• Volume 36,Issue 6,2021 Table of Contents
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      2021, 36(6).

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      2021, 36(6).

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    • Contents from Issue 1 to 6 of Volume 36, 2021, Journal of Medical Biomechanics

      2021, 36(6).

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    • >Expert forum
    • Characteristics Analysis on Science Fund Application and Suggestions for Development of Biomechanics

      2021, 36(6):835-840.

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      Abstract:This paper introduces the application for National Natural Science Foundation of China (NSFC) projects on mechanical sciences in the year 2021, analyses the characteristics of fund application in all branches of mechanics, especially biomechanics, points out some problems existing in fund application, and proposes several suggestions about the interdisciplinary research and development on biomechanics.

    • >Original Articles
    • Mechanical Characterization and Numerical Simulation of the Ti6Al4V Porous Scaffolds Based on Weaire-Phelan Structure

      2021, 36(6):841-848.

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      Abstract:Objective To study mechanical properties of porous scaffolds with lattice Weaire-Phelan (LWP) structure and precisely simulate the whole process of compression test using finite element method. Methods The Ti6Al4V (TC4) porous scaffolds with different porosities were manufactured by selective laser melting (SLM) technology, and their mechanical properties were measured by uniaxial compressive tests, and compared with those of human bones and porous scaffolds with other cellular structures. Four types of material models were verified for their effects on the simulation of porous scaffold compression. Results LWP samples presented the elastic modulus close to that of human cancellous bone and significantly higher yield strength than that of cortical bone in most parts of human body. Compared with other scaffold structures, LWP samples exhibited the lowest elastic modulus and highest yield strength. The simulated results derived from the proposed material model in this study, namely, Johnson-Cook constitutive model and failure model based on dynamic geometric strain (JCDG), were proved very consistent with the experimental data. Conclusions LWP scaffolds as the bone repair biomaterials exhibite more excellent mechanical properties than the scaffolds with other structures. JCDG is more beneficial for establishing the reasonable simulation model of porous scaffolds compression, compared with other reported material models.

    • Biomechanical Analysis on Different Methods of Growing Rod Fixation for Early Onset Scoliosis

      2021, 36(6):849-854.

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      Abstract:Objective To study the effects of selecting different fixing segments on biomechanical characteristics of the spine during the treatment of early onset scoliosis(EOS) by growing rod technique. Methods By using finite element method, four spine models (C6-S1 segments) fixed by growing rod were established: preoperative model, T1-L4 fixed model, T2-L4 fixed model, T3-L4 fixed model. Then 7 N·m torque load and 1 rad angular displacement load were applied on superior surface of C6 segment to analyze biomechanical characteristics for adjacent structure of the fixed vertebral body. Results The whole spinal range of motion (ROM) decreased significantly after operation. When the T2-L4 segment was fixed, the spine activity was mostly restricted, the compensatory activity of adjacent vertebrae increased significantly, and the intervertebral disc stress increased significantly. Conclusions When T2 segment is selected as the upper instrumented segment, the risk of proximal junctional kyphosis and spinal degeneration is the highest, which should be avoided in clinical surgery.

    • Local Optimization Design of Three-Dimensional Printed Scoliosis Orthosis Based on Finite Element Analysis

      2021, 36(6):855-861.

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      Abstract:Objective To optimize the design of three-dimensional (3D) printed scoliosis orthosis with computer-aided design (CAD), so as to achieve the advantages of good mechanical strength and lightweight model. Methods The body contour of a volunteer was scanned by a hand-held 3D scanner, then the body surface model of the volunteer was established. According to the three-point bending principles, traction and load-free principle, the body surface model was modified, and the pressure area and release area were designed. The model of scoliosis orthosis was then designed preliminarily. Comparative study on local optimization of hollow combinations with 32 different sizes were conducted using orthogonal experimental method. According to the optimization results, the model of scoliosis orthosis was hollowed out and biomechanically analyzed. The stress distributions of the 3D printed hollow scoliosis orthosis were compared, and its optimization effect was verified. Results By adopting the optimal design of local hollowing-out with 9 mm-radius and 23 mm-spacing circular hole (40% local weight loss), the 3D printed scoliosis orthosis with lighter weight, better air permeability and sufficient strength could be obtained. Conclusions Based on finite element biomechanical analysis, by adopting local hollow optimization design of circular hole at non-stress area, the 3D printed scoliosis orthosis can achieve the advantages of less printing materials and increased air permeability, and ultimately improve the wearing comfort and compliance of patients.

    • Hemodynamic Study on Non-Newtonian Properties of Fontan Procedure

      2021, 36(6):862-868.

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      Abstract:Objective To investigate the effects of non-Newtonian properties on hemodynamic characteristics of Fontan procedure in computational simulation. Methods A Fontan vascular model was reconstructed based on patient-specific medical images. The boundary conditions were set according to velocity profiles measured by real-time echocardiography. The Newtonian model and two non-Newtonian (Casson and Carreau) models were applied to analyze the hemodynamic parameters, including flow ratio (FR), energy loss (EL), wall shear stress (WSS) as well as non-Newtonian importance factor, so as to compare flow differences between the Newtonian model and non-Newtonian models. Results The rheological models had small effects on the FR. The EL of non-Newtonian models was higher than that of the Newtonian model, and the EL of Casson model was the highest. Flow recirculation and flow disturbance accompanied with low WSS were observed in inferior vena cava (IVC). At low inflow velocity, flow disturbance in IVC of Newtonian model was more obvious. The calculations of non-Newtonian importance factor suggested significant non-Newtonian viscosity in IVC. Conclusions Non-Newtonian viscosity is significant in IVC where low velocity and flow recirculation are observed. Non-Newtonian properties of the blood should be considered in patient-specific hemodynamic simulation of Fontan procedure.

    • Numerical Analysis on Adaptability of Valve Leaflets after Single Valve Replacement in Children

      2021, 36(6):869-876.

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      Abstract:Objective To explore the biomechanical mechanism of aortic insufficiency (AI) after single aortic valve replacement (SAVR) in children and propose the corresponding countermeasures. Methods The idealized aortic valve model and postoperative growth model were constructed. By changing the length of leaflet free edge, leaflet height as well as improving the design with a concave structure, the effects of different structure dimensions on movement synchronization and closing performance of the aortic valve after surgery were compared. Results The closure of the replacement leaflet lagged behind the autologous leaflet, which fitted 2 mm below free edge of the replacement leaflet. AI occurred 6 years after operation. Increasing leaflet height could not improve the postoperative effect and would increase the maximum stress of the leaflet. Increasing free edge length by 10% could improve the postoperative outcomes, while increasing free edge length by 15% would cause the leaflet to be too long, hence resulting in a poor fit of the aortic valve. Compared with the traditional structure, the concave structure was more beneficial for closing performance of the aortic valve, and it could effectively reduce the maximum stress by 20% with the best effect. Conclusions The leaflet movement will be out of synchronization after SAVR, the point of convergence will be shifted, and AI will appear 6 years after surgery. It is recommended to use a concave structure with free edge length increased by 10%, while increasing leaflet height is not recommended.

    • The Influence of Hydronephrosis with Different Degrees on Urodynamics of Renal Pelvis: A Model Study

      2021, 36(6):877-882.

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      Abstract:Objective To study urodynamic changes of urine at different degrees of hydronephrosis based on computational fluid dynamics (CFD) method, so as evaluate the influence of hydronephrosis degree on kidneys’ ability to discharge stones. Methods Twelve models, including the branched pelvis Model A (normal hydronephrosis A1, mild hydronephrosis A2, medium hydronephrosis A3, severe hydronephrosis A4 models), mature ampullary pelvis Model B (normal hydronephrosis B1, mild hydronephrosis B2, medium hydronephrosis B3, severe hydronephrosis B4 models), and embryo pot abdominal pelvis Model C (normal hydronephrosis C1, mild hydronephrosis C2, medium hydronephrosis C3, severe hydronephrosis C4 models) were established. The urine flow velocity and velocity vector at the neck of the kidney, the outlet of the renal pelvis were calculated by CFD method. Results As the degree of hydronephrosis increased, the flow velocity of urine at the neck of the kidney and the outlet of the renal pelvis decreased. The urinary shearing force of the stones and the kidney’s ability to discharge stones gradually decreased, whereas the circulatory stagnation zone and the velocity boundary layer in kidney aggregate system gradually increased. Conclusions Hydronephrosis can cause changes in urodynamics of the urine. Therefore, the effect of hydronephrosis with different degrees on the patient’s ability to discharge stones after surgery should be fully considered, so as to choose an appropriate treatment method for kidney stones in clinic.

    • Design and Experimental Study on Flexible Articulation of Electric Stapler

      2021, 36(6):883-889.

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      Abstract:Objective To design a notched flexible articulation applied to electric stapler and study its turning performance. Methods The notched flexible articulation was designed and modeled. The kinematics and statics models of the articulation were established for simulation calculations. The stress, deflection angle, top displacement and driving force of the articulation with 3 different turning structures were studied under equal and variable stiffness of symmetrical notches by using finite element simulation. An experimental platform for performance test of the turning structure was built to verify the simulation results and the model. Results The theoretical model of the turning structure in bending process was basically consistent with the experimental results. With the optimization of symmetrical notch stiffness, the maximum stress of the articulation with variable stiffness was reduced by 20.64% and 39.20%, respectively. The articulation with variable stiffness required the smallest tensile force during bending, which was 33.41% lower than that of the articulation with equal stiffness, and the tip displacement (30.8 mm) along the bending plane was the smallest. The maximum deflection angle for the articulation with 3 different turning structures all could reach 90°. Conclusions The kinematics and statics models of the articulation can be used for the calculation of its tensile force and position changes. The turning performance of the articulation with variable stiffness using symmetrical notch is better than that with equal stiffness. The notched flexible articulation meets the design requirements and the turning needs of electric stapler.

    • Effects of Different Implant Design Parameters on Mandibular Tooth Implantation

      2021, 36(6):890-895.

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      Abstract:Objective To establish the implant-mandible model with different design parameters, observe stress distributions on the implant and surrounding bone, and analyze the influence of different design parameters on dental implant of the mandible. Methods Eight implant models were designed based on structural characteristic parameters (implant diameter, thread depth, height of abutment through gingiva, thread shape), and assembly of the mandibular model was performed respectively. The models were applied with static 150 N vertical and oblique 45° loads, so as to analyze peak von Mises stress of the implant and bone tissues and explore the structural parameter variables of implant most sensitive to peak von Mises stress. Results The peak stress of the mandible was larger under inclined load than that under vertical load. Implant diameter was the key factor affecting the peak von Mises stress of cortical bone, while thread depth was the key factor affecting the peak von Mises stress of cancellous bone. The peak von Mises stress was also affected by the height of abutment through gingiva, but the effect was not as significant as thread depth and implant diameter. Thread shape had little effect on the peak von Mises stress of the mandible. Conclusions Different implant design parameters can affect the peak stress of different tissues of the mandible, so it is necessary to carefully consider the selection of implant parameters for personalized implants. This study can provide theoretical guidance for structural parameter design of oral implants and provide references for accurate prediction of oral implants.

    • A Continuum Constitutive Model of skeletal Muscle at Variable Strain Rate

      2021, 36(6):896-902.

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      Abstract:Objective Aiming at the problem that mechanical properties for the continuum of muscle tissues cannot be considered in active and passive behaviors of different structurally coupled muscles, a method of passive and active coupling in the same constitutive equation was proposed to construct ahyperelastic active and passive constitutive model of skeletal muscle continuum. Methods In order to calibrate parameters of the passive constitutive model, the uniaxial tensile experiment method and conditions were given, and through theoretical derivation, the specific method of using experimental data to solve the passive model parameters was introduced. In order to verify effectiveness of the active model, the model was verified with an example. Results The curves predicted by the model were in good agreement with the experimental output stress-stretch ratio curves. At the same strain, the maximum error of passive stress and total stress were only 20 kPa and 40 kPa. Conclusions The continuum hyperelastic constitutive model can better simulate active and passive behavior of skeletal muscles, which is beneficial for modeling and simulation of human muscles in further study.

    • Experimental Study on Separation of Fetal Nucleated Red Blood Cell from the Whole Blood Using Microfluidic Chip

      2021, 36(6):903-909.

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      Abstract:Objective To seperate fetal nucleated red blood cells (fNRBCs) from the whole maternal peripheral blood effectively by designing a circular channel microfluidic chip. Methods A microfluidic chip is designed by utilizing the margination in blood flow and the specific adhesion characteristics of immuno-agent anti-CD147. With the whole umbilical cord blood, the effects of different shear forces on the enrichment of fNRBCs was studied by immunofluorescence counting. Results Increasing shear rate in microfluidic chip could improve the number of captured fNRBCs compared with the static adhesion. With the increase of shear rate of blood flow, the number of the captured cells increased at first, and then decreased. Conclusions The use of microfluid chip can effectively seperate fNRBCs from the whole blood. The results provide an experimental reference for the non-invasive prenatal diagnosis research and the exploration on the mechanism of fetal cell migration.

    • Effects of Perfusion Velocity on Suspended Cells in Microchannels

      2021, 36(6):910-915.

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      Abstract:Objective To establish a finite element model of cell perfusion culture, and study the effect of different perfusion speeds on the movement of suspended cells. Methods The two-dimensional (2D) model of cell and microchannels was established using COMSOL Multiphysics and meshed. Three groups were established according to the perfusion speed, namely, u0=0.196 mm/s, u1=0.117 mm/s, u2=0.04 mm/s. The fluid-structure interaction module was used for calculation. Results The flow field distribution in the microchannel was relatively uniform. During the equal period of time, the ratio of cell suspension perfusion speed was u0∶u1∶u2=5∶3∶1, and the ratio of cell displacement in the microchannel was D0∶D1∶D2=4.1∶ 2.9∶1. When the speed was proportional, the displacement of cells also roughly followed the corresponding proportional change. With the increase of perfusion speed, stress concentration in cells during movement would occur. The stress and fluid shear force (FSS) of cells during movement were within the safe value range, and cell destruction would not occur. Conclusions The suspended cells can enter into the microchannel without injury at a certain perfusion speed. Perfusion techniques can be used in cell implantation of in vitro tissue engineering products.

    • Characteristics of Different Tai Chi Step Types Based on AnyBody Simulation

      2021, 36(6):916-922.

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      Abstract:太极拳; AnyBody仿真; 下肢; 动力学; 运动学

    • Static Finite Element Analysis on Hip Disarticulation Prosthesis Socket-Residual Limb in Stance Phase

      2021, 36(6):923-928.

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      Abstract:Objective To study mechanical properties of the interface between hip residual limb and hip socket during the stance phase by using the finite element analysis (FEA) method, so as to provide the theoretical basis for structure optimization and design of hip socket, as well as the research basis for comfort evaluation of hip socket. Methods According to CT scan images of the patient’s residual limb, the model of bone, soft tissues and socket was reconstructed by reverse modeling. The distribution of normal stress and shear stress on the interface between hip residual limb and hip socket was analyzed and a pressure acquisition module system was designed to verify the stress distribution condition. Results The interfacial stress between hip residual limb and hip socket was mainly distributed in the waist and the bottom of the residual limb, and the interfacial stress was more evenly distributed in the rest of the residual limb. The results of finite element calculation were in good agreement with the system measurement results of pressure acquisition module. Conclusions In order to improve force transfer and safety and comfort of the hip socket, it is necessary to fully consider stress condition of the waist and bottom of the residual limb, as well as the coordination degree between residual limb and hip socket.

    • Experimental Study of Hemilaminectomy, Total Laminectomy and Recapping laminoplasty of Cervical Spine in Sheep

      2021, 36(6):929-934.

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      Abstract:Objective To study the effect of hemilaminectomy, total laminectomyand recapping laminoplasty on stability of the cervical spine. Methods Fourteen fresh adult sheep cervical spine specimens were divided into two groups, with 7 cases in each group. Each specimen was applied with a pure moment load of 3.0 N·m under flexion/extension, left/right lateral bending, and left/right axial rotation. The range of motion (ROM) and neutral zone (NZ) of specimens were measured. In the first group, the ROMs and NZs of the specimens were measured and compared under the intact state, C5 hemilaminectomy state and C4-6 hemilaminectomy state respectively. In the second group, the ROMs and NZs of specimens under the intact state, C4-6 total laminectomy state and C4-6 recapping laminoplasty state were measured and compared. Results There were no significant differences in ROMs and NZs between C5 hemilaminectomy state and C4-6 hemilaminectomy state compared with the intact state (P<0.05). Compared with the intact state, ROMs of the specimens were significantly increased during flexion and extension under C4-6 laminectomy state and C4-6 recapping laminoplasty state (P<0.05). In addition, compared with the C4-6 laminectomy state, ROMs of the specimen were significantly decreased only during extension unde C4-6 recapping laminoplasty state (P<0.05), while no significant differences were found in ROMs between total laminectomy and laminoplasty under other loads. Conclusions With hemilaminectomy, ROMs and NZs of the cervical spine did not increase significantly, and stability of the cervical spine was not affected. With C4-6 total laminectomy, ROMs and NZs during flexion and extension increased significantly, and stability of the cervical spine was affected. Recapping laminoplasty did not significantly improve stability of the cervical spine with total laminectomy.

    • Degradation Behavior and Mechanical Properties of Magnesium Alloy Plate in vivo

      2021, 36(6):935-939.

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      Abstract:Objective To study the degradation behavior and mechanical properties of magnesium alloy plate on treatment of tibial fracture in New Zealand rabbits. Methods Thirty-six adult New Zealand rabbits were randomly divided into experimental group (magnesium alloy bone plate group, n=18) and control group (titanium alloy bone plate group, n=18). Tibial fractures in experimental group and control group were fixed with magnesium alloy bone plate and titanium alloy bone plate, respectively. After operation, X-ray, scanning electron microscopy, energy spectrum analysis, weight loss test and four-point bending test were performed in each group to analyze the degradation behavior and mechanical properties of magnesium alloy plate after tibial fracture treatment. Results Magnesium alloy bone plate could be degraded gradually in vivo. The degradation of magnesium alloy bone plate was deepened gradually with the implantation time, and the surface was corroded uniformly. The mechanical properties of magnesium alloy bone plate decreased gradually with the degradation in vivo. Conclusions Magnesium alloy bone plate can degrade gradually with fracture healing in vivo, and its mechanical properties gradually decline, but it can still meet the requirements of fracture internal fixation, and is a kind of good new degradable orthopedic implant material.

    • Reliability Study on Erector Spinae Stiffness of Adults Using Muscle Stiffness Test Device

      2021, 36(6):940-944.

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      Abstract:肌肉硬度; 竖脊肌; 信度; 康复训练

    • Evaluation of Optimal Gravity Center Position of Backpack in Half-Squat Parachuting Landing

      2021, 36(6):945-950.

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      Abstract:Objective To study effects of backpack gravity center position on kinetics and kinematics of lower-extremity joints in parachuting landing and evaluate the injuries. Methods Seven participants performed parachuting landing with backpack gravity center on three positions: low-back (position 1), upper-back (position 2) and abdomen (position 3). Results The peak vertical ground reaction force (GRF) with backpack on position 2 was significantly lower than that on position 1. The joint moment on sagittal plane of the hip with backpack on position 2 was significantly higher than that on position 1 and position 3. The joint energy absorption of the hip with backpack on position 2 was significantly higher than that on position 1. The angular displacement of the hip on sagittal plane with backpack on position 2 was significantly higher than that on position 1 and was significantly lower than that on position 3. The angular velocity of the hip on sagittal plane with backpack on position 2 was significantly lower than that on position 3. Conclusions Different positions of backpack gravity center could significantly influence kinetic and kinematic parameters of the hip. Backpack gravity center on upper-back position could decrease the lower-extremity injuries. The results can provide evidences for evaluating backpack gravity center and decreasing injuries in parachuting landing.

    • The Influence of Arch Difference on Dynamic and Static Foot-Ankle Function

      2021, 36(6):951-956.

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      Abstract:Objective To evaluate the difference of foot-ankle function for subjects with different foot types from both dynamic and static aspects by means of sports biomechanics, so as to provide theoretical support and references for the study of foot-ankle movement. Methods According to the arch index, 65 subjects were divided into three groups: flat foot, low arch foot and normal foot. One-way ANOVA was used to analyze the difference of static and dynamic foot-ankle function indexes among the three groups. Results In terms of static foot-ankle function, the malleolar valgus flexibility (MVF) of normal foot and ankle was significantly higher than that of low arch foot and flat foot (P<0.05), while in terms of arch height flexibility (AHF), the effect of weight bearing on normal foot was smaller than that of flat foot (P<0.05), but there was no significant difference in transverse arch flexibility (TAF) among the three groups. In terms of dynamic foot-ankle function, the force offset amplitude and time of normal foot at buffer stage were higher than those of the other two groups (P<0.05), and at transition stage, the transition time of normal foot was significantly lower than that of low arch foot and flat foot (P<0.05). At pedal-extension stage, the pedal-extension time and speed of normal foot were significantly higher than those of flat foot (P<0.05). Conclusions The posture maintenance ability and longitudinal arch shape maintenance ability of low arch foot and flat foot are worse than those of normal foot with the load increasing, and the arch rigidity and plantar elasticity of low arch foot and flat foot are worse than those of normal foot, and normal foot shows better load-bearing cushioning ability, elastic-to-rigid transition ability and pedal extension efficiency during walking. A systematic and comprehensive evaluation system is of great significance to the prediction of foot-ankle injury risk and the evaluation of sports ability.

    • Characteristics of Short-Term Static Balance in Obese Children

      2021, 36(6):957-962.

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      Abstract:Objective To explore the characteristics of short-term static balance of obese children by comparing the excursion of center of pressure (COP) in obese and non-obese children under six kinds of standing circumstances. Methods By using the Footscan balance plate system, parameters of COP excursion for 47 obese children and 50 non-obese children standing on both feet or single foot with eyes open or eyes closed for 10 seconds were obtained, respectively. Results The maximum COP displacement in anterior-posterior direction of obese children was significantly greater than that of non-obese children during standing on both feet with eyes closed. During standing on left foot with eyes open, the sway velocity of obese boys was significantly lower than that of non-obese boys; the maximum COP displacement in medial-lateral direction of obese boys was significantly lower than that of non-obese boys and the maximum displacement of COP in medial-lateral direction of obese girls was significantly greater than that of non-obese girls. The sway velocity of boys was significantly greater than that of girls during standing on left foot with eyes closed. Conclusions In short period of time, the static balance of obese children in anterior-posterior direction was worse than that of non-obese children during standing on both feet with eyes closed. Obesity had different impacts on static balance of different genders. The performance of static balance for obese boys was better than that of non-obese boys, while the performance of static balance for obese girls was worse than that of non-obese girls during standing on left foot with eyes open. Girls had a better static balance performance than boys during standing on left foot with eyes closed. There were no significant differences in static balance performance between boys and girls under the other circumstances. As static balance of children is affected by obesity and gender, it is suggested that different methods of losing weight should be considered for obese children of different genders.

    • The Effect of Trunk Motion Control on Biomechanical Parameters of Knee During Landing

      2021, 36(6):963-969.

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      Abstract:Objective To determine the effect of trunk motion control on knee biomechanics during single-leg landing. Methods Twenty male healthy basketball players were recruited. The kinematics, kinetics parameters and surface electromyogram (EMG) of knee joints under trunk motion control during single-leg landing were studied by using Vicon motion Analysis system, Kistler force platform and Noraxon surface EMG system. Results Compared with natural landing, there were significant differences in flexion angle at initial contact moment, peak flexion angle and peak flexion moment during deeply inspiratory landing and landing with a stick, and a significantly larger flexion angle at initial contact moment, a larger peak flexion angle and smaller peak flexion moment were also found. Compared with natural landing, there was no statistical difference in peak valgus angle and peak valgus moment, as well as EMG activity of hamstrings, quadriceps muscles of the knee during deeply inspiratory landing and landing with a stick. Conclusions Deeply inspiratory landing or landing with a stick reduce the risk of anterior cruciate ligament (ACL) injury, and the results provide the theoretical basis for prevention of ACL injuries in basketball players during landing.

    • Screening of IGF-1, NOS, FGF23 and Sclerost-Targeted Mechanoresponsive MicroRNAs

      2021, 36(6):970-977.

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      Abstract:Objective To screen the secretory factor-related, mechanoresponsive microRNAs (miRNA) of osteocytes. Methods Cyclic mechanical tensile strain (ε=2.5,f=0.5 Hz) was applied to osteocytes and osteoblasts cultured in vitro respectively, and the differentially expressed miRNAs only in the osteocytes were screened out by using miRNA chip. Through bioinformatics technology, in these differentially expressed miRNAs, the target genes of secretory factors including insulin-like growth factor-1(IGF-1), nitric oxide synthesase (NOS), fibroblast growth factor 23 (FGF23) and sclerostin (SOST) were further screened out. Then the selected miRNAs were compared with the biochip detected, differentially expressed miRNAs in femur bone of the mice which were trained on treadmill, and four of these miRNAs were randomly selected for quantitative PCR verification. Results For the 77 differentially expressed miRNAs only in the mechanically strained osteocytes in vitro, 22 miRNAs whose target genes were the 4 secreted factors (IGF-1, NOS, FGF23 and SOST), were screened out. Moreover, a total of 11 miRNAs in the 22 miRNAs were differentially expressed in femur bone of the treadmill trained mice with the same trend as those in osteocytes in vitro, and the randomly selected miR-361-3p, miR-3082-5p, miR-6348 and miR-706 were confirmed to be differentially expressed with the same trend in femur bone and osteocytes. Conclusions These mechanoresponsive miRNAs differentially expressed only in osteocytes, such as miR-361-3p, miR-3082-5p, miR-6348 and miR-706, probably influence osteoblastic differentiation or bone metabolism through regulating the secretory factors.

    • Effects of Moderate Intensity Exercise Training Combined with Xianlinggubao Capsule on Bone Metabolism in Ovariectomized Rats

      2021, 36(6):978-983.

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      Abstract:Objective To observe the effects of moderate intensity exercise training combined with Xianlinggubao capsule on bone mineral density (BMD), bone metabolism and femoral biomechanics of ovariectomized rats, so as to provide lab references for osteoporosis prevention. Methods Fifty female SD rats were randomly divided into 5 groups, 10 rats in each group. Group A was the normal control; Group B was given 1 mL normal saline by gavage after ovariectomy for one week; Group C was given moderate intensity exercise training (exercise speed was 20 m/min, lasting for 60 min per day, continuous 5 days per week); Group D was given 1 mL Xianlinggubao capsule [0.4 g/(kg · d)] after 1-week ovariectomy; Group E was was given both 1 mL Xianlinggubao capsule and moderate intensity exercise training after 1-week ovariectomy. After 8 weeks of continuous treatment, blood biochemical indexes, BMD, micro CT and biomechanics of the femur and L5 vertebral body were detected. Results Compared with group B, the blood biochemical indexes of Group C-E were improved in varying degrees, the BMD of L5 vertebral body and femur were increased, the bone volume fraction, trabecular number and trabecular thickness of femur (or L5 vertebral body) were increased, the trabecular space and structural model index were decreased, the maximum load, maximum deflection and maximum stress of L5 vertebral body were increased, and the maximum stress of femur was increased. The maximum load, elastic load, elastic deflection, elastic modulus, elastic stress, maximum stress and elastic deflection increased, and the effect of Group E was the most obvious. Conclusions Moderate intensity exercise training combined with Xianlinggubao capsule can improve BMD, bone metabolism and bone microstructure, and improve bone mechanical properties of ovariectomized rats.

    • Progress of Big Data Analysis in Gait Biomechanics

      2021, 36(6):984-989.

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      Abstract:Objective To study the research progress of big data analysis in gait biomechanics. Methods Based on the scientific and technological literature related to big data analysis in gait biomechanics during the year 2011-2020 as the research object, content analysis method was used to analyze and discuss from four aspects, including topic structure, hierarchy level, model type and analysis technology. On this basis, the future research of gait biomechanics big data analysis was prospected. Results The application of big data analysis in gait biomechanics mainly involves five research directions, namely, intervention and rehabilitation, exercise training, prosthesis design and evaluation, understanding of etiology and diagnosis, understanding of human movement characteristics. Big data analysis in gait biomechanics is divided into three levels, of which descriptive analysis is the most used type, accounting for about 41%. The models and specific techniques of big data analysis in gait biomechanics field were reviewed. Topological data analysis is a promising big data exploration tool for future research. Conclusions Big data technology has great potential in gait biomechanics and clinical medicine research.

    • Analysis on Published Papers of Journal of Medical Biomechanics during the Year 2015-2019

      2021, 36(6):990-994.

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      Abstract:To analyze the articles published in Journal of Medical Biomechanics during the year 2015-2019, so as to make references for improving the quality of the journal. Methods Based on data published by Chinese S&T Journal Citation Reports, the citation index and source index of the journal during the year 2015-2019 were collected for statistic analysis. Results During the year 2015-2019, the journal’s total citations, impact factors, number of citing journals, number of source papers, average citations were steadily increased. Eighty-four percent of the published papers were funded, with a wide range of subject distributions. Conclusions The 5-year academic impact of the journal has been improving. To expand the academic impact, the journal should make further efforts in giving full play to the role of the Editorial Committee, shortening the publication cycle, as well as strengthening propaganda and promotion of the journal.

    • >Review Articles
    • Current Status and Prospects of Non-Invasive Central Arterial Pressure Measurement

      2021, 36(6):995-1001.

      Abstract (114) HTML (0) PDF 2.20 M (1) Comment (0) Favorites

      Abstract:Cardiovascular disease is one of the important factors that threaten the health of residents, ranking the first among various causes of death, so the monitoring and diagnosis of human cardiovascular health is particularly important. Compared with traditional brachial artery pressure, central arterial pressure (CAP) has a higher correlation with the occurrence of many cardiovascular events. The measurement of CAP can more accurately reflect the real situation of human blood pressure, and provide an important basis for diagnosis and disease prevention. Therefore, the realization of high-precision, high-generalization ability and low-cost non-invasive measurement of CAP has always been the research focus in this field. This article combines the relevant literature in China and abroad to summarize the current status of CPA measurement, introduces related research progress from two aspects, namely parameter measurement and waveform measurement, and discusses the characteristics of the existing methods and the future development.

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