Yang L.,Hong Kong Polytechnic University |
Yang L.,Shanghai Gaitech Scientific Instruments Co. |
Gong H.,Hong Kong Polytechnic University |
Gong H.,Beihang University |
Zhang M.,Hong Kong Polytechnic University
Journal of Mechanics in Medicine and Biology | Year: 2012
This study focuses on the transmissibility of whole body vibration stimuli through human body in different standing postures to explore the mechanism in which vibration stimuli could be better used as a regimen for bone loss. Five volunteers were guided to stay at three standing postures and imposed of frequency-adjustable vibration stimuli on the plantar surfaces side-alternately. Motion capture system was used to acquire the vibration signals at head, pelvis, knee up, knee down and ankle, from which the transmissibility of vibration stimuli can be obtained. The results showed that transmissibility of vibration stimuli was closely correlated with frequency and skeletal sites. Transmissibility of vibration stimuli in head was much smaller than any other skeletal sites. Transmissibility in the ankle was always in the vicinity of unit one in all the three postures for the vibration stimuli applied side-alternately on the plantar surfaces of both feet. There was an obvious peak around 9 to 11 Hz in the transmissibility curves for knee joint and pelvis. In the resonant peak, transmissibility of vibration stimuli in knee joint and pelvis both exceeded unit one and reached 150%. As the frequency increased after 11 Hz, transmissibility of vibration stimuli decayed rapidly as a function of frequency and dropped to 25% at 30 Hz. This study may help to gain insight into the interaction mechanism between mechanical vibration stimuli and the responses of human musculoskeletal system. © 2012 World Scientific Publishing Company.
Hu X.-H.,Henan International Central Hospital |
Hu X.-H.,Chinese PLA 113 Hospital |
Hong X.,Institute of Forensic Science |
He B.-F.,Institute of Forensic Science |
And 3 more authors.
Yiyong Shengwu Lixue/Journal of Medical Biomechanics | Year: 2014
Objective: To build a 3D finite element model of the whole cervical spine by using Simpleware software, as well as validate and analyze the model, so as to provide a reliable model for exploring the mechanism of cervical spine injury. Methods: The 3D entity model of the whole cervical spine C1-7 was established based on CT tomography images, medical image processing software Simpleware, reverse engineering software Geomagic, which was imported to Hypermesh for meshing, adding ligaments and introducing facet joint contact relation, etc., thus to establish the finite element model of the whole cervical spine C1-7. Biomechanical properties of the cervical spine under flexion, extension, lateral bending and torsion were simulated by ANSYS. Results: The established model was proved to be accurate and reliable, and its range of motion (ROM) under flexion, extension, lateral bending and axial rotation was similar to in vitro experiment and finite element analysis results in related literatures. The stress of intervertebral disc was concentrated on the compression side of the vertebral body, and the cervical spine C4/5 was more prone to have a stress concentration. Conclusions: The finite element model of the whole cervical spine C1-7 can effectively simulate the biomechanical characteristics of the cervical vertebra, which establishes a good foundation for the follow-up studies on whiplash injury of the cervical spine. Copyright © 2014 by the Editorial Board of Journal of Medical Biomechanics.
Liu S.-Z.,Chongqing University |
Hu Z.-G.,Henan University of Science and Technology |
Zhang J.,Shanghai Gaitech Scientific Instruments Co.
Yiyong Shengwu Lixue/Journal of Medical Biomechanics | Year: 2015
Objective: To analyze the badminton athletes'dynamic responses in their lower limbs under impact loads. Methods: A human musculoskeletal model was established based on AnyBody Modeling System software and verified by measuring surface electromyography (EMG). The muscle force, joint force, joint torque of lower limbs during right Front-Court Lunge Step in badminton were studied by inverse dynamic simulation and analysis through Vicon motion capture system and force platform. Results: The musculoskeletal model was validated to be effective by EMG. During right Front-Court Lunge Step in badminton, the force peak of the hip and ankle joint in Z direction was larger than that in X and Y direction, and the force peak of the knee joint in X direction was larger than that in Y and Z direction. During buffer period, the hip joint in X, Y, Z direction showed adduction, extension and internal rotation torque, respectively, the knee joint in X, Y, Z direction showed abduction, flexion and external rotation torque, respectively, and the ankle joint in X, Y direction showed varus and plantar flexion torque, respectively. The peak torque of the hip, knee and ankle joint in X direction was significantly larger than that in Y and Z direction. Vastus lateralis, biceps femoris, anterior tibial and medial gastrocnemius played a larger role against the ground reaction, while rectus femoris, semitendinosus, soleus played a relatively smaller role against the ground reaction. Conclusions: The established musculoskeletal model in the study can provide a technical platform to analyze athletes' biomechanical properties of lower limbs under impact loads. To avoid sport injuries, more attention should be paid to the effect from ground reaction force load at touchdown instant on hip, knee and ankle joints in anteroposterior and mediolateral direction during footwork similar to Front-Court Lunge Step in badminton, and at the same time, the strength training of vastus lateralis, biceps femoris, anterior tibial and medial gastrocnemius of badminton players should not be ignored during specialized training. Copyright © 2015 by the Editorial Board of Journal of Medical Biomechanics.
Yin C.-S.,Anhui University of Science and Technology |
Sun F.,Shanghai Gaitech Scientific Instruments Co. |
He Y.,Anhui University of Science and Technology |
Shao H.-W.,Anhui University of Science and Technology
Chinese Journal of Tissue Engineering Research | Year: 2013
BACKGROUND: Anybody human modeling and simulation system is a computer-aided ergonomics and biomechanical analysis software, and it is the only software that can analyze the musculoskeletal system completely which can be used to calculate the force deformation of bone, muscle and joint. OBJECTIVE: To investigate the index finger dexterity after cold water stimulation using computing model. METHODS: Based on the available data of the experiment about the index finger movement, the kinematic parameters of index finger in the movement were achieved. Subsequently, a clench fist kinematic model of hand was established with Anybody platform, and then a musculoskeletal model consisting of the extrinsic flexor muscles (flexor digitorum profundus and flexor digitorum superficialis) was developed to describe the changes of muscle force and contraction power in clench fist movement before and after cold simulation through inverse dynamics analysis. RESULTS AND CONCLUSION: After the cold water stimulation, the average angular velocities of the three joints of index finger were decreased during the flexing movement compared to those before cold water stimulation, and the muscle force of flexor digitorum superficialis was increased significantly in the flexing process. The contract power of flexor digitorum profundus decreased obviously, whereas the contract power of flexor digitorum superficialis was decreased slightly. The results indicate that the finger movement takes more time and the muscle force of flexor digitorum superficialis is more sensitive to the cold stimulation, which further indicates the importance of flexor digitorum superficialis in clench fist movement.