The hindlimbs play a crucial role in bird locomotion,making the biomechanical properties of the musculoskeletal system in these limbs a focal point for researchers studying avian behaviour.However,a comprehensive anal...The hindlimbs play a crucial role in bird locomotion,making the biomechanical properties of the musculoskeletal system in these limbs a focal point for researchers studying avian behaviour.However,a comprehensive analysis of the mechanical performance within the long bones of hindlimbs during locomotion remains lacking.In the present study,the strain and deformation of the femur of Cabot’s Tragopans(Tragopan caboti)were estimated.We employed inverse simulation to calculate the force and moment of femoral muscles during mid-stance terrestrial locomotion and conducted finite element analysis to calculate femoral strain.Results showed that during mid-stance,the femur experiences combined deformation primarily characterized by torsion,bending,and compression.It emphasises the importance of considering the influence of varying loads on bone adaptation when investigating bone form-function relationships.Muscles were found to play a significant role in offsetting joint loads on the femur,subsequently reducing the deformation and overall strain on the bone.This reduction enhances femoral safety during locomotion,allowing birds to meet mechanical demands while maintaining a lightweight bone structure.Notably,the M.iliotrochantericus caudalis significantly reduces torsional deformation of the proximal femur,protecting the vulnerable femoral neck from high fracture risk induced by rotation load.Given that the femur torsion during terrestrial locomotion in birds is associated with changes in hindlimb posture due to their adaptation to flight,the characteristics of M.iliotrochantericus caudalis may provide insight into the locomotor evolution of theropods and the origin of avian flight.展开更多
Objective To study the improvement of infarcted myocardial contractile force after autologous skeletal muscle satellite cell implantation via intracoronary arterial perfusion. Methods Skeletal muscle cells were harves...Objective To study the improvement of infarcted myocardial contractile force after autologous skeletal muscle satellite cell implantation via intracoronary arterial perfusion. Methods Skeletal muscle cells were harvested from gluteus max of adult mongrel dogs and the cells were cultured and expanded before being labeled with DAPI (4’, 6-diamidino-2-phenylindone). The labeled cells were then implanted into the acute myocardial infarct site via the ligated left anterior descending (LAD) coronary artery. Specimens were taken at 2nd, 4th, 8th week after myoblast implantation for histologic and contractile force evaluation, respectively. Results The satellite cells with fluorescence had been observed in the infarct site and also in papi- llary muscle with consistent oriented direction of host myocardium. A portion of the implanted cells had differen- tiated into muscle fibers. Two weeks after implantation, the myocardial contractile force showed no significant difference between the cell implant group and control group. At 4 and 8 week, the contractile force in the cell implant group was better than that in control group. Conclusion The skeletal muscle satellite cells, implanted into infarct myocardium by intracoronary arterial perfusion, could disseminate through the entire infarcted zone with myocardial regeneration and improve the contractile function of the infarcted myocardium.展开更多
Added mass provided irregular interference towards human movement and shifted the force generated by lower limb muscles.However,the association between mass and muscle activities is not well recognized.Our study aims ...Added mass provided irregular interference towards human movement and shifted the force generated by lower limb muscles.However,the association between mass and muscle activities is not well recognized.Our study aims at investigating the influence of added mass on lower limbs.In our study,five young,healthy walkers performed walking trials under three load conditions(unload;C1:0.25 pounds on feet,1 pound on calves,and 2 pounds on thighs;C2:1 pound on feet,2 pounds on calves,and 4 pounds on thighs).During walking,three-dimensional kinematics,sEMG signals,and oxygen consumption were collected which allowed us to understand the effects of added mass on muscles.We also generated OpenSim simulation,designed to comprehend the relationship between added mass and muscles.With the increase of added mass,maximum sEMG signal and peak joint torque increased;whereas,the horizontal stride time reduced(unload:1.697±0.02 s,C1:1.651±0.02 s,C2:1.622±0.02 s).Energy expenditure raised correspondingly(C1:6.53%,C2:24.85%).Moreover,joint moment increased,while same change occurred in muscle force.Overall,our results show that participants responded positively to additional mass by adjusting muscle activities,joint movement,and stride frequency,which demonstrates the relationship between energy consumption and added mass.展开更多
Adolescent idiopathic scoliosis seriously affects the physical and mental health of adolescents.In thepast,the research on therapeutic orthosis ignored the influence of muscle factors.Aimed at this problem,basedon the...Adolescent idiopathic scoliosis seriously affects the physical and mental health of adolescents.In thepast,the research on therapeutic orthosis ignored the influence of muscle factors.Aimed at this problem,basedon the principle of reverse engineering,through the spine computed tomography data model of three-dimensionalreconstruction,muscle forces around the spine are imported into the spinal muscle force model and AnyBodysoftware is used for simulation.The geometric similarity and biomechanical effectiveness of the established modelare verified.In order to obtain the relationship among the applied orthopedic force,Cobb angle and vertebraldisplacement,a finite element model conforming to spinal anatomy is established,and then the biomechanicalanalysis of the finite element model of the scoliosis is carried out.Reasonable control of paravertebral muscles canplay a positive role in orthopedic treatment,and the fitting equation can provide a reference for doctors to applythe orthopedic force on patient.展开更多
Background:Muscular strength can be conceptually determined by two components:muscle activation and size.Muscle activation by the central nervous system can be measured by surface electromyography(sEMG).Muscular size ...Background:Muscular strength can be conceptually determined by two components:muscle activation and size.Muscle activation by the central nervous system can be measured by surface electromyography(sEMG).Muscular size reflects the amount of contractile protein within a skeletal muscle and can be estimated by anthropometric measurements.The purpose of this study was to determine the relative contributions of size parameters and muscle activation to the prediction of maximal voluntary isometric elbow flexion strength. Methods:A series of anthropometric measurements were taken from 96 participants.Torque and root-mean-square(RMS) of the sEMG from the biceps brachii were averaged across three maximal voluntary isometric contractions.A multiple linear regression analysis was performed based on a Pearson's correlation matrix. Results:Body weight(BW) accounted for 39.1% and 27.3% in males and females,respectively,and was the strongest predictor of strength for males.Forearm length(L3) was the strongest predictor of strength in females(partial R^2 = 0.391).Elbow circumference(ELB) accounted for a significant(p < 0.05) amount of variance in males but not females.The addition of sEMG RMS as a third variable accounted for an average of 10.1% of the variance excluding the equation of BW and L3 in females.The strongest prediction equation included BW,L3,and ELB accounting for 55.6% and 58.5% of the variance in males and females,respectively. Conclusion:Anthropometrics provide a strong prediction equation for the estimation of isometric elbow flexion strength.Muscle activation,as measured by sEMG activity,accounted for a significant(p < 0.05) amount of variance in most prediction equations,however,its contribution was comparable to an additional anthropometric variable.展开更多
A new method to reconstruct a comparatively complete muscle model of the human lower limb from CT and MRI data is presented. Topological structure of more than fourteen muscles is built and coordinates of origin and i...A new method to reconstruct a comparatively complete muscle model of the human lower limb from CT and MRI data is presented. Topological structure of more than fourteen muscles is built and coordinates of origin and insertion points are given. Based on this model, straight-line model and centroid-line muscle model are acquired. Muscle force prediction is discussed according to the model reconstructed, and a multi-objective optimization method is put forward for evaluating muscle forces of the human lower extremity.展开更多
A biomechanical musculo-skeletal model of upper limb is presented in this paper,which can provide accurate representations of muscles and joints,and capture important interactions between joints.The upper limb model i...A biomechanical musculo-skeletal model of upper limb is presented in this paper,which can provide accurate representations of muscles and joints,and capture important interactions between joints.The upper limb model is made up of seven segments:ribs,sternum,clavicle,scapular,humerus,radius and ulna,considered as a single rigid body respectively and includes 22 muscles.The individual muscle forces can be calculated by using an electromyography (EMG) assisted method,which is verified by comparing the simulation results with other researches of an elbow flexion motion.These comparisons show that the muscle forces and the estimated joint moment match well with previous literatures.展开更多
Background: Acute effects of Far Infrared (FIR) treatment in horses are unknown, especially short periods of 30 minutes, as is any effect on such muscle parameters as warm-up balance, overall exercise balance and late...Background: Acute effects of Far Infrared (FIR) treatment in horses are unknown, especially short periods of 30 minutes, as is any effect on such muscle parameters as warm-up balance, overall exercise balance and laterality asymmetries. Aim: This study examines three equine cases in detail to measure any effects of a short period of FIR treatment. Methods: Multi-frequency bioimpedance (mfBIA) and acoustic myography (AMG), non-invasive techniques, were applied pre- and post-treatment with FIR to the back (T5-L4/5) and for m.Longissimus dorsi and m.Gluteus medius was recorded during a 15-minute warm-up regimen. mfBIA parameters included extracellular resistance (Re), centre frequency (fc), membrane capacitance (Mc), intracellular resistance (Ri) and phase angle (PA) which indicates level of training and health status. Results: FIR treatment responses for mfBIA parameters were found to be horse-specific and different, whilst in terms of AMG, FIR treatment for 30 minutes had a beneficial effect on overall balance in all three horses (5 out of 6 muscles), and a beneficial effect on the AMG parameter ST (force symmetry) in all three horses (6 out of 6 muscles). An overall improvement for combined balance and ST values for both muscles and all three horses of 86% was noted with FIR treatment, compared to 56% without. Conclusions: This preliminary study of FIR treatment in three horses, has been found to result in an overall improvement in combined balance and ST values for both muscles. FIR has potential as a promising treatment to reduce the risk of warm-up-related injuries in athletic horses.展开更多
In a crash situation,drivers typically make evasive maneuvers before an upcoming impact,which can affect the kinematics and injury during impact.The purpose of the current study was to investigate the response and eff...In a crash situation,drivers typically make evasive maneuvers before an upcoming impact,which can affect the kinematics and injury during impact.The purpose of the current study was to investigate the response and effect of drivers’cervical muscles in a frontal impact.A crash scenario was developed using a vehicle driving simulator,and 10 volunteers were employed to drive the simulator at 20 km/h,50 km/h,80 km/h and 100 km/h.Electromyography(EMG)was recorded from the sternocleidomastoideus(SCM),splenius cervicis(SPL)and trapezium(TRP)muscles using a data acquisition system,and the level of muscle activation was calculated.A numerical study was conducted using data collected in the experiment.The results revealed that the cervical muscles were activated during drivers’protective action.EMG activity of cervical muscles before impact was greater than that during normal driving.EMG activity increased with driving speed,with the SCM and TRP exhibiting larger increases than the SPL.The kinematics and load of the driver were influenced by muscle activation.Before the collision,the head of an active model stretched backward,while the passive model kept the head upright.In low-speed impact,the torque and shear of the cervical muscle in the active model were much lower than those in the passive model,while the tension of the cervical muscle was higher in the active model compared with the passive model.The results indicated that the incidence of cervical injury in high-speed impact is complex.展开更多
A non-equilibrium statistical method is used to study the collective characteristics of myosin II motors in a sarcomere during its contraction. By means of Fokker-Planck equation of molecular motors, we present a dyna...A non-equilibrium statistical method is used to study the collective characteristics of myosin II motors in a sarcomere during its contraction. By means of Fokker-Planck equation of molecular motors, we present a dynamic mechanical model for the sarcomere in skeletal muscle. This model has been solved with a numerical algorithm based on experimental chemical transition rates. The influences of ATP concentration and load on probability density, contraction velocity and maximum active force are discussed respectively. It is shown that contraction velocity and maximum isometric active force increase with the increasing ATP concentration and become constant when the ATP concentration reaches equilibrium saturation. Contraction velocity reduces gradually as the load force increases. We also find that active force begins to increase then decrease with the increasing length of sarcomere, and has a maximum value at the optimal length that all myosin motors can attach to actin filament. Our results are in good agreement with the Hill muscle model.展开更多
基金supported by the National Natural Science Foundation of China(No.31471951,No.31970411).
文摘The hindlimbs play a crucial role in bird locomotion,making the biomechanical properties of the musculoskeletal system in these limbs a focal point for researchers studying avian behaviour.However,a comprehensive analysis of the mechanical performance within the long bones of hindlimbs during locomotion remains lacking.In the present study,the strain and deformation of the femur of Cabot’s Tragopans(Tragopan caboti)were estimated.We employed inverse simulation to calculate the force and moment of femoral muscles during mid-stance terrestrial locomotion and conducted finite element analysis to calculate femoral strain.Results showed that during mid-stance,the femur experiences combined deformation primarily characterized by torsion,bending,and compression.It emphasises the importance of considering the influence of varying loads on bone adaptation when investigating bone form-function relationships.Muscles were found to play a significant role in offsetting joint loads on the femur,subsequently reducing the deformation and overall strain on the bone.This reduction enhances femoral safety during locomotion,allowing birds to meet mechanical demands while maintaining a lightweight bone structure.Notably,the M.iliotrochantericus caudalis significantly reduces torsional deformation of the proximal femur,protecting the vulnerable femoral neck from high fracture risk induced by rotation load.Given that the femur torsion during terrestrial locomotion in birds is associated with changes in hindlimb posture due to their adaptation to flight,the characteristics of M.iliotrochantericus caudalis may provide insight into the locomotor evolution of theropods and the origin of avian flight.
文摘Objective To study the improvement of infarcted myocardial contractile force after autologous skeletal muscle satellite cell implantation via intracoronary arterial perfusion. Methods Skeletal muscle cells were harvested from gluteus max of adult mongrel dogs and the cells were cultured and expanded before being labeled with DAPI (4’, 6-diamidino-2-phenylindone). The labeled cells were then implanted into the acute myocardial infarct site via the ligated left anterior descending (LAD) coronary artery. Specimens were taken at 2nd, 4th, 8th week after myoblast implantation for histologic and contractile force evaluation, respectively. Results The satellite cells with fluorescence had been observed in the infarct site and also in papi- llary muscle with consistent oriented direction of host myocardium. A portion of the implanted cells had differen- tiated into muscle fibers. Two weeks after implantation, the myocardial contractile force showed no significant difference between the cell implant group and control group. At 4 and 8 week, the contractile force in the cell implant group was better than that in control group. Conclusion The skeletal muscle satellite cells, implanted into infarct myocardium by intracoronary arterial perfusion, could disseminate through the entire infarcted zone with myocardial regeneration and improve the contractile function of the infarcted myocardium.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51205182)Key research&Development plan of Jiangsu Province(Grant No.BE2019724).
文摘Added mass provided irregular interference towards human movement and shifted the force generated by lower limb muscles.However,the association between mass and muscle activities is not well recognized.Our study aims at investigating the influence of added mass on lower limbs.In our study,five young,healthy walkers performed walking trials under three load conditions(unload;C1:0.25 pounds on feet,1 pound on calves,and 2 pounds on thighs;C2:1 pound on feet,2 pounds on calves,and 4 pounds on thighs).During walking,three-dimensional kinematics,sEMG signals,and oxygen consumption were collected which allowed us to understand the effects of added mass on muscles.We also generated OpenSim simulation,designed to comprehend the relationship between added mass and muscles.With the increase of added mass,maximum sEMG signal and peak joint torque increased;whereas,the horizontal stride time reduced(unload:1.697±0.02 s,C1:1.651±0.02 s,C2:1.622±0.02 s).Energy expenditure raised correspondingly(C1:6.53%,C2:24.85%).Moreover,joint moment increased,while same change occurred in muscle force.Overall,our results show that participants responded positively to additional mass by adjusting muscle activities,joint movement,and stride frequency,which demonstrates the relationship between energy consumption and added mass.
文摘Adolescent idiopathic scoliosis seriously affects the physical and mental health of adolescents.In thepast,the research on therapeutic orthosis ignored the influence of muscle factors.Aimed at this problem,basedon the principle of reverse engineering,through the spine computed tomography data model of three-dimensionalreconstruction,muscle forces around the spine are imported into the spinal muscle force model and AnyBodysoftware is used for simulation.The geometric similarity and biomechanical effectiveness of the established modelare verified.In order to obtain the relationship among the applied orthopedic force,Cobb angle and vertebraldisplacement,a finite element model conforming to spinal anatomy is established,and then the biomechanicalanalysis of the finite element model of the scoliosis is carried out.Reasonable control of paravertebral muscles canplay a positive role in orthopedic treatment,and the fitting equation can provide a reference for doctors to applythe orthopedic force on patient.
基金supported by the Natural Sciences and Engineering Research Council of Canada
文摘Background:Muscular strength can be conceptually determined by two components:muscle activation and size.Muscle activation by the central nervous system can be measured by surface electromyography(sEMG).Muscular size reflects the amount of contractile protein within a skeletal muscle and can be estimated by anthropometric measurements.The purpose of this study was to determine the relative contributions of size parameters and muscle activation to the prediction of maximal voluntary isometric elbow flexion strength. Methods:A series of anthropometric measurements were taken from 96 participants.Torque and root-mean-square(RMS) of the sEMG from the biceps brachii were averaged across three maximal voluntary isometric contractions.A multiple linear regression analysis was performed based on a Pearson's correlation matrix. Results:Body weight(BW) accounted for 39.1% and 27.3% in males and females,respectively,and was the strongest predictor of strength for males.Forearm length(L3) was the strongest predictor of strength in females(partial R^2 = 0.391).Elbow circumference(ELB) accounted for a significant(p < 0.05) amount of variance in males but not females.The addition of sEMG RMS as a third variable accounted for an average of 10.1% of the variance excluding the equation of BW and L3 in females.The strongest prediction equation included BW,L3,and ELB accounting for 55.6% and 58.5% of the variance in males and females,respectively. Conclusion:Anthropometrics provide a strong prediction equation for the estimation of isometric elbow flexion strength.Muscle activation,as measured by sEMG activity,accounted for a significant(p < 0.05) amount of variance in most prediction equations,however,its contribution was comparable to an additional anthropometric variable.
文摘A new method to reconstruct a comparatively complete muscle model of the human lower limb from CT and MRI data is presented. Topological structure of more than fourteen muscles is built and coordinates of origin and insertion points are given. Based on this model, straight-line model and centroid-line muscle model are acquired. Muscle force prediction is discussed according to the model reconstructed, and a multi-objective optimization method is put forward for evaluating muscle forces of the human lower extremity.
基金the National Natural Science Foundation of China(No. 30530230)
文摘A biomechanical musculo-skeletal model of upper limb is presented in this paper,which can provide accurate representations of muscles and joints,and capture important interactions between joints.The upper limb model is made up of seven segments:ribs,sternum,clavicle,scapular,humerus,radius and ulna,considered as a single rigid body respectively and includes 22 muscles.The individual muscle forces can be calculated by using an electromyography (EMG) assisted method,which is verified by comparing the simulation results with other researches of an elbow flexion motion.These comparisons show that the muscle forces and the estimated joint moment match well with previous literatures.
文摘Background: Acute effects of Far Infrared (FIR) treatment in horses are unknown, especially short periods of 30 minutes, as is any effect on such muscle parameters as warm-up balance, overall exercise balance and laterality asymmetries. Aim: This study examines three equine cases in detail to measure any effects of a short period of FIR treatment. Methods: Multi-frequency bioimpedance (mfBIA) and acoustic myography (AMG), non-invasive techniques, were applied pre- and post-treatment with FIR to the back (T5-L4/5) and for m.Longissimus dorsi and m.Gluteus medius was recorded during a 15-minute warm-up regimen. mfBIA parameters included extracellular resistance (Re), centre frequency (fc), membrane capacitance (Mc), intracellular resistance (Ri) and phase angle (PA) which indicates level of training and health status. Results: FIR treatment responses for mfBIA parameters were found to be horse-specific and different, whilst in terms of AMG, FIR treatment for 30 minutes had a beneficial effect on overall balance in all three horses (5 out of 6 muscles), and a beneficial effect on the AMG parameter ST (force symmetry) in all three horses (6 out of 6 muscles). An overall improvement for combined balance and ST values for both muscles and all three horses of 86% was noted with FIR treatment, compared to 56% without. Conclusions: This preliminary study of FIR treatment in three horses, has been found to result in an overall improvement in combined balance and ST values for both muscles. FIR has potential as a promising treatment to reduce the risk of warm-up-related injuries in athletic horses.
基金This work is supported by National Natural Science Foundation of China(Nos.51775236,51675224,U1564214)National Key R&D Program of China(Nos.2017YFB0102600,2018YFB0105205).
文摘In a crash situation,drivers typically make evasive maneuvers before an upcoming impact,which can affect the kinematics and injury during impact.The purpose of the current study was to investigate the response and effect of drivers’cervical muscles in a frontal impact.A crash scenario was developed using a vehicle driving simulator,and 10 volunteers were employed to drive the simulator at 20 km/h,50 km/h,80 km/h and 100 km/h.Electromyography(EMG)was recorded from the sternocleidomastoideus(SCM),splenius cervicis(SPL)and trapezium(TRP)muscles using a data acquisition system,and the level of muscle activation was calculated.A numerical study was conducted using data collected in the experiment.The results revealed that the cervical muscles were activated during drivers’protective action.EMG activity of cervical muscles before impact was greater than that during normal driving.EMG activity increased with driving speed,with the SCM and TRP exhibiting larger increases than the SPL.The kinematics and load of the driver were influenced by muscle activation.Before the collision,the head of an active model stretched backward,while the passive model kept the head upright.In low-speed impact,the torque and shear of the cervical muscle in the active model were much lower than those in the passive model,while the tension of the cervical muscle was higher in the active model compared with the passive model.The results indicated that the incidence of cervical injury in high-speed impact is complex.
基金supported by the National Natural Science Foundation of China (Grant No. 61075101/60643002)the Research Fund of State Key Laboratory of MSV, China (Grant No. MSV-2010-1)+2 种基金the National High-Tech Research and Development Program of China (Grant No. 2006AA04Z240)the Shanghai Dawn Program (Grant No. 07SG14)the Medical and Technology Intercrossing Research Foundation of Shanghai Jiao Tong University (Grant No. YG2010ZD101)
文摘A non-equilibrium statistical method is used to study the collective characteristics of myosin II motors in a sarcomere during its contraction. By means of Fokker-Planck equation of molecular motors, we present a dynamic mechanical model for the sarcomere in skeletal muscle. This model has been solved with a numerical algorithm based on experimental chemical transition rates. The influences of ATP concentration and load on probability density, contraction velocity and maximum active force are discussed respectively. It is shown that contraction velocity and maximum isometric active force increase with the increasing ATP concentration and become constant when the ATP concentration reaches equilibrium saturation. Contraction velocity reduces gradually as the load force increases. We also find that active force begins to increase then decrease with the increasing length of sarcomere, and has a maximum value at the optimal length that all myosin motors can attach to actin filament. Our results are in good agreement with the Hill muscle model.
