. As alterações biomecânicas relacionadas a lesões prévias de tornozelo são conhecidas pela influência na performance de todo o membro inferior. Objetivo: Correlacionar testes de força muscular, testes de performance e estabilidade do tornozelo com o teste de salto simples (Single Hop Test - SHT). Métodos: Foram avaliados 82 corredores amadores com testes isocinéticos de força muscular de quadríceps e isquiotibiais, além de testes Y Balance Test (YBT), Weight-bearing Lung Test (WBLT), e o SHT. Resultados: Os resultados demonstraram haver correlação significativa entre o SHT e o YBT nos indivíduos com relação Isquiotibiais/Quadríceps (relação I/Q) <0,55, e o comprimento do SHT unilateral com o pico de torque de extensores de joelho ipsilateral. Conclusão: O estudo foi bem sucedido em correlacionar os testes funcionais em questão com os resultados obtidos na dinamometria isocinética. Nível de Evidência V; Estudo Transversal.
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ABSTRACT Introduction: Events such as the Paralympic Games leave a series of legacies in the host societies. This is also applicable to the development of associated scientific knowledge, particularly in the field of sports biomechanics. Objective: The objective of this study is to investigate the Brazilian scientific production in the field of biomechanics in Paralympic sports during the cycle that preceded and followed the Rio 2016 Paralympic Games. Additionally, the study aims to provide insights for future research endeavors. Methods: The search was conducted on the Lattes Platform, utilizing the filters "Assunto" and "Doutores" and the keywords "Paralímpico" and "Paralympic." In total, 723 authors were identified who published articles related to the topic. Subsequently, the curricula were accessed, and the articles were sorted and identified, resulting in 37 articles that met all inclusion criteria. Results: The results indicate that: a) Brazil witnessed an increase in the number of publications after London 2012; b) The majority of these productions (87%) originate from Public Institutions; c) There was a greater participation of other regions of Brazil in the production of knowledge in the area after Rio 2016; d) Individual modalities such as powerlifting and athletics were the most researched, despite Brazil's reference status in some collective modalities; e) Women remain a minority, both as participants in research and as authors of publications; f) The productions demonstrate high levels of quality; g) The most commonly used research techniques in biomechanics were kinematics and dynamometry. Conclusion: The field of biomechanics in Paralympic sports has significantly benefited from the legacy generated by the Rio 2016 Paralympics. As future challenges for researchers, the following aspects stand out: maintaining the quality of productions, expanding studies to include collective modalities, increasing the participation of other federated entities in the production of knowledge in this field, promoting greater gender equity, and incorporating new research techniques in biomechanics. Level of Evidence II; Review Study.
RESUMEN Introducción: Eventos como los Juegos Paralímpicos dejan una serie de legados en las sociedades anfitrionas. Esto también es aplicable al desarrollo de conocimiento científico asociado, especialmente en el campo de la biomecánica deportiva. Objetivo: El objetivo de este estudio es investigar la producción científica brasileña en el campo de la biomecánica en deportes paralímpicos durante el ciclo que precedió y siguió a los Juegos Paralímpicos de Río 2016. Además, el estudio tiene como propósito brindar ideas para futuros esfuerzos de investigación. Métodos: La búsqueda se realizó en la Plataforma Lattes, utilizando los filtros " Assunto " y "Doutores" y las palabras clave "Paralímpico" y "Paralympic". En total, se identificaron 723 autores que publicaron artículos relacionados con el tema. Posteriormente, se accedió a los currículos y se clasificaron e identificaron los artículos, lo que resultó en 37 artículos que cumplieron con todos los criterios de inclusión. Resultados: Los resultados indican que: a) Brasil experimentó un aumento en el número de publicaciones después de Londres 2012; b) La mayoría de estas producciones (87%) provienen de Instituciones Públicas; c) Después de Río 2016, hubo una mayor participación de otras regiones de Brasil en la producción de conocimiento en el área; d) Las modalidades individuales, como levantamiento de pesas y atletismo, fueron las más investigadas, a pesar del estatus de referencia de Brasil en algunas modalidades colectivas; e) Las mujeres siguen siendo una minoría, tanto como participantes en investigaciones como autoras de publicaciones; f) Las producciones demuestran altos niveles de calidad; g) Las técnicas de investigación más utilizadas en biomecánica fueron la cinemática y la dinamometría. Conclusión: El campo de la biomecánica en deportes paralímpicos ha sido significativamente beneficiado por el legado generado por los Juegos Paralímpicos de Río 2016. Como desafíos futuros para los investigadores, se destacan los siguientes aspectos: mantener la calidad de las producciones, ampliar los estudios para incluir modalidades colectivas, aumentar la participación de otras entidades federadas en la producción del conocimiento en este campo, promover una mayor equidad de género e incorporar nuevas técnicas de investigación en biomecánica. Nivel de Evidencia II; Estudio de Revisión.
RESUMO Introdução: Eventos como os Jogos Paralímpicos deixam uma série de legados nas sociedades que as sediam. Não seria diferente quando se trata do desenvolvimento do conhecimento científico associado, em especial a biomecânica do esporte. Objetivo: Investigar a produção científica brasileira produzida em biomecânica no esporte paralímpico no ciclo que antecedeu e sucedeu os Jogos Paralímpicos Rio 2016, além de fornecer insights para novos estudos. Métodos: Foram realizadas buscas na Plataforma Lattes, sendo habilitados os filtros "Assunto" e "Doutores", com as palavras-chave "Paralímpico" e "Paralympic". Ao todo, foram encontrados 723 autores que publicaram artigo(s) relacionado(s) com o tema. Após acessar os currículos, os artigos foram triados e identificados, resultando em 37 artigos que preencheram todos os critérios de inclusão. Resultados: Os resultados mostram que a) Após Londres-2012, o Brasil tem aumentado o número de publicações; b) Grande parte das produções (87%) são oriundas de Instituições Públicas, c) Após Rio-2016 houve uma maior participação de outras regiões do Brasil na produção do conhecimento na área, d) Apesar do Brasil ser referência em algumas modalidades coletivas, modalidades individuais como o powerlifting e o atletismo, são as mais pesquisadas, e) Mulheres ainda são minoria, tanto como participantes das pesquisas quanto na autoria das publicações, f) As produções atingem elevados extratos de qualidade, g) As técnicas de pesquisa em biomecânica mais utilizadas foram a cinemática e dinamometria. Conclusão: A biomecânica no esporte paralímpico tem se valido do legado gerado pelas paralimpíadas Rio-2016. Como desafios futuros para os pesquisadores, destacam-se: manutenção da qualidade das produções, ampliação dos estudos para as modalidades coletivas, aumento da participação de outros entes federados na produção do conhecimento na área, promoção de uma maior equidade de gênero e incorporação de novas técnicas de pesquisa em biomecânica. Nível de Evidência II; Estudo de Revisão.
ABSTRACT
Abstract Since its introduction by Ilizarov, the distraction osteogenesis technique has been used to treat trauma-related conditions, infections, bone tumors, and congenital diseases, either as methods of bone transport or elongation. One of the major dilemmas for the orthopedic surgeon who performs osteogenic distraction is establishing a reproducible method of assessing the progression of the osteogenesis, enabling the early detection of regenerate failures,inorder toeffectively interfereduring treatment, andtodeterminetheappropriate time to remove the external fixator. Several quantitative monitoring methods to evaluate the structural recovery and biomechanical properties of the bone regenerate at different stages,aswell as the bone healing process, are under study. These methods can reveal data on bone metabolism, stiffness, bone mineral content, and bone mineral density. The present review comprehensively summarizes the most recent techniques to assess bone healing during osteogenic distraction, including conventional radiography and pixel values in digital radiology, ultrasonography, bone densitometry and scintigraphy, quantitative computed tomography, biomechanical evaluation, biochemical markers, and mathematical models. We believe it is crucial to know the different methods currently available, and we understand that using several monitoring methods simultaneously can be an ideal solution, pointing to a future direction in the follow-up of osteogenic distraction.
Resumo Desde que foi descrita por Ilizarov, a técnica de osteogênese por distração tem sido utilizada para o tratamento de diversas condições relacionadas ao trauma, infecções, tumores ósseos edoenças congênitas, naforma detransporteou alongamento ósseo. Um dos dilemas mais comuns do cirurgião ortopédico que realiza distração osteogênica é o estabelecimentodeum método reprodutível deverificaçãoda progressão da osteogênese, que permita a detecção precoce de falhas no regenerado, para que se possa interferir de formaeficazduranteotratamento,bemcomodeterminarotempoapropriadoderemoção dofixadorexterno.Recentemente,váriosmétodosdemonitoramentoquantitativo,comos quais se poderia avaliar a recuperação da estrutura e as propriedades biomecânicas do regenerado ósseoemdiferentes estágios, alémdoprocessodecicatrização óssea, têm sido amplamente investigados. Por esses métodos, pode-se saber o conteúdo mineral ósseo, a densidade mineral óssea, a rigidez e o metabolismo ósseo. Nesta revisão, resumimos de forma abrangente as técnicas mais recentes para avaliar a cicatrização óssea durante a distração osteogênica, entre elas, métodos como aradiografia convencional e os valores de pixels em radiologia digital, a ultrassonografia, a densitometria e a cintilografia ósseas, a tomografia computadorizada quantitativa, a avaliação biomecânica, os marcadores bioquímicos e os modelos matemáticos. Consideramos fundamental o conhecimento dos diversos métodos à disposição atualmente e entendemos que a utilização de vários métodos de monitoramento simultaneamente possa ser uma solução ideal, que aponte para uma direção futura no seguimento da distração osteogênica.
Subject(s)
Biomechanical Phenomena , Evaluation Studies as TopicABSTRACT
Abstract Objective: Rupture of the anterior cruciate ligament (ACL) is one of the most common injuries in athletes and is often associated with damage to anterolateral structures. This combination of injuries presents itself clinically as a high-grade pivot shift test. The hypothesis of this study is that patients with ACL deficiency and high-grade pivot shift test should have an increased internal knee rotation. Methods: Twenty-two patients were tested. After effective spinal anesthesia, two tests were performed with the patient in supine position. First, the bilateral pivot shift test was performed manually, and its grade was recorded. Then, with the knee flexed to 90 degrees, the examiner drew the projection of the foot in a neutral position and in maximum internal rotation, and the angle of internal rotation was measured from the axes built between the central point of the heel and the hallux. Results: In the ACL-deficient knee, it was observed that there is a statistically significant average internal rotation (IR) delta of 10.5 degrees between the groups when not adjusted for age, and 10.6 degrees when adjusted for age. Conclusions: Knees with ACL deficiency and with pivot shift test grade I do not show increased internal rotation in relation to knees with intact ACL. Knees with ACL deficiency and with pivot shift test grades II and III show increased internal rotation in comparison to healthy knees.
Resumo Objetivo: A ruptura do ligamento cruzado anterior (LCA) é uma das lesões mais comuns em atletas e está frequentemente associada a danos nas estruturas anterolaterais. Esta combinação de lesões apresenta-se clinicamente como um teste de pivot shift de alto grau. A hipótese deste estudo é que pacientes com deficiência de LCA e teste de pivot shift de alto grau tenham aumento da rotação interna (RI) do joelho. Métodos: Vinte e dois pacientes foram testados. Após raquianestesia efetiva, foram realizados dois testes com o paciente em posição supina. Primeiro, o teste de pivot shift bilateral foi realizado manualmente e seu grau foi registrado. Em seguida, com o joelho flexionado a 90 graus, o examinador traçou a projeção do pé em posição neutra e em RI máxima e mediu o ângulo de RI a partir dos eixos construídos entre o ponto central do calcanhar e o hálux. Resultados: Joelhos com deficiência de LCA apresentam delta da RI média estatisticamente significativo de 10,5 graus entre os grupos sem ajuste de idade e de 10,6 graus com ajuste de idade. Conclusões: Joelhos com deficiência do LCA e teste de pivot shift de grau I não apresentam aumento da RI em relação aos joelhos com LCA íntegro. Joelhos com deficiência do LCA e teste de pivot shift de graus II e III apresentam RI em comparação aos joelhos saudáveis.
Subject(s)
Humans , Male , Female , Biomechanical Phenomena , Anterior Cruciate Ligament/surgery , Joint InstabilityABSTRACT
Objective:To delineate the morphological features of pedicle-facet joints in lumbar spondylolysis patients, correlating these with spinopelvic parameters to explore their mechanisms and clinical implications.Methods:This study enrolled 121 patients with L 5 spondylolysis (IS group), 108 with L 4, 5 degenerative spondylolisthesis (DS group), and 100 with normal L 4, 5 but L 5S 1 lumbar disc herniation (NL group), who underwent radiography and multislice spiral CT from May 2020 to January 2023. Parameters including vertebral slip percentage (SP) and spinopelvic alignments, such as sacral slope and lumbar lordosis, were quantified using standing lateral lumbar radiographs. Morphological parameters of the L 4 and L 5 facet joints were measured on 3D reconstructed lumbar CT images, including the facet joint angle (FJA), pedicle-facet joint angle (PFA), facet joint osteoarthritis (OA), and facet joint tropism (FT). Results:The analysis revealed significant variances in SS and LL among the groups ( F=21.910, P<0.001; F=22.439, P<0.001). The IS group exhibited the highest SS and LL, followed by the DS and NL groups. Morphological assessments showed the largest L 4 FJA in the IS group, with progressive decreases in the DS and NL groups ( F=344.791, P<0.001). Conversely, L 4 PFA was greatest in the DS group ( F=193.725, P<0.001). Notably, L 4 OA was markedly more severe in the DS group compared to IS and NL groups ( H=467.925, P<0.001), with no significant disparity between IS and NL groups ( P>0.05). Correlation analyses within each cohort highlighted a negative association of sacral slope and lumbar lordosis with facet joint angles, yet a positive correlation with pedicle-facet joint angles both with statistical significance ( P<0.05). Furthermore, L 4 facet joint angles were consistently smaller than those at L 5, and L 4 pedicle-facet joint angles were larger than L 5 ( P<0.05). Osteoarthritis at L 5 was more pronounced in the IS group compared to L 4 ( Z=7.043, P<0.001), a trend inversely observed in the DS group ( Z=11.868, P<0.001), while the NL group showed no significant osteoarthritic variance between levels ( Z=0.556, P=0.578). Conclusion:Patients with lumbar spondylolysis demonstrate elevated sacral slope and lumbar lordosis, indicative of increased localized biomechanical stress in the lumbar spine. These alterations in the morphology of the pedicle-facet joints highlight the distinctive structural adaptations and potential strain distributions within this cohort.
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ABSTRACT BACKGROUND: Current research supports the fact that prophylactic ankle taping (AT) is effective in preventing ankle injuries in amateur and elite sports athletes. OBJECTIVE: This study aimed to investigate the effect of AT on balance, knee valgus during drop jump and single-leg countermovement jump (SL-CMJ) landings, and ankle range of motion (ROM) restriction in healthy participants. DESIGN AND SETTING: A cross-sectional observational study was conducted at the Universidad Europea de Madrid, Madrid, Spain. METHODS: Participants: Thirty-nine healthy individuals participated in this study and performed the movements under two conditions (with and without tape). Outcome measurements: ankle ROM, balance, SL-CMJ height, flight time, ground time, and knee valgus. Before any intervention, a random process was developed with a 1:1 allocation ratio, and the participants were assigned to groups A (tape-no tape) and B (no tape-tape). RESULTS: Significant differences between tape and no-tape moments were observed for drop jump knee valgus flexion (P = 0.007), with an increase in knee valgus in participants with ankle taping. Similarly, the Y-balance testshowed a significant decrease in all variables (P = 0.001 and), ankle dorsiflexion (P = 0.001) in participants with ankle taping. CONCLUSIONS: AT is effective for immediate ankle ROM restriction. However, an increase in knee valgus during drop jump task and a decrease in lower limb balance were observed during drop jump task. Based on these results, it can be concluded that AT application in healthy individuals should not be recommended as it results in increase in injury risk factors.
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Introducción. La población de personas mayores (PM) en Chile presenta un incremento sostenido con importantes tasas de fragilidad y riesgo de caídas (RC). El desempeño de marcha permite valorarlo mediante parámetros mecánicos y fisiológicos. Nos preguntamos, ¿cuáles podrían ser los más relevantes para estimar RC en condiciones de marcha confortable (MC) y máxima (MM)? Objetivo. Identificar los principales parámetros de marcha que podrían explicar RC en PM autovalentes de la comunidad. Métodos. Estudio observacional y transversal en el cual participaron 53 PM autovalentes de la comuna de Talca, Chile (edad 71±7años; IMC 29,1±3,4 kg/m2). Se solicitó a los participantes la ejecución de MC (n=53) y posteriormente MM (n=36). Ambas modalidades fueron desarrolladas en un circuito elíptico de 40m durante 3min. El RC se categorizó como: "sin riesgo", "riesgo dinámico" según prueba timed up and go (TUG) positiva, "riesgo estático" según estación unipodal (EUP) positiva y "riesgo mixto" con ambas pruebas positivas. Para la visualización de la variación gráfica en el morfoespacio de los individuos según RC, se realizó un análisis de componentes principales (ACP) mediante el Programa RStudio, utilizando 6 variables cinemáticas: i) velocidad promedio de marcha (VPM), ii) cadencia, iii) máximo despeje del pie (MDP), iv) coeficiente de variación (%CV) del MDP, v) longitud de zancada (LZ) y vi) %CV de la LZ. Además de 2 variables fisiológicas: i) % frecuencia cardiaca de reserva utilizada (%FCRu) y ii) el índice de costo fisiológico según la relación entre FC y VM (latidos/metros). Resultados. Para MC las dimensiones del ACP explican el 56% de la variabilidad de los datos, siendo los indicadores de seguridad de RC la VM, cadencia, LZ y MDP. La variabilidad de marcha explica RC mixto y el ICF junto al %FCRu se asocian a RC dinámico. En condiciones de MM, el ACP explica 60% de la variabilidad de datos, donde las PM sin RC se asocian con VM, LZ y MDP. Por su parte, la variabilidad del MDP se vincula con RC dinámico y las variables fisiológicas con el RC mixto. Conclusiones. Los parámetros de marcha que mejor explican una marcha segura y eficiente son cinemáticos de la fase de balanceo, mientras que la variabilidad y el costo fisiológico se asocian como indicadores de RC dinámico y mixto.
Background. Introduction: The elderly population (EP) in Chile is experiencing a sustained increase with significant rates of frailty and risk of falls (RF). Gait performance can be assessed using mechanical and physiological parameters. We wonder, which ones could be the most relevant to estimate RF in self-selected walking speed (SSWS) and maximum walking speed (MWS) conditions? Objective. Identify the main gait parameters that could explain RF in self-sufficient elderly individuals from the community. Methods. This observational and cross-sectional study included 53 self-sufficient elderly individuals from the commune of Talca, Chile (age 71±7 years; BMI 29.1±3.4 kg/m2). Participants were asked to perform SSWS (n=53) and subsequently MWS (n=36). Both modalities were conducted on a 40m elliptical circuit for 3 minutes. RF was categorized as: "no risk," "dynamic risk" based on a positive timed up and go test, "static risk" based on a positive one-legged stance test, and "mixed risk" with both tests positive. To visualize the graphical variation in the morphospace of individuals according to RF, a principal component analysis (PCA) was conducted using RStudio, utilizing 6 kinematic variables: i) walking speed (WS), ii) cadence, iii) maximum foot clearance (MFC), iv) coefficient of variation (%CV) of MFC, v) stride length (SL), and vi) %CV of SL. In addition to 2 physiological variables: i) % of reserve heart rate used (%RHRu) and ii) the physiological cost index based on the relationship between heart rate and WS (heartbeats/meters). Results. For SSWS, the PCA dimensions explained 56% of the data variability, with gait safety indicators such as WS, cadence, SL, and MFC explaining RF. Gait variability explains mixed RF, while the physiological cost index and %RHRu are associated with dynamic RF. In MWS conditions, PCA explains 60% of the data variability, where the elderly persons without RF are associated with WS, SL, and MFC. On the other hand, MFC variability is related to dynamic RF, and physiological variables are associated with mixed RF. Conclusions. The gait parameters that best explain safe and efficient walking are kinematic parameters of the swing phase, while variability and physiological cost are indicators of dynamic and mixed RF.
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Abstract Jump height continues to be widely used to predict power in humans. Individual progress is often monitored on the basis of estimated power, but prediction equations are based on group data. The objective of the study was to show that vertical jump performance (vJP) and mechanical power are poorly associated, particularly within individuals. Two experiments are presented. First, 52 physically active male college students performed five maximal vertical jumps each. Second, three young male participants performed 50 maximal jumps each. Participants rested for 1 minute between jumps. vJP was calculated from kinematic data as peak body center of mass (BCOM) minus standing BCOM; peak power (PEAKPWR) was calculated from the vertical ground reaction force registered by a force plate, and average power (MEANPWR) during propulsion from the change in potential energy of BCOM. Regression analyses were performed using standardized vJP scores as the predictor variable and standardized power scores as the resulting variables, expecting an identity function of y = x (intercept = 0, slope = 1) and R2 = 1. In experiment 1, the model for zPEAKPWR R2 = 0.9707 (p < 0.0001) but slope (0.3452) ≠ 1 (p < 0.0001). The model for zMEANPWR R2 = 0.9239 (p < 0.0001); nevertheless, slope (0.4257) ≠ 1 (p < 0.0001). In experiment 2, all individual models for zPEAKPWR and zMEANPWR resulted in poor associations (R2 ≤ 0.21) and slopes ≠ 1 (p≤0.001). In conclusion, regression analysis for individuals, and even for groups, confirms that vJP is a poor predictor of mechanical power.
Resumo A altura do salto ainda é amplamente usada para prever a potência em humanos. O progresso individual é frequentemente monitorado usando a estimativa de potência, mas as equações de previsão são baseadas em dados de grupo. O objetivo do estudo é demonstrar que a altura do salto vertical (ASv) e a potência mecânica têm uma correlação débil, principalmente em um mesmo indivíduo. São apresentados dois experimentos: primeiro, 52 estudantes universitários fisicamente ativos realizaram cinco saltos verticais máximos cada um; segundo, três participantes do sexo masculino realizaram 50 saltos máximos cada um. Os participantes descansaram por 1 minuto entre os saltos. A ASv foi calculada a partir de dados cinemáticos como a posição mais alta do centro de massa corporal (CMC) menos o CMC em pé; a potência de pico (PEAKPWR) foi calculada a partir da força de reação vertical registrada por uma plataforma de força e a potência média (MEANPWR) durante a propulsão a partir da mudança na energia potencial do CMC. As análises de regressão foram realizadas usando os escores da ASv padronizados como variável preditora e os escores de potência padronizados como variáveis de resultado, com a expectativa de obter uma função de identidade y = x (interceptação = 0, inclinação = 1) e R2 = 1. No experimento 1, o modelo para zPEAKPWR produziu R2 = 0,9707(p < 0,0001), mas a inclinação (0,3452) ≠ 1 (p = 8,7x10-15). O modelo para zMEANPWR apresentou R2 = 0,9239 (p < 0,0001); no entanto, a inclinação (0,4257) ≠ 1 (p = 1,15x10-5). No experimento 2, todos os modelos individuais para zPEAKPWR e zMEANPWR apresentaram associações débeis (R2 ≤ 0,21) e inclinações ≠ 1(p ≤ 0,001). Em conclusão, a análise de regressão para indivíduos e até mesmo para grupos confirma que a ASv é um indicador débil da potência mecânica.
Resumen La altura del salto se sigue usando ampliamente para predecir la potencia en seres humanos. El progreso individual, a menudo, se monitorea usando una estimación de la potencia, pero las ecuaciones de predicción se basan en datos grupales. El estudio pretende demostrar que la altura del salto vertical (ASv) y la potencia mecánica tienen una pobre correlación, particularmente en un mismo individuo. Se presentan dos experimentos; primero, 52 estudiantes universitarios físicamente activos ejecutaron cinco saltos verticales máximos cada uno; segundo, tres participantes masculinos ejecutaron 50 saltos máximos cada uno. Los participantes descansaron 1 minuto entre saltos. ASv se calculó a partir de los datos cinemáticos como posición más alta del centro de masa corporal (CDM) menos CDM de pie; la potencia pico (PEAKPWR) se calculó a partir de la fuerza vertical de reacción registrada por una plataforma de fuerza y la potencia promedio (MEANPWR) durante la propulsión a partir del cambio en la energía potencial del CDM. Se realizaron análisis de regresión usando puntajes estandarizados de ASv como la variable predictora y puntajes estandarizados de potencia como las variables resultantes, con la expectativa de obtener una función de identidad y = x (intercepto = 0, pendiente = 1) y R2 = 1. En el experimento 1, el modelo para zPEAKPWR arrojó R2 = 0.9707 (p <.0001) pero la pendiente (0.3452) ≠ 1 (p = 8.7x10-15). El modelo para zMEANPWR dio R2 = 0.9239 (p < .0001); sin embargo, la pendiente (0.4257) ≠ 1 (p = 1.15x10-5). En el experimento 2, todos los modelos individuales para zPEAKPWR y zMEANPWR arrojaron asociaciones débiles (R2 ≤ 0.21) y pendientes ≠ 1 (p ≤ .001). En conclusión, el análisis de regresión para individuos y aún para grupos confirma que la ASv es un pobre predictor de la potencia mecánica.
Subject(s)
SportsABSTRACT
Abstract Objectives Although osteonecrosis of the femoral head is a prevalent condition, its effects on gait parameters have not been thoroughly studied and are not well-established in the current literature. The primary aim of the present study is to describe gait in patients with a diagnosis of osteonecrosis. Methods This is a cross-sectional study. Nine patients diagnosed with osteonecrosis of the femoral head who were regularly followed-up at an outpatient clinic were selected for the present study and underwent gait analysis using Vicon Motion Capture Systems. Spatiotemporal data was obtained, and joint angles were calculated using an Euler angle coordinate system. Distal coordinate systems were used to calculate joint momentsand forceplatestoobtaingroundreactionforces. Results Patients with osteonecrosis presented with slower velocity (0.54 m/s ± 0.19) and smaller cadence (83.01 steps/min ± 13.23) than healthy patients. The pelvic obliquity range of motion was of 10.12° ± 3.03 and rotation was of 18.23° ± 9.17. The mean hip flexion was of 9.48° ± 3.40. Ground reaction forces showed reduced braking and propelling forces. Joint moments were reduced for flexion and adduction (0.42 Nm/kg ± 0.2 and 0.30 Nm/kg ± 0.11, respectively) but the abduction moment was increased (0.42 Nm/kg ± 0.18). Conclusions The present study showed that osteonecrosis of the femoral head presents compensatory gait mechanisms, with increased pelvic motion and decreased knee flexion to protect the hip joint. Decreased moments for hip flexion and adduction were also identified and muscle weakness for those groups may be correlated to the disease.
Resumo Objetivos Embora a osteonecrose da cabeça do fêmur seja uma lesão prevalente, seus efeitos sobre os parâmetros da marcha não foram minuciosamente estudados e não estão bem estabelecidos na literatura atual. O objetivo principal do presente estudo é descrever a marcha em pacientes com osteonecrose. Métodos Trata-se de um estudo transversal. Nove pacientes com diagnóstico de osteonecrose da cabeça do fêmur, sob acompanhamento regular em ambulatório, foram selecionados para o presente estudo e submetidos à análise da marcha com Vicon Motion Capture Systems. Os dados espaciais e temporais foram obtidos e os ângulos articulares foram calculados com o sistema de coordenadas angulares de Euler. Sistemas de coordenadas distais e plataformas de força foram utilizados para o cálculo de momentos articulares e de forças de reação ao solo, respectivamente. Resultados Os pacientes com osteonecrose apresentaram menor velocidade (0,54 m/s ± 0,19) e menor cadência (83,01 passos/minuto ± 13,23) do que pacientes saudáveis. As amplitudes de movimento de obliquidade e rotação pélvica foram de 10,12°± 3,03 e 18,23° ± 9,17, respectivamente. A média de flexão do quadril foi de 9,48° ± 3,40. O estudo das forças de reação ao solo revelou redução das forças de frenagem e propulsão. Os momentos articulares de flexão e adução caíram (0,42 Nm/kg ± 0,2 e 0,30 Nm/kg ± 0,11), mas o momento de abdução aumentou (0,42 Nm/kg ± 0,18). Conclusões O presente estudo mostrou que a osteonecrose da cabeça do fêmur é associada a mecanismos compensatórios da marcha, com aumento da movimentação pélvica e diminuição da flexão do joelho para proteção da articulação do quadril. A redução dos momentos de flexão e adução do quadril também foi identificada e a fraqueza destes grupos musculares pode estar correlacionada à doença.
Subject(s)
Humans , Biomechanical Phenomena , Arthroplasty, Replacement, Hip , Femur Head Necrosis , Gait AnalysisABSTRACT
Abstract Objective This study assessed differences between fully- and partially-threaded screws in the initial interfragmentary compression strength. Our hypothesis was that there would be an increased loss in initial compression strength with the partially-threaded screw. Methods A 45-degree oblique fracture line was created in artificial bone samples. The first group (FULL, n = 6) was fixed using a 3.5-mm fully-threaded lag screw, while the second group (PARTIAL, n = 6) used a 3.5-mm partially-threaded lag screw. Torsional stiffness for both rotational directions were evaluated. The groups were compared based on biomechanical parameters: angle-moment-stiffness, time-moment-stiffness, maximal torsional moment (failure load), and calibrated compression force based on pressure sensor measurement. Results After loss of one PARTIAL sample, no statistically significant differences in calibrated compression force measurement were observed between both groups: [median (interquartile range)] FULL: 112.6 (10.5) N versus PARTIAL: 106.9 (7.1) N, Mann-Whitney U-test: p = 0.8). In addition, after exclusion of 3 samples for mechanical testing (FULL n = 5, PARTIAL n = 4), no statistically significant differences were observed between FULL and PARTIAL constructs in angle-moment-stiffness, time-moment-stiffness, nor maximum torsional moment (failure load). Conclusion There is no apparent difference in the initial compression strength (compression force or construct stiffness or failure load) achieved using either fully-or partially-threaded screws in this biomechanical model in high-density artificial bone. Fully-threaded screws could, therefore, be more useful in diaphyseal fracture treatment. Further research on the impact in softer osteoporotic, or metaphyseal bone models, and to evaluate the clinical significance is required.
Resumo Objetivo Este estudo avaliou diferenças entre parafusos com rosca total ou parcial na resistência à compressão interfragmentar inicial. Nossa hipótese era de que haveria maior perda de resistência à compressão inicial com o parafuso de rosca parcial. Métodos Uma linha de fratura oblíqua de 45 graus foi criada em amostras de osso artificial. O primeiro grupo (TOTAL, n = 6) foi fixado com um parafuso de 3,5 mm de rosca total, enquanto o segundo grupo (PARCIAL, n = 6) usou um parafuso de 3,5 mm de rosca parcial. Avaliamos a rigidez à torção em ambas as direções de rotação. Os grupos foram comparados com base nos seguintes parâmetros biomecânicos: momento de rigidez-ângulo, momento de rigidez-tempo, momento de torção máxima (carga de falha) e força de compressão calibrada com base na medida do sensor de pressão. Resultados Depois da perda de uma amostra PARCIAL, não foram observadas diferenças estatisticamente significativas na força de compressão calibrada entre os 2 grupos [mediana (intervalo interquartil)]: TOTAL: 112,6 (10,5) N e PARCIAL: 106,9 (7,1) N, com p = 0,8 segundo o teste U de Mann-Whitney). Além disso, após a exclusão de 3 amostras para testes mecânicos (TOTAL, n = 5, PARCIAL, n = 4), não foram observadas diferenças estatisticamente significativas entre os construtos TOTAL e PARCIAL quanto ao momento de rigidez-ângulo, momento de rigidez-tempo ou momento de torção máxima (carga de falha). Conclusão Não há diferença aparente na força de compressão inicial (força de compressão ou rigidez do construto ou carga de falha) com o uso de parafusos de rosca total ou parcial neste modelo biomecânico em osso artificial de alta densidade. Parafusos de rosca total podem, portanto, ser mais úteis no tratamento de fraturas diafisárias. Mais pesquisas são necessárias sobre o impacto em modelos ósseos osteoporóticos ou metafisários de menor densidade e avaliação do significado clínico.
Subject(s)
Humans , Biomechanical Phenomena , Bone Cements , Bone Screws , Fractures, Bone/surgeryABSTRACT
Abstract The failure of ligament reconstruction has different risk factors, among which we can highlight the period before its incorporation, which is a mechanically vulnerable period. Loss of resistance over time is a characteristic of living tissues. Dissection with bone insertions of the cruciate ligaments of animal models is not described; however, it is essential for monoaxial assays to extract information from tests such as relaxation. The present work describes the dissection used for the generation of a test body for the performance of nondestructive tests to evaluate the mechanical behavior. We performed dissection of four porcino knee ligaments, proposing a dissection technique for the cruciate ligaments with bone inserts for comparison with collateral ligaments. The ligaments were submitted to relaxation tests and had strain gauges placed during the tests. The results showed viscoelastic behavior, validated by strain gauges and with a loss over time; with some ligaments presenting with losses of up to 20%, a factor to be considered in future studies. The present work dissected the four main ligaments of the knee demonstrating the posterior approach that allows maintaining their bone insertions and described the fixation for the monotonic uniaxial trials, besides being able to extract the viscoelastic behavior of the four ligaments of the knee, within the physiological limits of the knee.
Resumo A falha da reconstrução ligamentar tem diferentes fatores de risco, dentre os quais podemos destacar o período antes da sua incorporação, o qual configura um período mecânico vulnerável. A perda de resistência ao longo do tempo é uma característica dos tecidos vivos. A dissecção com as inserções ósseas dos ligamentos cruzados de modelos animais não é descrita; todavia, para os ensaios monoaxiais, é fundamental extrair as informações de ensaios como os de relaxação. O presente trabalho realiza a descrição da dissecção utilizada para a geração de corpo de prova para a realização de ensaios não destrutivos para avaliar o comportamento mecânico. Realizamos dissecção de quatro ligamentos de joelho porcino, propondo uma técnica de dissecção para os ligamentos cruzados com as inserções ósseas para comparação com os colaterais. Os ligamentos foram submetidos a testes de relaxação e foram colocadas strain gauges durante os testes. Os resultados mostraram comportamento viscoelástico, validado pelas strain gauges e com uma perda ao longo do tempo, sendo que, em alguns ligamentos, as perdas chegaram a até 20%, fator este a ser considerado em trabalhos futuros. O presente trabalho dissecou os quatro principais ligamentos do joelho, demonstrando a abordagem posterior que permite manter as suas inserções ósseas e descrevendo a fixação para os ensaios uniaxiais monotônicos, além de ter conseguido extrair o comportamento viscoelástico dos quatro ligamentos do joelho dentro dos limites fisiológicos do joelho.
Subject(s)
Animals , Tensile Strength , Biomechanical Phenomena , Dissection , Knee JointABSTRACT
Introducción. La distocia de hombros es una complicación del parto vaginal que se produce por dificultad en el parto de los hombros fetales. Puede desencadenarse en forma impredecible e imprevista, por lo que debería ser considerada como riesgo potencial de todo nacimiento. La mayoría de las recomendaciones sobre las maniobras de resolución de distocia de hombros lo hacen desde la posición de litotomía y sin considerar los movimientos intrínsecos de la pelvis durante el parto. Objetivos. Analizar las maniobras de resolución de distocia de hombros a partir del conocimiento de la biomecánica de la pelvis y su relación con los hombros fetales, teniendo en cuenta las diferentes posiciones de parto. Métodos. Revisión bibliográfica no sistematizada. Resultados. Ante la distocia del hombro anterior, si la gestante se encuentra en litotomía podría recomendarse la maniobra de McRoberts con presión suprapúbica seguida de la extracción del brazo posterior. Si la gestante se encuentra en posición vertical, se sugiere pasar a posición de cuatro apoyos y una variante original resultado del análisis de los movimientos de la pelvis llamada 'cuatro apoyos en asimetría'. Esta puede ser realizada desde cualquier posición, no es invasiva y requiere un mínimo de entrenamiento. Conclusiones. La resolución de distocia de hombros no posee un único algoritmo; dependerá del tipo de distocia, la posición de la gestante, el contexto y la mayor o menor habilidad de una maniobra sobre otra. La postura de Gaskin y cuatro apoyos en asimetría debería ser tenida en cuenta antes de realizar maniobras internas para la resolución de la distocia de hombros.
Introduction: Shoulder dystocia is a complication of vaginal delivery caused by a difficulty in delivering the fetal shoulders. It can be triggered in an unpredictable and unplanned manner, so it should be considered as a potential risk for every vaginal birth. Most of the recommendations on shoulder dystocia resolution maneuvers are made from the lithotomy position and without considering the intrinsic movements of the pelvis during labor. Objectives : To analyze the maneuvers for resolving shoulder dystocia based on knowledge of the biomechanics of the pelvis and its relationship with the fetal shoulders, considering the different birthing positions. Methods: Non-systematized bibliographic review. Results : In the case of anterior shoulder dystocia, the McRoberts maneuver with suprapubic pressure followed by extraction of the posterior arm could be recommended for a birthing woman in lithotomy position. If the birthing woman is in an upright position, it is suggested to move to the four-support position and an original variant resulting from the analysis of the biomechanics of the pelvis called 'four-lying in asymmetry'. These maneuvers are non-invasive techniques, require minimal training and resources, and can be performed from any childbirth position. Conclusions : The resolution of shoulder dystocia does not have a single algorithm; it will depend on the type of dystocia, the position of the birthing woman, the context, and the greater or lesser ability of one maneuver over another. Gaskin maneuver and four supports in asymmetry should be considered before performing internal maneuvers for the resolution of shoulder dystocia.
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ABSTRACT Introduction: With the gradual improvement of the theoretical system of sports biomechanics and the high requirements of Taekwondo development, the scientific research of Taekwondo is no longer restricted to a monothematic perspective; sports biomechanics is a combination of the complex forms of movement and body changes in the sport, a discipline that combines the principles of mechanics and biology for research. This discipline, allied to the study of sport, contributes to the correct understanding, training, and mastery of movement techniques. Objective: Apply a technical analysis of the taekwondo kick through a sports biomechanics approach. Methods: Using a three-dimensional kinematic motion capture system, volunteers of 58kg, 68kg, 80kg, and three other weight classes, in a total of 30 athletes, participated in this research. The movements included technical kicks and the collection of motion trajectories when hitting the target. Results: There were significant differences in the angle, angular velocity, torque, action time, displacement, and velocity of the lower limb joints of the three weight classes (P<0.05). Conclusion: The higher the athlete's weight, the lower the body agility; although the striking distance is relatively long, the impact on movement speed is relatively minor. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.
RESUMO Introdução: Com a melhoria gradual do sistema teórico da biomecânica esportiva e os altos requisitos do desenvolvimento do Taekwondo, a pesquisa científica do Taekwondo deixou de restringir-se a uma perspectiva monotemática, a biomecânica esportiva é uma combinação das complexas formas de movimento e alterações corporais no esporte, disciplina que combina os princípios da mecânica e da biologia para a pesquisa. Essa disciplina, aliada ao estudo esportivo, contribui para a correta compreensão, formação e domínio das técnicas de movimento. Objetivo: Aplicação a análise técnica do chute no taekwondo pela abordagem biomecânica esportiva. Métodos: Utilizando um sistema tridimensional de captura de movimento cinemático, voluntários de 58 kg, 68kg, 80 kg e outras três classes de peso, num total de 30 atletas, participaram dessa pesquisa. Os movimentos incluíram chutes técnicos e a coleta das trajetórias de movimento ao acertar o alvo. Resultados: Houveram diferenças significativas no ângulo, velocidade angular, torque, tempo de ação, deslocamento e velocidade das articulações dos membros inferiores das três classes de peso (P<0,05). Conclusão: Quanto maior o peso do atleta, menor a agilidade do corpo, embora a distância de batida seja relativamente longa, o impacto na velocidade do movimento é relativamente menor. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.
RESUMEN Introducción: Con la mejora gradual del sistema teórico de la biomecánica deportiva y las altas exigencias del desarrollo del taekwondo, la investigación científica del taekwondo ya no se limita a una perspectiva monotemática, la biomecánica deportiva es una combinación de las complejas formas de movimiento y cambios corporales en el deporte, una disciplina que combina los principios de la mecánica y la biología para la investigación. Esta disciplina, aliada al estudio deportivo, contribuye a la correcta comprensión, entrenamiento y dominio de las técnicas de movimiento. Objetivo: Aplicar el análisis técnico de la patada de taekwondo mediante el enfoque biomecánico deportivo. Métodos: Utilizando un sistema de captura de movimiento cinemático tridimensional, participaron en esta investigación voluntarios de 58kg, 68kg, 80kg y otras tres clases de peso, en un total de 30 atletas. Los movimientos incluían patadas técnicas y la recogida de las trayectorias de los movimientos al golpear el objetivo. Resultados: Hubo diferencias significativas en el ángulo, la velocidad angular, el par, el tiempo de acción, el desplazamiento y la velocidad de las articulaciones de los miembros inferiores de las tres clases de peso (P<0,05). Conclusión: Cuanto mayor es el peso del atleta, menor es la agilidad corporal, aunque la distancia de golpeo es relativamente larga, el impacto en la velocidad de movimiento es relativamente menor. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.
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ABSTRACT Introduction: The shot accuracy and standardization in basketball games are closely related to the quality of the team's scoring. The percentage of throws is fundamental to know if the basketing movement can be correctly detected and judged. In traditional basketball, players' skills are composed of specific movements. With the gradual development of these technical movements, coaches should pay more attention to each athlete so that their technical problems can be identified and worked on early. Objective: This article discusses how basketball players move, catch the ball on the court, and execute the shot to the basket. Methods: We randomly and voluntarily selected 90 basketball players by sampling. The independent variables, biomarkers, and kinetic patterns were properly cataloged and processed. The main test items included body, lower limb, and groin circumference. Finally, mathematical statistics were used to analyze the correlation of each index. The relationship between basketball players' movement posture and basic offensive techniques was analyzed. Results: In basketball, basic attack techniques in multifactorial training remarkably influences their score. The role of score recovery in basketball is significant. Conclusion: The quality of basketing action is directly related to the technical level of offensive basketball. A variety of ball training can improve the skill level of the basketball player. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.
RESUMO Introdução: A precisão de lance e a padronização nos jogos de basquete estão intimamente relacionadas à qualidade da pontuação do time. A porcentagem de lances é fundamental para saber se o movimento de encestamento pode ser corretamente detectado e julgado. No basquete tradicional, as habilidades dos jogadores são compostas por movimentos específicos e, com o desenvolvimento gradual desses movimentos técnicos, os treinadores devem prestar maior atenção a cada atleta para que seus problemas técnicos sejam identificados e trabalhados precocemente. Objetivo: Este artigo discute como os jogadores de basquete se movem, pegam a bola no confronto e executam o lance para a cesta. Métodos: Selecionou-se aleatória e voluntariamente 90 jogadores de basquete por amostragem. As variáveis independentes, biomarcadores e padrões cinéticos foram devidamente catalogados e processados. Os principais itens de teste incluem perímetro corporal, perímetro de membros inferiores e virilha. Por fim, utilizou-se o método de estatística matemática para analisar a correlação de cada índice. Paralelamente, a relação entre a postura de movimento dos jogadores de basquete e as técnicas ofensivas básicas foram analisadas. Resultados: O treinamento multifatorial na técnica de ataque básico do basquete tem uma influência notável em sua pontuação de ataque. O papel da recuperação de pontuações no basquete é significativo. Conclusão: A qualidade da ação de encestamento está diretamente relacionada ao nível técnico do basquete ofensivo. Uma variedade de treinamento com bola pode melhorar o nível de habilidade do jogador de basquete. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.
RESUMEN Introducción: El acierto en el tiro y la normalización en los partidos de baloncesto están estrechamente relacionados con la calidad de la puntuación del equipo. El porcentaje de lanzamientos es fundamental para saber si se puede detectar y juzgar correctamente el movimiento de enceste. En el baloncesto tradicional, las habilidades de los jugadores están compuestas por movimientos específicos y, con el desarrollo gradual de estos movimientos técnicos, los entrenadores deben prestar más atención a cada deportista para que sus problemas técnicos sean identificados y trabajados a tiempo. Objetivo: Este artículo analiza cómo se mueven los jugadores de baloncesto, cómo cogen el balón en el enfrentamiento y cómo ejecutan el tiro a canasta. Métodos: Se seleccionaron 90 jugadores de baloncesto de forma aleatoria y voluntaria por muestreo. Las variables independientes, los biomarcadores y los patrones cinéticos fueron debidamente catalogados y procesados. Los principales elementos de la prueba son la circunferencia corporal, la circunferencia de las extremidades inferiores y la circunferencia de la ingle. Por último, se utilizó el método de estadística matemática para analizar la correlación de cada índice. Paralelamente, se analizó la relación entre la postura de movimiento de los jugadores de baloncesto y las técnicas ofensivas básicas. Resultados: El entrenamiento multifactorial en la técnica de ataque básica del baloncesto tiene una notable influencia en su puntuación de ataque. El papel de la recuperación del marcador en el baloncesto es importante. Conclusión: La calidad de la acción de encestar está directamente relacionada con el nivel técnico del baloncesto ofensivo. Una variedad de entrenamiento con balón puede mejorar el nivel de habilidad del jugador de baloncesto. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.
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Antecedentes: El handball es un deporte "overhead" que expone al hombro a demandas elevadas de carga durante la práctica, lo que puede llevar a esta articulación a sufrir adaptaciones específicas. La comprensión de estas adaptaciones es importante y puede ayudar a los clínicos a crear protocolos de prevención y a desarrollar programas de condicionamiento y rehabilitación para esta población. Objetivos: Generar un perfil descriptivo de:1) movimiento escapular durante la elevación y descenso de la extremidad superior en el plano escapular, 2) distancia acromiohumeral y 3) rango de movimiento y fuerza rotacional glenohumeral en deportistas femeninas de handball de élite. Métodos: Se realizo un estudio transversal observacional y descriptivo en 23 jugadoras (Edad = 22±4.3 años; Años de practica 9.7±3.5) de handball de élite, libres de dolor. Se valoró el movimiento escapular bilateral durante la elevación y el descenso del brazo, la distancia acromiohumeral durante la abducción activa y pasiva, y el rango de movimiento articular y la fuerza rotacional GH en rotación interna y externa. Se describen estas variables, comparándolas entre ambos brazos, y entre los grupos formados en función del déficit de rotación interna GH. Resultados: No se detectaron diferencias significativas en el movimiento escapular 3D ni en la distancia acromiohumeral entre los brazos. Se observó una disminución del rango de rotación interna (Diferencia Media (DM)= -11.09°; Intervalo Confianza 95% (IC)= -17.70,-4.47) y un incremento del rango de rotación externa (DM= 12.82°; IC= 6.07°,19.58°) en el hombro dominante. El torque rotacional GH en rotación externa fue mayor (DM= 0.36 Nm/kg; IC=-0.008 Nm/kg, -0.81Nm/kg) en el hombro dominante. Las participantes con déficit de rotación interna mostraron mayores rangos de rotación superior y tilt posterior escapular durante la elevación, mayor distancia acromiohumeral en reposo y mayor disminución de esta durante la elevación de la extremidad Conclusión: Los resultados sugieren que no existen diferencias en el movimiento escapular durante la elevación y descenso de la extremidad superior, ni en la distancia acromiohumeral en las diferentes posiciones de elevación GH activa y pasiva entre el brazo dominante y no dominante de las deportistas femeninas de handball de élite. Los hallazgos indican que el brazo lanzador de estas deportistas presenta diferencias en el rango rotacional y en la fuerza, que podrían representar un factor de riesgo lesional, siendo detectables en el ambiente clínico. Las deportistas que presentan GIRD, muestran mayor movimiento escapular 3D durante la elevación, mayor DAH en reposo y mayor disminución de esta durante la elevación de la ES
Background: Handball is an overhead sport that exposes the shoulder to high demands of load during the practice, which may lead this joint to sport-specific adaptions. Understanding these adaptions is important and may help clinicians to create preventive protocols and further develop conditioning and rehabilitation program to this population. Objectives: To generate a descriptive profile of:1) scapular motion during upper extremity raising and lowering along the scapular plane, 2) acromiohumeral distance, and 3) GH rotational range of motion and rotational strength in elite female handball athletes. Methods: This is observational and descriptive cross-sectional study. Twenty-three (22±4.3 years and 9.7±3.5 years of practice) pain free elite female handball players were assessed. Outcome measures included bilateral 3D scapular movement during raising and lowering of the arm, acromiohumeral distance during passive and active abduction, GH range of motion of internal and external rotation, and strength of the internal and external rotators. These variables were described by comparing them between both arms, and among the groups according to the GH internal rotation deficit. Results: No significant differences were detected in 3D scapular motion or acromiohumeral distance between the arms. A decrease in internal rotation range of motion (Mean Difference (MD) =-11.09°;95% Confidence Interval (CI)= -17.70°, -4.47°) and an increase in external rotation range of motion (MD= 12.82°; CI=6.07°, 19.58°) and in GH rotational torque in external rotation (MD=0.36 Nm/kg; CI=-0.008Nm/kg, -0.81Nm/kg) were observed in the dominant shoulder. Participants with internal rotation deficit showed greater ranges of superior rotation and scapular posterior tilt during raising, greater acromiohumeral distance at rest and greater decrease of this during limb elevation. Conclusion: The findings suggest there are no differences in in the scapular movement during upper extremity raising and lowering along the scapular plane, nor in the acromiohumeral distance during passive and active GH between the dominant and non-dominant arm of elite female handball athletes. The findings indicate that there are differences in rotational range of motion and strength between both arms, which could represent an injury risk factor, being detectable in the clinical sports environment. Participants with internal rotation deficit showed greater scapular 3D movement, greater DAH at rest and greater decrease of it during arm elevation
Subject(s)
Humans , Female , Scapula/injuries , Team Sports , Movement Disorders , Epidemiology, Descriptive , Cross-Sectional Studies , Risk Factors , Academic DissertationABSTRACT
Acute Achilles tendon rupture (AATR) is one of the most common sport injuries in clinical practice, which is usually treated surgically or non-surgically. Regardless of treatment choice, early weight bearing should be encouraged to promote tendon healing. After ruptured Achilles tendon is healed, permanent defects in the biomechanical function of the patients′ affected lower limbs are found and performance in running, jumping, and competitive sports is affected, which may be due to a decrease in the flexion strength of the ankle as a result of tendon elongation following the repair of an Achilles tendon. The methods for evaluating tendon elongation can be divided into indirect measurement and direct measurement. Achilles tendon resting angle (ATRA) is the most commonly used and reliable indirect measurement index, while ultrasound and MRI are commonly used for direct measurement. However, there is no recommended "gold standard" at present. Among the potential influencing factors of tendon elongation, the choice of surgical or non-surgical treatment, different tendon suturing methods and start time of weight bearing have attracted attention and are still controversial. The authors reviewed the research progress of tendon elongation's effects on lower limb biomechanics, evaluation of tendon elongation, and factors affecting tendon elongation so as to provide reference for clinical diagnosis and treatment as well as related researches.
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The spinal cord, encompassed by the dura mater, arachnoid membrane, pia mater, dentate ligament, and cerebrospinal fluid, consists of both gray and white matter. This study delves into the biomechanical properties of the spinal cord and its adjacent structures, revealing its nature as a nonlinear viscoelastic medium. Notably, both gray and white matter exhibit hyperelastic characteristics, displaying distinct mechanical responses during uniaxial tensile and mechanical compression experiments. Furthermore, it is noteworthy that the human spinal cord does not maintain uniform length, while the dura mater exhibits pronounced anisotropy, with its elastic modulus gradually decreasing from the cervical to the lumbar region. While research on the biomechanical behavior of the arachnoid membrane is limited, its potential to enhance predictive accuracy in spinal finite element models is evident. Unfortunately, there is a lack of documented studies exploring the biomechanics of the human pia mater. Crucially, the spinal cord is immersed in cerebrospinal fluid, which acts as a cushion against spinal cord vibrations. Therefore, the significance of cerebrospinal fluid should not be underestimated in examining the biomechanical dynamics of the spinal cord, as changes in cerebrospinal fluid pressure correspondingly affect spinal cord stress levels. Additionally, the strength of the dentate ligament decreases progressively from superior to inferior regions. Due to the inherent softness of spinal cord tissue, it often undergoes complex mechanical alterations such as stretching, compression, and torsion when subjected to injury. Various measurement techniques, including magnetic resonance elastography (MRE), atomic force microscopy, microindentation, and myelography, are employed for spinal cord assessment. MRE, in particular, offers distinct advantages in scrutinizing spinal cord morphology. Accurately quantifying the mechanical parameters of spinal cord deformation injuries remains a challenge. Advanced imaging technologies are employed to monitor the dynamic pathological transformations of the spinal cord, providing valuable insights for clinical prevention and treatment strategies. Finite element analysis plays a pivotal role in the study of spinal cord injuries. However, existing modeling methodologies often oversimplify the spinal cord, portraying it as a homogenous material. Further experimental validation is required to confirm its accuracy. An exhaustive exploration of spinal cord biomechanics and measurement techniques is essential to gain a deeper understanding of the mechanisms underlying spinal cord injuries. This knowledge can serve as crucial theoretical guidance and support for the treatment and prevention of such injuries.
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Objective:To investigate the feasibility of establishing a canine model of lumbar intervertebral disc degeneration through the application of cumulative axial load and a six-phase combined motion on the vertical sitting dog's lumbar spine.Methods:Twenty adult female grass dogs, each weighing 10.0±0.5 kg, were randomly divided into two groups, with 10 dogs in each group. In the model group, dogs were secured to an exercise machine in a vertical position, and six phases of lumbar spine movement (flexion and extension, left and right lateral flexion, left and right rotation, 45° each) were combined with a specific number of cycles under continuous axial load (245 N). In the control group, dogs were secured to the exercise machine in a vertical position without any intervention. Radiographic examinations were performed before and after 20,000, 50,000, 100,000, and 150,000 compound exercises in the model group. The disc height index (DHI) was measured through lateral X-ray, and MRI T2-mapping was used for quantitative analysis of intervertebral disc degeneration. When intervertebral disc degeneration was evident on MRI T2-weighted imaging (modified Pfirrmann system > Grade V), the combined motion was halted. Micro-CT quantitative analysis of bone mineral density (BMD) in the upper and lower endplates, trabecular bone structure, and histological staining (HE staining, "O" staining, Sirius red staining) were employed to verify and assess the degree of intervertebral disc degeneration.Results:After 50,000 compound exercises, mild degeneration of the intervertebral discs at L 6-7 and L 7S 1 was observed on T2-weighted imaging. With the accumulation of exercise load, the degree of degeneration progressively increased, reaching a moderate degree of degeneration after 100,000 composite exercises, and DHI began to decrease. Mild degeneration was also observed in the upper L 5-6 intervertebral disc. When the cumulative exercise volume reached 150,000 repetitions, the height of intervertebral spaces in the L 5-6, L 6-7, and L 7S 1 segments further decreased, and the intervertebral discs exhibited severe degeneration (improved Pfirrmann grading system Grades IV-VI). The upper L 4-5 intervertebral discs also displayed mild degeneration. Histological scores were as follows: L 5-6 (8.2±0.8), L 6-7 (9.5±0.7), and L 7S 1 (10.3±0.5), indicating a degree of degeneration in the order of L 5-6<L 6-7<L 7S 1. HE and safranine "O" staining confirmed the significant collapse of the intervertebral spaces in the L 5-6, L 6-7, and L 7S 1 segments, characterized by severe shrinkage of the nucleus pulposus tissue, a disordered internal structure, and nearly absent vacuolar-like nucleus pulposus cells. Sirius red staining revealed pronounced folds, disordered arrangement, and multiple fractures in the fibers of the anterior and posterior rings of the intervertebral disc. The posterior ring of the disc exhibited more pronounced changes than the anterior ring, and the thickness of the bone endplate and bone trabecular density became thinner and less dense. Micro-CT quantitative analysis further confirmed that the BMD and number of trabeculae in the upper and lower endplates of the L 5-6, L 6-7, and L 7S 1 segments were significantly lower than those in the control group and other segments of the model group, while the trabecular separation was significantly higher than that in the control group and other segments of the model group. Conclusion:The utilization of the "Lumbar Composite Exercise Machine" can effectively replicate the biomechanical and kinematic characteristics of human lumbar intervertebral discs. Cumulative axial load and six-phase composite exercise can induce varying degrees of chronic degeneration in canine lumbar intervertebral discs, which is related to the exercise load, particularly in the L 5-6, L 6-7, and L 7S 1 segments.
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OBJECTIVE@#To investigate the biomechanical characteristics of retinaculum in the treatment of femoral neck fractures.@*METHODS@#The CT data of a 75-year-old female volunteer was processed by software to construct an intact femur model and femoral neck fracture model fixed with three cannulated screws, which were divided into models with retinaculum or not. The Von-Mises stress distribution and displacement were compared to analyze the stability differences between the different models to study the mechanical characteristics of the retinaculum in the treatment of femoral neck fractures.@*RESULTS@#In the intact femur, the most obvious displacement appeared in the weight-bearing area of the femoral head, with retinaculum 0.381 37 mm, and without retinaculum 0.381 68 mm. The most concentrated part of the Von-Mises stress distribution was located in the medial and inferior part of the femoral neck, with retinaculum 11.80 MPa, without retinaculum 11.91 MPa. In the femoral neck fracture fixed with three cannulated screws model, the most obvious position of displacement also appeared in the weight-bearing area of the femoral head, with retinaculum 0.457 27 mm, without retinaculum 0.458 63 mm. The most concentrated part of the Von-Mises located at the medical and inferior part of the femoral neck, with retinaculum 59.22 MPa, without retinaculum 59.14 MPa. For the cannulated screws, the Von-Mises force peaks all appeared in the posterior and superior screw, with retinaculum 107.48 MPa, without retinaculum 110.84 MPa. Among the three screws, the Von-Mises stress of the anterior-superior screw was the smallest, which was 67.88 MPa vs 68.76 MPa in the retinaculum and non-retinaculum groups, respectively.@*CONCLUSION@#The complete retinaculum has little effect on the stability of intact femur and femoral neck fractures with anatomical reduction after internal fixation, and cannot effectively improve the stability of the fracture end after the fracture.
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Female , Humans , Aged , Finite Element Analysis , Femoral Neck Fractures/surgery , Fracture Fixation, Internal , Bone Screws , Femur Neck , Biomechanical PhenomenaABSTRACT
The maxillary bone restriction can limit the implants position to support a full-arch prosthesis. Objective:Therefore, this study evaluated the biomechanical behavior of a full-arch prosthesis supported by six implants in different configurations: group A (implants inserted in the region of canines, first premolars and second molars), group B (implants inserted in the region of first premolar, first molar and second molar) and group C (implants in second premolar, first premolar and second molar). Material and Methods: The models were analyzed by the finite element method validated by strain gauge. Three types of loads were applied: in the central incisors, first premolars and second molars, obtaining results of von-Mises stress peaks and microstrain. All registered results reported higher stress concentration in the prosthesis of all groups, with group C presenting higher values in all structures when compared to A and B groups. The highest mean microstrain was also observed in group C (288.8 ± 225.2 µÎµ/µÎµ), however, there was no statistically significant difference between the evaluated groups. In both groups, regardless of the magnitude and direction of the load, the maximum von-Mises stresses recorded for implants and prosthesis displacements were lower in group A. Conclusion: It was concluded that an equidistant distribution of implants favors biomechanical behavior of full-arch prostheses supported by implants; and the placement of posterior implants seems to be a viable alternative to rehabilitate totally edentulous individuals. (AU)
A limitação óssea maxilar totais pode limitar o posicionamento dos implantes para suportar uma prótese de arco total. Objetivo: Sendo assim, este estudo avaliou o comportamento biomecânico de uma prótese de arco total suportada por seis implantes em diferentes configurações: grupo A (implantes inseridos na região de caninos, primeiros pré-molares e segundos molares), grupo B (implantes inseridos na região de primeiro pré-molar, primeiro molar e segundo molar) e grupo C (implantes em segundo pré-molar, primeiro pré-molar e segundo molar). Materiais e métodos: Os modelos foram analisados pelo método de elementos finitos validados por extensometria. Foram aplicados três tipos de cargas: nos incisivos centrais, primeiros pré-molares e nos segundos molares, obtendo resultados de picos de tensão de von-Mises e microdeformação. Todos os resultados registrados mostraram maior concentração de tensão na prótese de todos os grupos, sendo que o grupo C apresentou maiores valores em todas as estruturas quando comparado com os grupos A e B. A maior média de microdeformação também foi observada no grupo C (288,8 ± 225,2 µÎµ/µÎµ), no entanto, não houve diferença estatisticamente significativa entre os grupos avaliados. Em todos os grupos, independentemente da magnitude e direção da carga, as tensões máximas de von-Mises registradas para os implantes e deslocamentos de próteses foram menores no grupo A. Conclusão: Concluiu-se que a distribuição de implantes de forma equidistante favorece o desempenho biomecânico das próteses de arco total suportada por implantes; e o posicionamento de implantes posteriores parece ser uma alternativa viável para reabilitar indivíduos densdentados totais. (AU)