Effect of growth hormone (GH) and resistance training on the collagen properties of femoral bone tissue / Efecto de la hormona de crecimiento (HC) y el entrenamiento de fuerza en las propiedades colágenas del tejido óseo femoral

The indiscriminate use of anabolic steroids in gyms has been growing in a generalized way, among which, the most common is growth hormone (GH). In the short term GH may potentiate muscle growth, especially when taken in combination with resistance training. However, the effects of this hormone are not yet fully understood in the literature, especially in relation to collagen properties. The objective of this study was to evaluate the effect of the application of growth hormone (GH) and resistance training (RT) on the collagen properties of femoral bone tissue using Raman Spectroscopy. In this study 40 male rats were randomly distributed into four groups (n=10): control (C), control and GH application (GH), resistance training (T), and resistance training and GH application (GHT). The training consisted of four series of 10 water jumps, performed three times a week, with an overload corresponding to 50 % of body weight and duration of four weeks. GH was applied at a dosage of 0.2 IU/Kg (0.067 mg/kg) to each animal, three times a week, every other day. The animals were euthanized and the right femurs were collected for analysis of bone structure. Raman spectroscopy (RS) was used to observe the following compounds from their respective bands: type I collagen (662 cm-1), amide III (1243 cm-1), proteins including type I collagen (1278 cm-1), woven collagen (1322 cm-1), association of collagen, phospholipids, nucleic acid, and phosphate (1330 cm-1), and collagen and protein deformation (1448 cm-1). The results demonstrated an increase in the collagen properties in all analyzed variables, however, the T group presented a statistically significant difference (p<0.05). It is possible to conclude that isolated physical training was shown to be more efficient than when combined with the application of GH to increase the collagen properties of the femoral bone tissue.

El uso indiscriminado de anabolizantes en los gimnasios ha aumentado de forma generalizada, entre éstos la hormona de crecimiento (HC) es una de las más utilizadas, y a corto plazo puede potencializar el crecimiento muscular, principalmente cuando es realizado en combinación con el entrenamiento de fuerza. Sin embargo, los efectos de esta hormona aún no están totalmente esclarecidos en la literatura, especialmente en relación a las propiedades colágenas. El objetivo del estudio fue evaluar el efecto de la aplicación del HC y entrenamiento de fuerza (E) en las propiedades colágenas del tejido óseo femoral a partir de la utilización de la espectroscopía Raman. Se usaron 40 ratas Wistar distribuidos en cuatro grupos (n=10): control (C), control y aplicación del HC (HCC), entrenamiento de fuerza (E) y entrenamiento de fuerza y aplicación del HC (THC). El entrenamiento fue compuesto por cuatro series de 10 saltos acuáticos, realizados tres veces por semana, con sobrecarga correspondiente a 50 % del peso corporal y duración de cuatro semanas. El HC fue aplicado en una dosificación de 0,2 UI/Kg (0,067 mg/kg) en cada animal, tres veces por semana, en días no consecutivos. Los animales fueran eutanasiados y se retiró el fémur derecho para realización del análisis de la estructura ósea. La espectroscopía Raman (ER) fue utilizada para observar los siguientes compuestos a partir de las respectivas bandas: colágeno tipo I (662 cm-1), amida III (1243 cm1), proteínas, incluido colágeno tipo I (1278 cm-1), colágeno retorcido (1322 cm-1), asociación de colágeno, fosfolípidos, ácidos nucleicos y fosfato (1330 cm-1), deformación de colágeno y proteína (1448 cm-1). Hubo aumento en las propiedades colágenas en todas las variables analizadas, sin embargo, solamente el grupo E demostró una diferencia estadísticamente significativa (p<0,05). En conclusión, para el aumento de las propiedades colágenas del tejido óseo femoral, el entrenamiento físico aislado es más eficiente que el entrenamiento combinado con el uso de HC.

Finite element analysis of the femur of Japanese quail ( Coturnix coturnix japonica ) / Análisis por elementos finitos del fémur de codorniz japonesa ( Coturnix coturnix japonica )

The biomechanical performance of limb bones is useful to reflect an animal's adaptation to external loads and behaviors. In this study, we used the finite element method to simulate the load acting on the intact femur of the Japanese quails (Coturnix coturnix japonica) in the context of terrestrial locomotion and take-off for flight, in order to explore the functional significance of the femoral form and limb postures. It is shown that the distribution of stress was similar in all cases, furthermore, the lower 2/3 of the dorsal and ventral region of the femur suffered higher stress, and the junction between the distal diaphysis and the medial condyle was the most vulnerable area. The stress reaches its highest value under the condition of about 90-100 degrees of loading angle; when this angle is larger than 110 degrees, the femur will be relatively safe. These findings suggested that quail femur is more suitable to terrestrial locomotion than take-off. This kind of work will contribute to revealing the locomotor behavior of fossil taxa.

El rendimiento biomecánico de los huesos de los miembros es útil para reflejar la adaptación de un animal a las cargas y comportamientos externos. En este estudio, utilizamos el método de elementos finitos para simular la carga que actúa sobre el fémur intacto de las codornices japonesas (Coturnix coturnix japonica) en el contexto de la locomoción terrestre y el despegue para el vuelo, con el objetivo de explorar la importancia funcional de la forma femoral y posición de los miembros. En el estudio, la distribución del estrés fue similar en todos los casos; además, los 2/3 inferiores de la región dorsal y ventral del fémur sufrieron un mayor estrés, y la unión entre la diáfisis distal y el cóndilo medial fue el área más vulnerable. La tensión alcanza su mayor valor bajo la condición de, aproximadamente, 90-100 grados de ángulo de carga; cuando este ángulo es mayor a 110 grados, el fémur esta relativamente seguro. Estos hallazgos sugieren que el fémur de codorniz es más adecuado para la locomoción terrestre que para el despegue. Este tipo de trabajo contribuirá a revelar el comportamiento locomotor de los taxones fósiles.

Low-level laser therapy associated to a resistance training protocol on bone tissue in diabetic rats

ABSTRACT Objective The present study aimed to evaluate the in vivo response of a resistance training and low-level laser therapy (LLLT) on tibias and femurs of rats with diabetes mellitus (DM). Materials and methods Forty male Wistar rats were randomly distributed into four experimental groups: control group (CG), diabetic group (DG), diabetic trained group (TG) and diabetic trained and laser irradiated group (TLG). DM was induced by streptozotocin (STZ) and after two weeks laser and resistance training started, performed for 24 sessions, during eight weeks. At the end of the experiment, animals were euthanized and tibias and femurs were removed for analysis. Histological, histomorphometrical, immunohistochemistry and mechanical analyses were performed. Results Trained groups, with or without laser irradiation, showed increased cortical area, bone density and biomechanical properties. The immunohistochemical analysis revealed that TG and TLG demonstrated an increased RUNX2 expression. RANK-L immunoexpression was similar for all experimental groups. Conclusion In conclusion, it can be suggested that the resistance exercise program stimulated bone metabolism, culminating in increased cortical tibial area, bone mineral content, bone mineral density and biomechanical properties. Furthermore, the association of physical exercises and LLLT produced higher values for bone mineral content and stiffness. Consequently, these data highlight the potential of physical exercise in the management of bone loss due to DM and the possible extra osteogenic stimulus offered by lasertherapy. Further long-term studies should be carried out to provide additional information.

High-impact exercise in rats prior to and during suspension can prevent bone loss

High-impact exercise has been considered an important method for treating bone loss in osteopenic experimental models. In this study, we investigated the effects of osteopenia caused by inactivity in femora and tibiae of rats subjected to jump training using the rat tail suspension model. Eight-week-old female Wistar rats were divided into five groups (n=10 each group): jump training for 2 weeks before suspension and training during 3 weeks of suspension; jump training for 2 weeks before suspension; jump training only during suspension; suspension without any training; and a control group. The exercise protocol consisted of 20 jumps/day, 5 days/week, with a jump height of 40 cm. The bone mineral density of the femora and tibiae was measured by double energy X-ray absorptiometry and the same bones were evaluated by mechanical tests. Bone microarchitecture was evaluated by scanning electron microscopy. One-way ANOVA was used to compare groups. Significance was determined as P<0.05. Regarding bone mineral density, mechanical properties and bone microarchitecture, the beneficial effects were greater in the bones of animals subjected to pre-suspension training and subsequently to training during suspension, compared with the bones of animals subjected to pre-suspension training or to training during suspension. Our results indicate that a period of high impact exercise prior to tail suspension in rats can prevent the installation of osteopenia if there is also training during the tail suspension.

Radiographic study on the anatomical characteristics of the proximal femur in Brazilian adults / Estudo radiográfico dos aspectos anatômicos do fêmur proximal dos adultos brasileiros

To ascertain the geometry of the femur in the Brazilian population by means of a radiographic study and to correlate the values with regard to sex and right/left side. METHODS: Five hundred anteroposterior radiographs of the pelvis of skeletally mature patients (250 of each sex) who did not present any osteoarthrosis, fractures or tumoral or infectious lesions were analyzed. The length and width of the femoral neck, length of the femoral axis, neck-shaft angle and femoral offset were measured. RESULTS: The following means were observed: 36.54 mm for the length of the femoral neck; 37.48 mm for the width of the femoral neck; 108.42 mm for the length of the femoral axis; 130.47° for the neck-shaft angle; and 44.4 mm for the femoral offset. CONCLUSION: The mean values for the main measurements on the proximal femur in Brazilians differed from those of previous studies. It could also be shown that there was a statistically significant mean difference between men and women for all the variables, both on the left and on the right side, and that the men had greater means than the women...

Verificar a geometria do fêmur da população brasileira por meio de estudo radiográfico e correlacionar os valores quanto ao sexo e ao lado direito/esquerdo. MÉTODOS: Foram analisadas 500 radiografias anteroposteriores de bacia de pacientes esqueleticamente maduros, 250 de cada sexo, sem a presença de osteoartrose, fraturas e lesões tumorais ou infecciosas. Foram mensurados os valores do comprimento e da largura do colo do fêmur, do eixo femoral, do ângulo colodiafisário e do offset femoral. RESULTADOS: Observou-se uma média de 36,54 mm do comprimento do colo do fêmur, 37,48 mm da largura do colo do fêmur, 108,42 mm do comprimento do eixo femoral, 130,47° do ângulo colodiafisário e 44,4 mm do offset femoral. CONCLUSÃO: Os valores médios das principais medidas do fêmur proximal dos brasileiros diferem de trabalhos prévios. Foi possível evidenciar também que existe diferença média estatisticamente significante entre homens e mulheres para todas as variáveis, tanto do lado esquerdo quanto do direito, e que os homens tiveram média maior do que as mulheres...

Femoral functional adaptation: a comparison between hunter gatherers and farmers using geometric morphometrics / Adaptación funcional del fémur: una comparación entre cazadores-recolectores y agricultores usando morfometría geométrica

The transition from hunting and gathering to agriculture has been associated with a gracilization in human form, especially in long bones. This has been interpreted as result of an increasingly sedentary lifestyle and reduced workload in the farming populations. However the majority of these evidences have been based on the application of different biomechanical techniques or the qualitative assessment of distinct morphological traits on attachment sites. Hence, this study tried to address whether is possible to distinguish between two different populations (hunter-gatherers and farmers) by quantifying their femoral morphology applying geometric morphometrics. We compared 16 male left femora belonging to two populations of Native Americans from the same geographic region, yet temporally and behaviorally distinct, in order to test if geometric morphometrics were able to differentiate these based solely on the quantitative analysis of shape. The femora were scanned and then small portions of them were segmented in order to generate comparable 3D models. Hundred twelve equidistant landmarks were collected over the whole femoral sections and a Procrustes analysis was performed in order to obtain shape variables. Several PCAs were carried out to elucidate morphometric associations and cross-validated DAs were applied to distinguish between hunter-gatherers and farmers. These procedures were sequentially repeated using different landmarks subsets in order to try to establish the anatomical locations where bone functional adaptation mostly occurs: a) femoral cortex; b) medullary cavity; c) complete femoral section. The results here presented, showed that geometric morphometrics were able to distinguish between the two distinct lifestyles. Moreover, the contrasting results obtained from the analysis of the femoral cortex and the medullary cavity, suggest that long bone remodelling caused by lifestyle differences, mostly occurs on the outer surface of the femoral shaft. This study also showed a relative gracilization of the farmer as compared to the hunter-gatherers.

La transición desde la caza y la recolección a la agricultura ha sido asociada con una gracilización en la forma humana, especialmente en los huesos largos. Esto ha sido interpretado como resultado de un estilo de vida más sedentario y con menor carga de trabajo en las poblaciones agricultoras. Sin embargo, la mayoría de estas evidencias se han basado en técnicas biomecánicas o en la evaluación cualitativa de rasgos morfológicos en los sitios de inserción muscular. Este estudio intentó distinguir entre dos poblaciones diferentes (cazadores-recolectores y agricultores) mediante la cuantificación de su morfología femoral aplicando morfometría geométrica. Dieciséis fémures masculinos pertenecientes a dos poblaciones nativo americanas de la misma región geográfica, aunque temporal y conductualmente diferentes, fueron comparadas con la finalidad de probar si la morfometría geométrica era capaz de distinguirlas. Los fémures fueron escaneados y pequeñas porciones fueron segmentadas para generar modelos 3D. Se colectaron 112 hitos equidistantes sobre toda la superficie femoral y luego se realizó un análisis de Procusto para obtener variables de la forma. Diversos análisis de componentes principales se llevaron a cabo para establecer asociaciones morfométricas, así como también análisis discriminantes con validación cruzada para distinguir entre cazadores-recolectores y agricultores. Estos procedimientos fueron repetidos utilizando diferentes subconjuntos de hitos para establecer donde ocurre mayoritariamente la adaptación funcional del hueso: a) corteza femoral; b) cavidad medular; c) sección femoral completa. Los resultados aquí presentados mostraron que la morfometría geométrica permite distinguir entre ambos modos de vida. Además, los contrastantes resultados obtenidos del análisis de la corteza femoral y cavidad medular, sugieren que el remodelamiento óseo debido a diferentes estilos de vida ocurren mayoritariamente en la superficie de la diáfisis del fémur. Este estudio también mostró una relativa gracilización de la población agricultora al ser comparada con los cazadores-recolectores.

The effect of simvastatin on the regeneration of surgical cavities in the femurs of rabbits

To evaluate the effect of a local application of simvastatin gel in repairing bone defects in the femurs of rabbits. METHODS: Two standard surgical cavities were created in the femoral epiphysis of 18 rabbits. In the simvastatin group (SG), the cavities were filled with a collagen sponge soaked in 0.5 ml of a simvastatin (1 mg) gel, and the cavities were covered with a biological membrane. The bone cavities in the second group (control group) were filled with a blood clot and covered with a biological membrane. On the 7th, 21st and 42nd days, six animals in each group were euthanized, and the femurs were subject to histological evaluation (vascularity, fibrosis, reactive bone formation, osteoblasts, and osteoclasts) and immunohistochemical (anti-VEGF and anti-osteocalcin) analysis. The results were analyzed using a Wilcoxon test (p<0.05). RESULTS: There were significant differences between the two groups: the SG had greater scores in comparison with the CG in terms of the degree of vascularity on the 7th and the 21st days, fibrosis on the 21st day, bone formation reaction on the 21st and the 42nd days and the number of osteoblasts and osteoclasts on the 42nd day. The immunohistochemical expression was also greater for osteocalcin and VEGF on the 7th, 21st and 42nd days. CONCLUSION: Surgical defects created in rabbit femurs were treated locally with simvastatin gel to stimulate bone repair, which promoted an ameliorative effect in the morphological and immunohistochemical markers of bone regeneration.

Preliminary analysis of knee stress in Full Extension Landing

OBJECTIVE: This study provides an experimental and finite element analysis of knee-joint structure during extended-knee landing based on the extracted impact force, and it numerically identifies the contact pressure, stress distribution and possibility of bone-to-bone contact when a subject lands from a safe height. METHODS: The impact time and loads were measured via inverse dynamic analysis of free landing without knee flexion from three different heights (25, 50 and 75 cm), using five subjects with an average body mass index of 18.8. Three-dimensional data were developed from computed tomography scans and were reprocessed with modeling software before being imported and analyzed by finite element analysis software. The whole leg was considered to be a fixed middle-hinged structure, while impact loads were applied to the femur in an upward direction. RESULTS: Straight landing exerted an enormous amount of pressure on the knee joint as a result of the body's inability to utilize the lower extremity muscles, thereby maximizing the threat of injury when the load exceeds the height-safety threshold. CONCLUSIONS: The researchers conclude that extended-knee landing results in serious deformation of the meniscus and cartilage and increases the risk of bone-to-bone contact and serious knee injury when the load exceeds the threshold safety height. This risk is considerably greater than the risk of injury associated with walking downhill or flexion landing activities. .

Femoral biomechanic and microtomography from male ratssubmitted to dietary restriction supplemented with sucrose

Food restriction reduces body weight and influence bone mass and also is correlated with bone mineraldensity (BMD). Mechanisms have been proposed for the loss of BMD after body weight reduction, includingreduced energy intake. Growing 8 wk-old Wistar male rats were randomly divided into Control and Calorierestriction associated with sucrose 30% (CRS). These animals were subjected to intermittent food restrictionduring 8 weeks and had free access to tap water and sucrose30% in distilled water. The rats were euthanizedat the end of week 8, blood collected from abdominal aorta artery, femurs cleaned of adherent soft tissues,scanned using dual energy X-ray absorptiometry, structural and material properties determined by three-pointbending testing in the mid-diaphyseal region, bone surface tested in a microhardness tester and microstructurewas assessed in a microcomputer tomography. In CRS animals body weight decreased significantly relative tothe Control animals. There was a clear option for high-sucrose beverage in CRS animals. No difference wasobserved in biochemical, densitometric and biomechanical analyzes. Results from micro CT showed onlysignificant difference in connectivity of trabecular bone. It has been suggested that rats submitted to foodrestriction consumed sugar not because of its inherent palatability, but in order to alter their macronutrientbalance and animals need to meet energy demands in high-sucrose.

Efeitos de um programa de exercícios em grupo sobre a força de preensão manual em idosas com baixa massa óssea / Effects of a group exercise program on handgrip strength of elderly women with low bone mass

OBJETIVOS: Avaliar os efeitos de um programa de exercícios sobre a força de preensão ma­nual (FPM) em idosas com baixa massa óssea. SUJEITOS E MÉTODOS: Trinta e seis idosas foram randomizadas em: grupo intervenção - GI (n = 18) e grupo controle - GC (n = 18), avaliadas pelo teste de FPM, utilizando-se um dinamômetro de mão. O GI realizou exercícios de força muscular, equilíbrio e mobilidade funcional. O GC realizou alongamentos. Ambos os grupos realizaram duas sessões semanais de 50 minutos, durante quatro meses. RESULTADOS: O GI apresentou aumento da FPM em 31,38% (p = 0,00). O GC não mostrou diferença. Houve correlações entre a FPM e a densidade mineral óssea (DMO) do colo do fêmur (r = 0,582, p = 0,003) e do fêmur total (r = 0,485, p = 0,01). CONCLUSÃO: Os resultados sugerem uma tendência ao incremento da FPM de idosas e mostraram correlações significantes entre a FPM e a DMO.

OBJECTIVES: To evaluate the effects of an exercise program on handgrip strength (HS) in elderly women with low bone mass. SUBJECTS AND METHODS: Thirty-six elderly women were randomized to the intervention group - GI (n = 18) and control group - GC (n = 18). Participants were evaluated by means of a HS test, using a handgrip dynamometer. GI performed strength, balance and functional mobility exercises, and GC performed stretching exercises. Both groups had sessions twice a week for 50 minutes, during 4 months. RESULTS: GI had a significant increase in handgrip strength equal to 31.38%. No differences were observed in GC. There were correlations between HS test and bone mineral density (BMD) of the femoral neck (r = 0.582, p = 0.003) and total femur (r = 0.485, p = 0.01). CONCLUSION: Results indicate a propensity to increase elderly HS, and showed significant correlations between HS and BMD.

Comparative osteometric study of long bones in Yankasa sheep and red Sokoto goats / Estudio osteométrico comparativo de los huesos largos entre oveja Yankasa y las cabras rojas Sokoto

A morphometric study was undertaken on the long bones in the two predominant breeds of small ruminant in Northern Guinea Savanna zone of Nigeria, to determine their anatomical differences and thus, provide a means of differentiating the remains of these two species during zooarchaeological studies and gross anatomy practical session. The pelvic and pectoral limbs from thirty animals (15 Yankasa sheep and 15 Red Sokoto goats) of both sexes were used for this study. The long bones of the pectoral limbs considered were the humerus, radius, ulna and metacarpal III while those of the pelvic limbs were the femur, tibia and metatarsal III. The parameters considered were the mean weights, lengths and diameters of the proximal extremity, mid-shaft and distal extremities of these bones. The result of this study showed that there is a very high statistically significant difference (p < 0.001) in the length of long bones between the two species, with that of the Yankasa sheep being significantly longer than the Red Sokoto goat. Also, the differences in weights as well as diameters of the proximal, middle and distal shafts of the tibia between the two species are of a very high statistical importance (p < 0.001). Conversely, the differences in the proximal and distal diameters of the femur between the two species are not statistically significant (p > 0.05). Factors that may be responsible for these differences were discussed. It is concluded that the bones of the Yankasa sheep and Red Sokoto goat can be differentiated by the disparity in the length of these long bones or the disparity in the entire morphometry of the tibia bone.

Se realizó un estudio morfométrico en los huesos largos en las dos razas predominantes de pequeños rumiantes del norte de Guinea, zona de Sabana de Nigeria, para determinar sus diferencias anatómicas y proporcionar un medio de que permita diferenciar los restos, de estas dos especies, durante los estudios zooarqueológico y en además en práctica de anatómica. Se utilizaron los miembros pélvicos y pectorales de treinta animales (15 ovejas Yankasa y 15 cabras rojas de Sokoto) de ambos sexos. Los huesos largos de los miembros pectorales considerados fueron: húmero, radio, ulna y III metacarpiano, mientras que en los miembros pélvicos fueron: fémur, fíbula y el III metatarso. Los parámetros considerados fueron los pesos medios, longitudes y diámetros de la extremidad proximal y tercios medio y distal de estos huesos. Los resultados mostraron que existe una diferencia altamente significativa (p <0,001) en la longitud de los huesos largos entre las dos especies. Los huesos en las ovejas Yankasa son significativamente más largos que los de la cabra roja de Sokoto. Además, de las diferencias en el peso, así como los diámetros de los ejes proximal, media y distal de la fíbula entre las dos especies son estadísticamente significativos (p <0,001). Por el contrario, las diferencias en los diámetros proximal y distal del fémur entre las dos especies no son estadísticamente significativas (p> 0,05). Fueron discutidos los factores que pueden ser responsables de estas diferencias. Se concluye que los huesos de las ovejas y cabras Yankasa Red Sokoto, se pueden diferenciar por la disparidad en la longitud de los huesos largos o en la morfometría de la tibia.

Establishment of femoral 3D finite element model and validation of injury biomechanics / 法医学杂志

OBJECTIVE@#To investigate the feasibility of creating an effective femoral finite element model from medical images of CT scan with Mimics software, and to provide a good model for femoral fracture biomechanics.@*METHODS@#CT images of femur were obtained from 16-slice spiral CT, which were subsequently imported into Mimics software according to DICOM standard. The 3D femoral finite element model was developed, meshed and assigned with material properties. The feasibility of the model was tested and validated with LS-DYNA in different modes including vertical load of 1 000 N, 3-points bending and side impacts.@*RESULTS@#Five hundred twenty-one scanning images were available and reconstructed to create a femoral finite element model consisting of 17 879 nodes and 106 834 tetrahedron elements. The average stress on the femoral neck nodes under vertical load was (3.209 7 +/- 1.373 5) MPa. Strain-deflection curve in 3-points bending test was consistent with Kennedy's study results. The results of the side impact test were in accordance with the forensic anatomical findings.@*CONCLUSION@#The established model should be applicable to femoral collision biomechanics studies.

Efeitos do treinamento físico sobre a resistência mecânica do terço proximal do fêmur de ratos / Effects of physical training on the mechanical resistance of rat femur proximal thirds

OBJETIVO: Analisar o comportamento mecânico do terço proximal do fêmur de ratos submetidos ao treinamento aeróbio e resistido crônicos. MÉTODOS: Ratos Wistar machos (80 dias, 300 a 350 g) foram divididos em 3 grupos (n=8 por grupo): Treinamento aeróbio/8 semanas (TA), Treinamento resistido/8 semanas (TR) e controle/8 semanas (CO). Ao término do período de treinamento os animais foram sacrificados e o fêmur direito coletado. Para análise do comportamento mecânico do fêmur foram realizados ensaios de flexo-compressão. RESULTADOS: O treinamento resistido ocasionou redução significante da força máxima (Fmáx) do fêmur. Por outro lado, promoveu um aumento (23,7 por cento) relevante, porém não significante, da deformação da força máxima (DFmáx). O treinamento aeróbio não afetou a Fmáx, porém promoveu uma redução (26,6 por cento) considerável, também não significante, da DFmáx. CONCLUSÕES: Os resultados demonstram que o treinamento resistido e aeróbio, promoveram redução da Fmáx e da DFmáx óssea, respectivamente. Os dados evidenciam uma ação diferencial de ambos os modelos de treinamento físico sobre as propriedades mecânicas do fêmur de ratos.

OBJECTIVE: To analyze the mechanical behavior of rat femur proximal thirds submitted to chronic aerobic and resistance training. METHODS: Male Wistar rats (80 days of age, weighing 300 to 350 g) were divided into 3 groups (n=8 per group): control (CO), aerobic training (TA) and resistance training (TR). At the end of the training, the animals were euthanized and the right femur was collected. Flexion-compression tests were carried out to analyze the mechanical behavior of the femurs. RESULTS: The resistance training promoted a significant reduction in maximum force (Fmáx) of the femur. However, it also promoted a relevant increase (23.7 percent), though without statistical significance, in maximum force deformation (DFmáx). The aerobic training did not affect maximum force, however, it caused a considerable reduction in DFmáx (26.6 percent), though this was also not statistically significant. CONCLUSIONS: The results show that resistance and aerobic training promoted a reduction in the Fmáx and DFmáx, respectively. The data showed a different response of both physical training models on the mechanical properties of the rat femurs.

Influência da composição corporal e da idade sobre a densidade óssea em relação aos níveis de atividade física / Influence of body composition and age on bone density in relation to levels of physical activity

OBJETIVO: Verificar em relação ao nível de atividade física (NAF) o quanto cada componente da composição corporal e a idade influenciam na densidade óssea (DO). MÉTODOS: Amostra de 22 homens e 42 mulheres (21 a 51 anos) classificados com NAF recomendado e não recomendado para a saúde. A DO do fêmur foi mensurada por meio da DXA. RESULTADOS: Por meio da análise de regressão linear múltipla stepwise (p < 0,05), a idade explicou negativamente a DO em todos os grupos, exceto nos homens com NAF recomendado. Nas mulheres com NAF não recomendado, a gordura relativa (G%) e a massa gorda (MG) explicaram a DO em todas as regiões de interesse no fêmur, com aumento de até 0,007 g/cm² por quilograma de MG. CONCLUSÃO: A DO na área de Ward sofre maior influência da idade nas mulheres. A MG e a G por cento exercem influência positiva sobre a DO das mulheres com NAF não recomendado.

OBJECTIVES: Verify the physical activity level (PAL), to what extent each body composition component and age influence bone density (BD). METHODS: Samples of 22 men and 42 women (21-51 years) classified with recommended and not recommended PAL for health. The femur's BD measured using DXA. RESULTS: Using a analyzing the stepwise linear regression (p < .05), the age explained negatively BD for all groups, except men with recommended PAL. Among women group with not recommended PAL, the relative fat (%F) and body fat (BF) explained the BD increasing to 0.007 g/cm² per BF kilogram in all regions of interest in the femur. CONCLUSION: The BD in Ward's area has been mostly influenced by age in women. The FM and percentF have positive influence on BD among women with low PAL.

Biomechanics and structural adaptations of the rat femur after hindlimb suspension and treadmill running

We microscopically and mechanically evaluated the femurs of rats subjected to hindlimb unloading (tail suspension) followed by treadmill training. Female Wistar rats were randomly divided into five groups containing 12-14 rats: control I (118 days old), control II (139 days old), suspended (tail suspension for 28 days), suspended-released (released for 21 days after 28 days of suspension), and suspended-trained (trained for 21 days after 28 days of suspension). We measured bone resistance by bending-compression mechanical tests of the entire proximal half of the femur and three-point bending tests of diaphyseal cortical bone. We determined bone microstructure by tetracycline labeling of trabecular and cortical bone. We found that tail suspension weakened bone (ultimate load = 86.3 ± 13.5 N, tenacity modulus = 0.027 ± 0.011 MPa·m vs ultimate load = 101.5 ± 10.5 N, tenacity modulus = 0.019 ± 0.006 MPa·m in control I animals). The tenacity modulus for suspended and released animals was 0.023 ± 0.010 MPa·m vs 0.046 ± 0.018 MPa·m for trained animals and 0.035 ± 0.010 MPa·m for control animals. These data indicate that normal activity and training resulted in recovered bone resistance, but suspended-released rats presented femoral head flattening and earlier closure of the growth plate. Microscopically, we found that suspension inhibited new bone subperiosteal and endosteal formation. The bone disuse atrophy secondary to hypoactivity in rats can be reversed by an early regime of exercising, which is more advantageous than ordinary cage activities alone.

Reference values for areal bone mineral density among a healthy Mexican population / Valores de referencia para la densidad mineral ósea expresada en área para una población mexicana sana

OBJECTIVE: Compare the influence of ethnicity in the prevalence of osteopenia and osteoporosis in various Mexican populations using two normal dual X-ray absorptiometry (DXA) reference databases: manufacturer's incorporating US Hispanic population and a normal mestizo Mexican population. MATERIAL AND METHODS: MMP included 9 946 subjects participating in an ongoing long-term cohort study focusing on lifestyle and chronic diseases, of which 6 487 MMP males and females aged 7 to 80 years were the normal subjects used to determine bone density T- and Z-scores, following WHO criteria, and peak bone mass values. Abnormal bone mass density values estimated by the manufacturer's and peak bone mass reference values were compared. RESULTS AND CONCLUSIONS: Our results show that by using the manufacturer's T-score values in the mestizo Mexican population we are underestimating the number of abnormal bone mass BMD populations.

OBJETIVO: Comparar la influencia de la etnicidad en la prevalencia de osteopenia y osteoporosis en varias poblaciones mexicanas utilizando dos bases de referencia normal de densitometría de rayos X (DXA): referencia del fabricante que incorpora hispanos en Estados Unidos y datos de una población mestiza mexicana. MATERIAL Y MÉTODOS: Un total de 9 946 sujetos de población mestiza mexicana participantes en una cohorte de largo plazo dirigida al estudio de estilos de vida y ocurrencia de enfermedades crónicas; de los cuales 6 487 sujetos sanos de ambos sexos, con edad entre los 7 y los 80 años, fueron utilizados para determinar los valores T, Z, de acuerdo a los criterios de la OMS, así como a los valores de masa ósea pico. Se compararon los casos de densidad mineral ósea anormal de acuerdo a los valores de referencia del fabricante y los valores de masa ósea pico de la población mestiza. RESULTADOS Y CONCLUSIÓN: Las bases de referencia del fabricante subestima significativamente el número de casos con densidad mineral ósea anormal en la población mestiza mexicana.

Comparación de las características mecánicas estáticas del fémur aislado de perro, con y sin la colocación de una placa de ortopedia fabricada en polipropileno / Compare the mechanical statistical characteristics of dog femur isolet, with or without placing to an orthopedic píate made of polypropylene

Los objetivos generales fueron: evaluar resistencia a la compresión del fémur derecho aislado y del fémur izquierdo osteotomizado transversalmente fijado con una placa ortopédica fabricada en polipropileno, y comparar las características mecánicas estáticas entre ambos. Este trabajo se realizó mediante la confección de un modelo experimental de carga constituido por un fémur de mamífero (perro) en condiciones aisladas. Se utilizaron los huesos fémur de 13 perros mestizos, adultos jóvenes, de talla mediana a grande. Para los pruebas se utilizó una máquina servohidráulica para ensayos estáticos y dinámicos Amsler Wolpert. Se utilizó para el tratamiento de los datos, el test estadístico de diferencias de medias para muestras pareadas dependientes. Como resultado del análisis de las curvas se obtuvo que: el fémur derecho soportó antes de la falla, entre 4,02 a 8,47 KN de carga (= 6,66 KN) con una deformación de 2,02 a 5,09 mm (= 3,66 mm). En tanto el conjunto fémur izquierdo + placa ortopédica soportó antes de la falla, entre 3,05 a 5,61 KN de carga (= 4,49 KN) con una deformación de 2 a 4.5 mm (= 3 mm). Como conclusión, es posible afirmar que hay diferencias en la resistencia a la carga compresiva entre el fémur derecho y su contralateral izquierdo + placa ortopédica.

The general aims were: to evaluate the resistance to compression of the right femur isolated and that of the left femur transversally osteotomized fixed to an orthopedic plate made of polypropylene and to compare the mechanical statistical characteristics between both. This work was carried out by performing an experimental charge pattern made of a mammal femur (dog) under isolated conditions. Femur bones of 13 hybrid young adult dogs of medium to large size were used. A servohydric engine was used for the Amsler Wolpert static and dynamic essays. The mean difference statistical test for depending paired samples was used for the evaluation of data. As a result of the curves analysis it was obtained that: before failure the right femur underwent a charge of 4.02 to 8.47 KN (= 6.66 KN) with a deformation of 2.02 to 5.09 mm (= 3.66mm) while the charge that the left femur + orthopedic plate underwent before de failure was of 3.05 to 5.61 KN ( = 4.49KN) with a deformation of 2 to 4.5 mm ( = 3mm). As a conclusion it might be stated that there are differences in the resistance to the compressive charge between right femur and its left contra lateral + the orthopedic plate.

Estudio biomecánico de resistencia en fémur porcino y predictibilidad de zona de fractura / Biomechanical study of porcine femur resistance and predictability of fracture zone

During everyday activities, bones are submitted to the action of different strengths. While walking, the femur must support loads up to 3 times the body weight. It is for this that the need of knowing the mechanical behavior of the femur submitted to different loads and the place where the fracture would occur is born. This study analyzes, through experimental testing, the maximum resistance of the porcine femur, mechanically comparable to the human femur, submitted to different strengths, to obtain the location of fracture and compare the results obtained with computational simulation and with information described for human femur.

Durante actividades de la vida diaria, los huesos se ven sometidos a la acción de diferentes fuerzas. En la marcha, el fémur debe soportar cargas de hasta 3 veces el peso corporal. Es por esto que nace la inquietud de conocer el comportamiento mecánico del fémur sometido a distintos tipos de cargas, y el lugar de falla donde se produciría una fractura. Este estudio analiza, mediante ensayo experimental, la resistencia máxima del fémur porcino, mecánicamente comparable al fémur humano, frente a distintas cargas, para obtener así el sitio de fractura y luego comparar los resultados obtenidos con simulación computacional y con datos descritos para el fémur humano.

Efetividade dos exercícios em cadeia cinética aberta e cadeia cinética fechada no tratamento da síndrome da dor femoropatelar / Effectiveness of the open and closed kinetic chain exercises in the treatment of the patellofemoral pain syndrome

O objetivo deste estudo foi analisar os efeitos terapêuticos dos exercícios em cadeia cinética aberta (CCA) e cadeia cinética fechada (CCF) no tratamento da síndrome da dor femoropatelar (SDFP). Para tanto, 24 voluntários portadores de SDFP foram aleatoriamente divididos em dois grupos: grupo I (n = 12): realizou exercícios em CCA; grupo II (n = 12): realizou exercícios em CCF. Os grupos foram submetidos a oito semanas consecutivas de tratamento, que consistiu de três sessões semanais realizadas em dias alternados. Para análise dos padrões de ativação dos músculos vasto medial oblíquo (VMO) e vasto lateral (VL) os sinais eletromiográficos (EMG) foram adquiridos com eletrodos bipolares de superfície, quantificados pela raiz quadrada da média (root mean square RMS) e normalizados pela contração isométrica voluntária máxima do quadríceps. Por meio de escalas avaliou-se a intensidade da dor e funcionalidade dos voluntários. A análise dos valores da razão VMO/VL nos grupos I e II demonstrou que não houve diferenças significativas entre os tempos pré e pós-tratamento nas fases concêntrica (p > 0,05) e excêntrica (p > 0,05) dos exercícios em CCA e CCF. Apesar disso, o músculo VMO apresentou menor taxa de ativação em relação ao VL na fase excêntrica do exercício em CCF. Foram encontrados aumentos significativos na funcionalidade (p < 0,05) e redução da intensidade da dor (p < 0,05) entre os tempos pré e pós-tratamento em ambos os grupos, porém, o grupo II mostrou-se superior ao grupo I nestas duas variáveis. Os resultados deste estudo sugerem que, de acordo com as condições experimentais utilizadas, os exercícios em CCA e CCF não provocaram mudanças nos padrões de ativação EMG dos músculos VMO e VL; entretanto, promoveram melhora da funcionalidade e redução da intensidade da dor após oito semanas de intervenção, sendo que os exercícios em CCF foram superiores aos em CCA.

The aim of this study was to analyze the therapeutic effects of the open kinetic chain (OKC) and closed kinetic chain (CKC) exercises to treat the patellofemoral syndrome (PFSD). For this, 24 volunteers, bearers of the PFSD were randomly divided in two groups: group I (n = 12) performed the OKC exercises; group II (n = 12) performed the CKC exercises. Both groups were submitted to eight consecutive weeks of treatment consisting of three weekly sessions performed in alternate days. To analyze the activation pattern of the vastus medialis oblique (VMO) and the vastus lateralis (VL) muscles, the electromyographic signals (EMG) were collected using bipolar surface electrodes quantified by the root mean square (RMS) normalized by the maximal voluntary isometric contraction of the quadriceps. The pain intensity and the functionality of the volunteers were assessed using scales. The analysis of the amounts of the VMO/VL ratio in both groups I and II showed no significant differences as to the pre- and post-treatment times in the concentric (p > 0.05) and eccentric (p > 0.05) phases of the OKC and CKC exercises. Despite of this, the VMO muscle presented a lower activation rate compared to the VL in the eccentric phase of the CKC exercise. It was found significant increases in the functionality (p < 0.05), and a reduction in the pain intensity (p < 0.05) between the pre- and post-treatment times in both groups, but group II showed higher amounts compared to group I in both variables. The results found in this study suggest that according to the conditions of the trial, the OKC and CKC exercises provoke no changes in the patterns of the EMG activation in the VMO and VL muscles. However, they promoted an improvement in the functionality and a reduction in the pain intensity after the eight week intervention, and the CKC exercises presented better performances than OKC exercises.

El objetivo de este estudio era analizar los efectos terapéuticos de los ejercicios en la cadena cinética abierta (CCA) y la cadena cinética cerrada (CCC) en el tratamiento del síndrome del dolor femoropatelar (SDFP). Para esto se ofrecieron 24 portadores de SDFP que fueron divididos aleatoriamente en dos grupos: Se agruparon en: los ejercicios I en CCA (el n = 12); y los ejercicios II en CCC (el n = 12). Los grupos se sometieron a ocho semanas consecutivas de tratamiento que consistió en tres sesiones semanales logradas en los días alternados. Para los análisis de los modelos de activación de los músculos medio oblicuo (VMO) y vasto lateral (VL) las señales electromiográficas (EMG) adquiridas con los electrodos bipolares de superficie, cuantificaron por la raíz cuadrada del promedio (la raíz el cuadrado - RMS) y se normalizó por el máximo de la reducción isométrico voluntario del cuádriceps. A través de balanzas se evaluó la intensidad del dolor y la funcionalidad de los voluntarios. El análisis de los valores de la razón VMO/VL en los grupos I y II demostramos que no había diferencias significantes entre la veces de tiempos pre y post-tratamiento en las fases concéntricas (el p > 0,05) y excéntricas (el p > 0,05) de los ejercicios en CCA y CCC. A pesar de eso, el músculo VMO presentó un punto de activación más pequeño respecto a VL en la fase excéntrica del ejercicio en CCF. En ellos se encontraron aumentos significantes en la funcionalidad (p < 0,05) y en la reducción de la intensidad del dolor (p < 0,05) entre veces de tiempo y post-tratamiento en ambos grupos, sin embargo, el de grupo II se mostraron superiores al grupo I en estas dos variables. Los resultados de este estudio sugieren que, de acuerdo con las condiciones experimentales usadas, los ejercicios en CCA y CCC no provocaron los cambios en los modelos de activación EMG de los músculos VMO y VL, sin embargo, ellos promovieron mejora de la funcionalidad y reducción de la intensidad...

Bone mineral density of lumbar spines and proximal femur in the normal northeastern Thai women.

OBJECTIVE: To determine reference data for age-matched bone mineral density (BMD) of normal northeastern Thai women. MATERIAL AND METHOD: 350 northeastern Thai women aged 20-70 years were prospectively studied. After interview, the subjects were examined for BMD of lumbar spines and proximal femur. Mean BMD of each group was determined for each skeletal site. Standard deviation (SD) of BMD in the peak group was calculated to determine BMD cutoff level for diagnosing osteoporosis. RESULT: Peak average BMD of lumbar spines was at 40-45 years, whereas peak BMD of proximal femur was at 35-40 years. Mean value of peak BMD of lumbar spines and proximal femur was 1.226 and 1.035 g/cm2, respectively. According to T-score less than -2.5 SD criteria, osteoporosis of lumbar spines and proximal femur was considered when measured BMD was below 0.889 and 0.785 g/cm2, respectively. CONCLUSION: Our study provided the BMD reference data for northeastern Thai women.