scholarly journals Femoral neck strain prediction during level walking using a combined musculoskeletal and finite element model approach

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245121
Author(s):  
Zainab Altai ◽  
Erica Montefiori ◽  
Bart van Veen ◽  
Margaret A. Paggiosi ◽  
Eugene V. McCloskey ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Neck ◽  
Gait Cycle ◽  
Small Sample Size ◽  
Small Sample ◽  
The Body ◽  
Contact Forces ◽  
Principal Strain ◽  
Peak Strain ◽  
Joint Contact

Recently, coupled musculoskeletal-finite element modelling approaches have emerged as a way to investigate femoral neck loading during various daily activities. Combining personalised gait data with finite element models will not only allow us to study changes in motion/movement, but also their effects on critical internal structures, such as the femur. However, previous studies have been hampered by the small sample size and the lack of fully personalised data in order to construct the coupled model. Therefore, the aim of this study was to build a pipeline for a fully personalised multiscale (body-organ level) model to investigate the strain levels at the femoral neck during a normal gait cycle. Five postmenopausal women were included in this study. The CT and MRI scans of the lower limb, and gait data were collected for all participants. Muscle forces derived from the body level musculoskeletal models were used as boundary constraints on the finite element femur models. Principal strains were estimated at the femoral neck region during a full gait cycle. Considerable variation was found in the predicted peak strain among individuals with mean peak first principal strain of 0.24% ± 0.11% and mean third principal strain of -0.29% ± 0.24%. For four individuals, two overall peaks of the maximum strains were found to occur when both feet were in contact with the floor, while one individual had one peak at the toe-off phase. Both the joint contact forces and the muscular forces were found to substantially influence the loading at the femoral neck. A higher correlation was found between the predicted peak strains and the gluteus medius (R2 ranged between 0.95 and 0.99) than the hip joint contact forces (R2 ranged between 0.63 and 0.96). Therefore, the current findings suggest that personal variations are substantial, and hence it is important to consider multiple subjects before deriving general conclusions for a target population.

scholarly journals A COMPARATIVE CLINICAL STUDY ON JARA WITH RESPECT TO AGEING PROCESS WITH ASHWAGANDHA RASAYANA AND MATRA BASTI

2016 ◽  
Author(s):  
Singh Binod Kumar ◽  
Bharkher D.L
Keyword(s):  
Life Expectancy ◽  
Small Sample Size ◽  
Small Sample ◽  
The Body ◽  
World Health ◽  
Ageing Process ◽  
Health Security ◽  
Chief Complaints ◽  
Comparative Clinical Study ◽  
Later Phase

The problem of ageing is experienced by all the countries. According to World Health statistics the life expectancy of Nepalese people has risen from 58.91 years to 67.86 years (1996 to 2015). Ageing is emerging issue in Nepal as well as global. Its tempo is expected to be unexpectedly fast as mortality continues to decline and life expectancy continues to increase. Ayurveda the science of life has observed ageing as a Jara avastha, which is a later phase of life, it is natural, inevitable phenomenon, in which maximum decline of bodily elements that may become as major cause of disability and functional dependency requiring services that affect many sectors of economy, health, security, income, housing, transportation etc. Jara chikitsa has been mentioned as one independent Anga in Ashtanga Ayurveda where Rasayana therapy is capable to impede the ageing process and to delay the degenerative process in the body. In this study we measured the effectiveness of Ashwagandha rasayana and Matra basti and compared with the Ashwagandha Rasayan only in Jara avastha. A total of thirty elderly patients were selected and divided in two groups A and B, given them either Ashwagandha Rasayana with Matra basti or Ashwagandha rasayana in prescribed doses for 45 days. Changes in the subjective complaints, objective parameters of the patients and appearance of adverse events were also evaluated. Both the groups provided better results on the chief complaints But, comparison in between both the groups is insignificant, that may be due to small sample size.

Role of Trace andamp; Toxic Elements in the Development of Anaemia in School going population of Hyderabad

2019 ◽  
Vol 41 (3) ◽  
pp. 405-405
Author(s):  
Junaid Ali Thebo Junaid Ali Thebo ◽  
Shaista Khan Shaista Khan ◽  
Abdul Aziz Shaikh Abdul Aziz Shaikh ◽  
Nasren Thebo Nasren Thebo ◽  
Ghulam Nabi Ghulam Nabi ◽  
...  
Keyword(s):  
Trace Elements ◽  
Small Sample Size ◽  
Venous Blood ◽  
Research Work ◽  
Small Sample ◽  
The Body ◽  
Control Group ◽  
Severe Anemia ◽  
Informed Consent Form ◽  
Lead Levels

The aim of this research work was to measure the concentration of essential trace elements, including serum copper, iron and zinc in children suffering from anemia, and also to investigate the effect of heavy metal like lead on causing anemia. The study has been performed on school going children living in Hyderabad, which is a mini industrialized city. The study was carried out in anemic children studying in different schools of Hyderabad having different age groups. 10 ml venous blood samples were obtained after an informed consent form was signed.The samples were used to analyzed the trace elements (Fe,Cu, Zn) and toxic metal Lead (Pb). Trace elements include zinc and copper were found elevated in anemic children than healthy one, Copper is involved in many vital mechanisms in the body, energy production, connective tissue formation, and Fe metabolism, whereas copper found low with relation to the iron in anemic children because copper helps in the absorption of iron. Zinc is an essential micronutrient demanded by living being because of its significant position in-cooperation with structural constituent of proteins and as a cofactor in enzyme catalysis, there is difference between zinc and iron, they have been found to inhibit each other’s absorption due to their competitive absorption pathways. Increased zinc levels found in children with low iron content, whereas control group have normal results of these elements which may be due to their dietary management. The results revealed the environmental pollution and the associated health risks on exposure to lead. Pb concentrations whereas the current research stated a considerable relationship of mild and severe anemia with 10-42.2μg/dl Pb concentrations, the variation in results may be due to a small sample size in the current study, Drinking water from corrosion of plumbing systems through the use of lead sellers and other lead containing materials in connecting household plumbing to public water supplies. Ground and surface water are also contaminated by lead consuming industry and agricultural activities. The concentrations of Pb greater than or equal to (≥)10 μg/dl in children related with an increased threat of mild and severe anemia, diminishing iron absorption . High Lead levels were related with lower concentrations of iron, ferritin and copper, in this study it was found that high levels of lead were found mostly in boys. Lead levels have also found in control group which was below 5 ug/dl, according to WHO ≥ 10 ug/dl is considered as high.

Firms’ Specific Determinants of Capital Structure: An Analysis into Construction Firms in Malaysia and Singapore

2021 ◽  
Vol 7 ◽  
pp. 76-91
Author(s):  
Siti Zulaikha Binti Upilin ◽  
Hapsah S.Mohammad
Keyword(s):  
Capital Structure ◽  
Firm Size ◽  
Small Sample Size ◽  
Panel Data Analysis ◽  
Agency Cost ◽  
Small Sample ◽  
The Body ◽  
Construction Firms ◽  
The Impact ◽  
The Capital Structure

The study aims to examine the firm-specific factors such as firm size, profitability and asset tangibility in the capital structure decisions (leverage) on a sample of twenty construction firms in Malaysia and Singapore from 2009 to 2018, with 200 observations. The sample firms are chosen based on convenience sampling technique and the availability of the data. Prior studies documented inconclusive findings on the determinants of capital structure and different industries tend to reveal different patterns of relationship. In addition, the empirical evidence on comparative analysis between construction firms in Malaysia and Singapore is lacking. Hence, the objective of this study is to extend the prior work by investigating the impact of the determinants on capital structure on the construction firms in Malaysia and Singapore. The study uses panel data analysis to test the effectivity of trade-off, pecking order and agency cost theories of capital structure. The empirical findings reveal positive and significant association between firm size and capital structure for Singapore firms. Meanwhile, profitability and asset tangibility correlate negatively with capital structure. As for Malaysian firms, the three determinants exhibit insignificant association with the capital structure. The study only examines 10 construction firms in Malaysia and 10 construction firms in Singapore, therefore, the small sample size becomes the limitation of the study. Nevertheless, the findings of this study may contribute to the body of knowledge on the importance of some firm-specific determinants such as profitability, tangible assets, and firm size in order to determine the optimal level of capital structure for firms in these countries.

The Influence of Different Parameters of Remodeling Rule and Walking Speed on Resultant Density Distribution of the Proximal Femur

2007 ◽  
Author(s):  
Ali Marzban ◽  
Hamid Nayeb-Hashemi ◽  
Paul K. Canavan
Keyword(s):  
Bone Density ◽  
Density Distribution ◽  
Hip Joint ◽  
Proximal Femur ◽  
Gait Cycle ◽  
Initial Conditions ◽  
Contact Forces ◽  
Loading Conditions ◽  
Fast Speed ◽  
Joint Contact

The process of adaptive bone remodeling can be described mathematically and simulated with a self-optimizing finite element method (FEM) model. The aim of this study was to understand the effect of the basic remodeling rule on the bone density distribution of the proximal femur affected by the muscle loadings and the hip joint contact forces during normal gait (walking). The basic remodeling rule, which is an objective function for an optimization process relative to external load, was applied to predict the bone density. The purpose of the process is to obtain a constant value for the strain energy per unit bone mass, by adapting density modeling. The precise solution is dependent on the magnitude and direction of loads, loading rate, initial conditions and the parameters in the remodeling rule. In this study, we applied adaptive bone density remodeling under both static and dynamic loading conditions. In the static case, the forces at different phases in the gait cycle were statically applied as boundary conditions. The density distributions from these loadings were averaged to find the density distribution in the proximal femur. Three different initial densities were considered to investigate the effect of initial conditions. The influence of different parameters and functions on the density distribution and its convergence rate was also investigated. Furthermore, effect of changing of muscle loading and hip joint contact forces on resultant mass and density distribution of proximal femur was studied. In the dynamic approach, the forces of different phases of gait cycle were applied during different gait cycle’s times of 1.27 second (slow speed), 1.11 second (normal speed), 1.01 second (moderately fast speed), and 0.83 second (very fast speed). Although the results of bone density adaptations in both approaches were comparable with an example of an actual bone density distribution of the femoral head, neck and the proximal femoral shaft; the converged density distribution in the static approach was smoother and more realistic. It was shown that by applying more loading conditions through the gait cycle the converged density distribution is smoother. The resultant density distribution was more comparable with actual proximal femur compared to past studies.

scholarly journals The development of a segment-based musculoskeletal model of the lower limb: introducing F ree B ody

2015 ◽  
Vol 2 (6) ◽  
pp. 140449 ◽  
Author(s):  
Daniel J. Cleather ◽  
Anthony M. J. Bull
Keyword(s):  
Lower Limb ◽  
Musculoskeletal Model ◽  
The Body ◽  
Contact Forces ◽  
Biomechanical Analysis ◽  
Simultaneous Optimization ◽  
Muscle Forces ◽  
Phase Errors ◽  
Vertical Jumping ◽  
Joint Contact

Traditional approaches to the biomechanical analysis of movement are joint-based; that is the mechanics of the body are described in terms of the forces and moments acting at the joints, and that muscular forces are considered to create moments about the joints. We have recently shown that segment-based approaches, where the mechanics of the body are described by considering the effect of the muscle, ligament and joint contact forces on the segments themselves, can also prove insightful. We have also previously described a simultaneous, optimization-based, musculoskeletal model of the lower limb. However, this prior model incorporates both joint- and segment-based assumptions. The purpose of this study was therefore to develop an entirely segment-based model of the lower limb and to compare its performance to our previous work. The segment-based model was used to estimate the muscle forces found during vertical jumping, which were in turn compared with the muscular activations that have been found in vertical jumping, by using a Geers' metric to quantify the magnitude and phase errors. The segment-based model was shown to have a similar ability to estimate muscle forces as a model based upon our previous work. In the future, we will evaluate the ability of the segment-based model to be used to provide results with clinical relevance, and compare its performance to joint-based approaches. The segment-based model described in this article is publicly available as a GUI-based M atlab ® application and in the original source code (at www.msksoftware.org.uk ).

Knee Contact Characteristics During Drop Landing Exercise

2017 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Ricardo Moreno
Keyword(s):  
Inverse Dynamics ◽  
Contact Point ◽  
Standing Position ◽  
The Body ◽  
Contact Forces ◽  
Drop Landing ◽  
Joint Contact ◽  
Reaction Forces ◽  
The Subject ◽  
D Model

This work investigates the human leg joint contact characteristics during a drop-landing exercise. The contact characteristics consist of tibio-femoral contact forces and contact point, and hip contact forces. An inverse dynamics 2-D model of human leg is used on this ballistic task in order to simplify computation. Experimental data used show a maximum of 100 degrees of flexion angle and ground reaction forces up to 4 times the body weight. All contact forces show a pattern in which they reach large magnitudes at the beginning of landing, decreasing as the subject end the exercise with a standing position.

scholarly journals Locomotion Mode Recognition with Inertial Signals for Hip Joint Exoskeleton

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Gang Du ◽  
Jinchen Zeng ◽  
Cheng Gong ◽  
Enhao Zheng
Keyword(s):  
Hip Joint ◽  
Gait Cycle ◽  
Inertial Sensors ◽  
Recognition Accuracy ◽  
Small Sample Size ◽  
Small Sample ◽  
Joint Angles ◽  
Practical Applications ◽  
Mode Recognition ◽  
Locomotion Mode

Recognizing locomotion modes is a crucial step in controlling lower-limb exoskeletons/orthoses. Our study proposed a fuzzy-logic-based locomotion mode/transition recognition approach that uses the onrobot inertial sensors for a hip joint exoskeleton (active pelvic orthosis). The method outputs the recognition decisions at each extreme point of the hip joint angles purely relying on the integrated inertial sensors. Compared with the related studies, our approach enables calibrations and recognition without additional sensors on the feet. We validated the method by measuring four locomotion modes and eight locomotion transitions on three able-bodied subjects wearing an active pelvic orthosis (APO). The average recognition accuracy was 92.46% for intrasubject crossvalidation and 93.16% for intersubject crossvalidation. The average time delay during the transitions was 1897.9 ms (28.95% one gait cycle). The results were at the same level as the related studies. On the other side, the study is limited in the small sample size of the subjects, and the results are preliminary. Future efforts will be paid on more extensive evaluations in practical applications.

scholarly journals Contribution to the method for determining femoral neck axis

2014 ◽  
Vol 142 (3-4) ◽  
pp. 178-183 ◽  
Author(s):  
Zoran Andjelkovic ◽  
Desimir Mladenovic ◽  
Zoran Vukasinovic ◽  
Stojanka Arsic ◽  
Milorad Mitkovic ◽  
...  
Keyword(s):  
Femoral Head ◽  
Femoral Neck ◽  
Small Sample Size ◽  
Alpha Angle ◽  
Head Rotation ◽  
Small Sample ◽  
Femoral Neck Axis ◽  
Rotation Center ◽  
Head Translation ◽  
Head Neck

Introduction. Femoral neck axis plotting is of great significance in measuring parameters that define femoral head-neck junction sphericity in the group of patients with the femoroacetabular impingement. Literature methods of femoral neck axis determination have weaknesses associated with the risk of obtaining inaccurate values of certain parameters. Objective. Method of plotting of the femoral neck axis by two parallel lines that belong to the medial quarter of the femoral neck is proposed. Method was tested on the anatomic specimens and the respective radiograms. Methods. A total of 31 anatomic specimens of the proximal femur and respective radiographs were used, on which three axes of the femoral neck were plotted; accordingly, alpha angle value was determined and tested with corresponding parametric tests, with the measurement error of less than 5% and the strength of the applied tests of 80%. Results. Alpha angle values obtained by plotting femoral neck axis using the literature and methods we have proposed were not significantly different in our series, and, in more than a half of the specimens, the two axes overlapped each other. Conclusion. The advantage of the proposed method does not depend on the position of the femoral head rotation center in relation to the femoral neck, which favors proposed method for measuring the angles of femoral head sphericity in patients with the femoral head translation. Disadvantage of the study is a small sample size for valid conclusions about the applicability of this method in clinical practice.

Anguilliform locomotion in an elongate salamander (Siren intermedia): effects of speed on axial undulatory movements

1997 ◽  
Vol 200 (4) ◽  
pp. 767-784 ◽  
Author(s):  
G Gillis
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Lateral Displacement ◽  
Small Sample Size ◽  
Body Position ◽  
Orientation Angle ◽  
Small Sample ◽  
The Body ◽  
Lateral Velocity ◽  
Forward Movement

Many workers interested in the mechanics and kinematics of undulatory aquatic locomotion have examined swimming in fishes that use a carangiform or subcarangiform mode. Few empirical data exist describing and quantifying the movements of elongate animals using an anguilliform mode of swimming. Using high-speed video, I examine the axial undulatory kinematics of an elongate salamander, Siren intermedia, in order to provide data on how patterns of movement during swimming vary with body position and swimming speed. In addition, swimming kinematics are compared with those of other elongate vertebrates to assess the similarity of undulatory movements within the anguilliform locomotor mode. In Siren, most kinematic patterns vary with longitudinal position. Tailbeat period and frequency, stride length, Froude efficiency and the lateral velocity and angle of attack of tail segments all vary significantly with swimming speed. Although swimming speed does not show a statistically significant effect on kinematic variables such as maximum undulatory amplitude (which increases non-linearly along the body), intervertebral flexion and path angle, examination of the data suggests that speed probably has subtle and site-specific effects on these variables which are not detected here owing to the small sample size. Maximum lateral displacement and flexion do not coincide in time within a given tailbeat cycle. Furthermore, the maximum orientation (angle with respect to the animal's direction of forward movement) and lateral velocity of tail segments also do not coincide in time. Comparison of undulatory movements among diverse anguilliform swimmers suggests substantial variation across taxa in parameters such as tailbeat amplitude and in the relationship between tailbeat frequency and swimming speed. This variation is probably due, in part, to external morphological differences in the shape of the trunk and tail among these taxa.

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