ABSTRACT
BACKGROUND:The finite element analysis used to study the biomechanical properties of foot structure contributes to overcome the disadvantages of traditional mechanical analysis of specimens. OBJECTIVE:To summarize some representative finite element models of the foot and review the establishment methods of finite element models of the foot with biomechanical properties. METHODS:A computer-based online search was conducted in CNKI, Wanfang and PubMed databases by using the key words of“finite element model, biomechanic, foot structure”from 1999 to 2015. The language was limited to both Chinese and English. Establishment methods of finite element models of the foot structure containing obtaining of model establishment data, establishment of solid model, setting methods of properties of model materials. The application of finite element analysis of the foot structure in sports biomechanics and medical orthotics was summarized to point the characteristics and disadvantages of finite element analysis application in biomechanics. RESULTS AND CONCLUSION:An increasing number of studies on foot biomechanics provide the platform for finite element analysis of the foot applied in biomechanical analysis. Many key technologies, including self-adaption image segmentation method, hexahedron grid product method and establishment of finite element models with various materials have to be utilized to converse the medical images into digital models of finite element analysis during establishment of finite element models. Results of model establishment may be affected by limitation conditions, accuracy of image col ection, calculation results of finite element analysis. The reliability of finite element models can be increased by modify technologies and verification methods.
ABSTRACT
BACKGROUND: Kinematics studies the movement of the objects using a method of geometry, with strength and quality not taken into consideration; Kinetics major studies the force of people acting on objects and its relationship with the movement of objects. OBJECTIVE: Through an introduction to kinematics and kinetics research equipment, this study was aimed to lead to the current status of kinematics and kinetics, to provide for experimental basis for the research of new equipment and gait experiments. METHODS: Taking "gait, kinetics, kinematics" in English for the search terms, Pubmed database (1999-01/2009-06)was retrieved. Taking "gait, kinematics, kinetics" in Chinese for the search terms, CNKI database (1999-01/2009-06) was searched. Literatures were limited to English and Chinese languages. The kinematics and kinetics research equipment regarding the gait were included, while other kinematics and kinetics experiments were excluded, also outdated and repetitive researches were excluded. RESULTS AND CONCLUSION: Totally 2 367 literature were obtained from the computer screen, and 33 documents of them were involved for analysis according to the inclusion and exclusion criteria, in case of gait analysis method, at home and abroad scholars have carried out extensive studies although the content are quite different, they used identical instruments and methods in the testing of gait, in spite of photography or video recording were applied to calculate and measure kinematic parameters, the force platform was all used to record kinetic parameters. Also there are a small number of studies using the distribution of plantar pressure to measure more precise foot-ground pressure distribution, and then proceed to a comprehensive statistical analysis. Kinetics and kinematics gait analysis is applied not only in rehabilitation medicine, but also widely in athletics sports and the related footwear manufactures, the commonly used method is the plane fixed-point photograph and force platform analysis.
ABSTRACT
BACKGROUND:The comfortable shoes can absorb or reduce the impact force from the ground. Is the damped system is absent in shoes to relieve the impulse,the feet will be extremely tired,even damage the human knee joint,waist,back and brain. OBJECTIVE:To measure the changes of human plantar pressure by different sole hardness through the measurement system of plantar pressure. DESIGN,TIME AND SETTING:An observation experiment was performed in the Shanghai University of Sport between December 2008 and February 2009.PARTICIPANTS:Six volunteers wearing the experimental designed shoes were recruited from Nanjing Institute of Physical Education.METHODS:Three pairs of experimental shoes weighing 103 g were measured with shore hardness tester,as 51,62 and 69 hardness values. Accordingly they were named soft shoes,medium hardness shoes and hard shoes. The subjects were asked to do a 60-minute walk test at the speed of 2 m/s on the running platform with the experimental designed shoes,and they were determined using the insole plantar pressure measurement system of German's Novel style series of Emed-pedar.MAIN OUTCOME MEASURE:The pressure,contact area and impulse in the sole of foot.RESULTS:With the increase in hardness soles,the pressure of center plantar was shown to move from the medial first metatarsal outwards by turns. Compared with barefoot walking,the trail length of the center plantar was prolonged in subjects with medium hardness shoes and hard shoes,while shortened in subjects with soft shoes. The total pressure when you walked with soft shoes and medium hardness shoes were reduced than barefoot walking,and the pressure of walking phase wearing these two types of shoes were also reduced,while total pressure and walking phase pressure with hard shoes were both increased compared with barefoot walking. The contact area was similar between soft shoes and medium hardness shoes,but the smallest in the hard shoes. Except the increase in the initial 10 minutes,the soft shoes had no change with the medium hardness shoes. The hard shoes were firstly increased but then declined. The total impulse of medium hardness shoes was the closest to bare feet,while that of soft shoes and hard shoes were increased compared with bare foot.CONCLUSION:The plantar pressure was the greatest in the hard shoes,then medium hardness shoes and last soft shoes;the contact area was the greatest in soft shoes,then medium hardness shoes and last hard shoes;the impulse was the greatest in hard shoes,then soft shoes,and last medium hardness shoes.
ABSTRACT
BACKGROUND:The studies of plantar pressure mainly focus on barefoot,while the research regarding the effect of shoes on kinetic parameters is little.OBJECTIVE:To explore the peak value of foot plantar pressure between barefoot and wear shoes in max force,max pressure,load rate and impulse during the natural walk,and to search the parameter relationship between barefoot and with shoes.DESIGN,TIME AND SETTING:The the same body control analysis was performed at the Laboratory of Sports and Human Science of Nanjing Institute of Physical Education in October 2007 PARTICIPANTS:A random sampling method was used to selected 10 male college students from the Nanjing Institute of Physical Education which aged(21.00?2.40) years,weighing(71.53?3.16) kg,body height(176.32?2.62) cm,and foot length(25.67?0.92) cm.According to the regulation,informed consent was obtained from each participant.METHODS:Normal gait of 10 participants were measured by Foot scan7.0 plantar pressure test system,including barefoot and with shoes.MAIN OUTCOME MEASURES:The distribution of maximum force,maximum pressure,load rate and impulse.The parameter relationship between barefoot and with shoes were assessed in the study.RESULTS:The max force existed in the area of heel medial,the second metatarsal and the third metatarsal.The minimum force existed in the area of the toes 2-5 and the fifth metatarsal.The max pressure of barefoot existed in the area of the toes 2-5 and the second metatarsal and heel during walking.The load rate of heel was the highest.The max impulse existed in the second metatarsal and the third metatarsal and heel.The minimum impulse existed in the toes 2-5 and the fifth metatarsal.When wearing shoes,the max force existed in the area of the mid foot and toe1,The minimum force existed in the area of the toe 5,during walking the max pressure existed in the area of the instep.The load rate of the mid foot and heel was the highest.The max impulse existed in the mid foot.The minimum impulse existed in the fifth metatarsal.CONCLUSION:The parameters of forefoot,instep,and heel were larger than barefoot during walking,especially those of the phalanges2-5 and instep.