Application of a biomechanical model and combinatorial optimization to determine lower limb joints torsional stiffness in human landing

2019 ◽  
Vol 234 (2) ◽  
pp. 241-255
Author(s):  
Mehran Hatamzadeh ◽  
Reza Hassannejad ◽  
Ali Sharifnezhad
Keyword(s):  
Simulated Annealing ◽  
Combinatorial Optimization ◽  
Lower Limb ◽  
Simulated Annealing Algorithm ◽  
Sagittal Plane ◽  
Reaction Force ◽  
Biomechanical Model ◽  
Torsional Stiffness ◽  
Computation Method ◽  
Good Ability

Lower limb joint’s torsional stiffness is directly related to the individual’s performance and probability of injury when landing. There are various methods of calculating ankle, knee, and hip joint’s torsional stiffness in which the reliability of the achieved values by them are highly controversial. The purpose of this research is to provide a new method of calculating lower limb joint’s active torsional stiffness based on the body’s four-degrees-of-freedom biomechanical model. For this purpose, a group of subjects performs single-leg landing protocol from the box. In this method, the biomechanical model’s equations of motion are derived in the sagittal plane and are combined with a combinatorial optimization algorithm, which consists of genetic and simulated annealing. By the use of acquired data from the force plate and motion analysis system, combinatorial genetic algorithm–simulated annealing algorithm tries to minimize the differences between the model’s ground reaction force (GRFModel) and the GRFExperimental for each subject and thereby the joint’s torsional stiffness values are obtained. Results show that calculating lower limb joint’s torsional stiffness using the proposed method has good ability in simulating the GRFExperimental in the model. Also, the obtained values by the proposed method have moderate to good reliability and desirable variability in the measurements. Comparing the obtained stiffness values with the values of three conventional computation method in the literature shows that those common methods’ results have high computational errors, low reliability, and high variability in the measurement. Also, their ability to produce GRFModel similar to the GRFExperimental is weaker than the proposed method in single-leg landing protocol.

The Mechanical Role of the Trunk and Lower Extremities in a Seated Weight-Moving Task in the Sagittal Plane

1988 ◽  
Vol 110 (2) ◽  
pp. 97-103 ◽  
Author(s):  
K. Son ◽  
J. A. A. Miller ◽  
A. B. Schultz
Keyword(s):  
Sagittal Plane ◽  
Reaction Force ◽  
Biomechanical Model ◽  
Lower Extremities ◽  
Joint Moments ◽  
Trunk Inclination ◽  
Seated Posture ◽  
Joint Loads ◽  
Force Data

A two-dimensional, sagittally-symmetric biomechanical model was developed to analyze the joint moments required to stabilize the trunk in a seated, dynamic, weight-moving task. Kinematic and reaction force data were measured while subjects moved a hand-held weight (0–4 kgf) at shoulder level to and fro at 1 Hz. These data were then used for model input and validation purposes. A second, simpler model was used to simulate how joint loads varied with weight held, trunk inclination, and movement frequency. The results for this seated task demonstrate a) significant trunk, hip, knee, and ankle joint moments (37, 13, 4, 13 percent of maximum strength values, respectively) were required, b) considerable intersubject differences in mean joint moments (more than 66 percent) were found, which primarily were due to subtle differences in body segment kinematics and lower extremities use, and c) the important role of the lower extremities in stabilizing the trunk in the seated posture.

The Influence of Orthotics on Lower Limbs Biomechanics in CP

2019 ◽  
Vol 21 (5) ◽  
pp. 389-398
Author(s):  
Krzysztof Krasowicz
Keyword(s):  
Lower Limb ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Reaction Force ◽  
Interdisciplinary Approach ◽  
Lower Limbs ◽  
Therapeutic Success ◽  
External Moment ◽  
External Conditions

The biomechanics of the human body has a direct impact on the quality of gait cycle. Patients with Cerebral Palsy (CP) often present incorrect gait patterns associated with structural deformities which directly influence the locomotor functions. The key to therapeutic success in those patients is the use of lower limb orthotics of the AFO type. This type of orthopedic devices should correct the skeletal deformities, optimize function and ensure high quality of daily use. Alignment of the lower limb supported by orthotics in all planes is crucial for changing the abnormal position of the ground reaction force (GRF) vector during a pathological gait cycle. GRFs produce an external moment of forces that causes extension or flexion of the lower limb in the sagittal plane. At the same time, those external conditions are balanced by an internal moment of forces generated by muscles. Some of the muscles are not directly attached to the joints but still support their function. This mechanism is called biomechanical coupling. This interesting relationship is also related to the inclination or reclination of the shank vertical angle (SVA) against the foot fixed on the ground in the midstance (MST) phase of gait. An optimal SVA angle is 7–12 degrees of tibial inclination. An insufficient or excessive SVA angle can be controlled by ankle foot orthotics (AFO). Those types of splints provide for better control of foot clearance during the swing phase and support distal stability of the lower limb chain during the stance phase of the gait cycle. An interdisciplinary approach is the key to success in the therapy of CP children who use lower limb orthotics. Nowadays, tridimensional gait analysis is an important tool for objective monitoring of those patients. It shows all kinematic and kinetic data recorded during gait with AFO and therefore helps to fine-tune orthotics used by CP patients.

scholarly journals Modificación de patrones cinemáticos y electromiográficos en extremidad inferior por el uso de celular (Modification of kinematic and electromyographic patterns in the lower limb by the use of cell phones)

Retos ◽  
2020 ◽  
pp. 354-358
Author(s):  
Oscar David Valencia Cayupán ◽  
María José Hudson ◽  
Felipe Carpes ◽  
Marcos Kunzler ◽  
Fernanda Gándara ◽  
...  
Keyword(s):  
Lower Limb ◽  
Cell Phone ◽  
Sagittal Plane ◽  
Biomechanical Model ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Lower Limbs ◽  
Emg Activity ◽  
Protective Strategy ◽  
Hip Flexion

Las lesiones de transeúntes relacionadas al uso de teléfono celular han aumentado en relación con el total de accidentes peatonales. El objetivo de este estudio fue comparar variables cinemáticas y electromiográficas de ambas extremidades inferiores al enfrentar un obstáculo, con (CC) y sin (SC) el uso de celular. Diez mujeres jóvenes fueron evaluadas, las cuales caminaron y enfrentaron un obstáculo CC y SC. Con un modelo biomecánico 3D se evaluó la cinemática de extremidad inferior (plano sagital de cadera, rodilla, tobillo, junto al “toe clearance”). Al mismo tiempo se registró la actividad electromiográfica (EMG) de los siguientes músculos: tibial anterior (TA), gastrocnemio medial (GM), recto anterior (RA) y bíceps femoral (BF). Se calculó la amplitud EMG promedio de cada músculo, y el porcentaje de coactivación muscular entre: TA-GM y RA-BF. Se analizó la estrategia de ambas piernas, considerando un primer (P1) y segundo paso (P2) al cruzar el obstáculo, comparando entre una marcha CC vs CS. Según los resultados, la marcha CC incrementa el toe clearance, flexión de cadera, y la amplitud del GM, observado tanto en P1 como P2 al cruzar el obstáculo. Adicionalmente, el P2 reveló un incremento en la flexión de rodilla y tobillo. Por otro lado, la amplitud del TA y coactivación muscular entre TA-GM también aumentó CC en el P2. En conclusión, las variables cinemáticas y electromiográficas en las extremidades inferiores se modifican al cruzar un obstáculo CC. Estos hallazgos podrían indicar una estrategia protectora durante la tarea dual evaluada, minimizar el riesgo de caída. Abstract. Pedestrian injuries related to the use of cell phone have increased in relation to the total number of pedestrian accidents. The aim of this study was to compare kinematic and electromyographic variables in both lower limbs at facing an obstacle, with (WC) and without (WoC) the use of a cell phone. Ten young women were evaluated, while walking and facing an obstacle WC and WoC. A 3D biomechanical model was used to evaluate the lower limb kinematics (hip, knee, ankle in the sagittal plane, together with “toe clearance”). At the same time, the electromyographic (EMG) activity was registered in the following muscles: tibialis anterior (TA), gastrocnemius medialis (GM), rectus femoris (RF) and biceps femoris (BF). The mean EMG amplitude of each muscle and the muscular coactivation percentage between: TA-GM and RA-BF were calculated. The strategy for both lower limbs considering the first (P1) and the second step (P2) were analyzed when crossing the obstacle, comparing between gait WC vs WoC. According to results, the gait WC increase the toe clearance, hip flexion, and the GM amplitude, observed both in P1 as P2 when the person crossed the obstacle. Furthermore, the P2 revealed an increase in the knee and ankle flexion. On the other hand, the TA amplitude and the muscular coactivation between TA-GM also increased WC in the P2. In conclusion, the kinematic and electromyographic variables in the lower limbs are modified when crossing an obstacle WC. These findings could indicate a protective strategy during the dual-task evaluated, minimizing the risk of falling.

Biomechanical Performance of Habitually Barefoot and Shod Runners during Barefoot Jogging and Running

2018 ◽  
Vol 38 ◽  
pp. 1-10 ◽  
Author(s):  
Suo Di Xu ◽  
Zhi Qiang Liang ◽  
Yu Wei Liu ◽  
Gusztáv Fekete
Keyword(s):  
Lower Limb ◽  
Sagittal Plane ◽  
Center Of Pressure ◽  
Reaction Force ◽  
Three Dimensional ◽  
Frontal Plane ◽  
Influential Factor ◽  
Hip Abduction ◽  
Foot Strike ◽  
Limb Kinematics

The purpose of this study was to evaluate the biomechanical performances, running stability of habitually barefoot (BR) and shod runners (SR) during barefoot jogging and running. Ten healthy male subjects, 5 habitually shod runners and 5 habitually barefoot runners, from two different ethnics participated in this study. Subjects performed jogging (2m/s) and running (4m/s) along a 10-m runway. Three-dimensional lower-limb kinematics, ground reaction force, center of pressure (COP) and contact time (CT), were collected during testing. During jogging and running, all participants adopted rear-foot strike pattern, SR had larger VALR. SR showed significantly larger lower-limb range of motion (ROM) in sagittal plane, significantly larger hip abduction and opposite knee ROM in frontal plane, as well as significantly larger ankle internal rotation in horizontal plane. All participants’ CT showed decreased trend with running speed up; and SR was significantly longer than BR; BR and SR in COP showed different trajectories, especially forefoot and rearfoot areas. Habitually barefoot and shod runner from different ethnics still exist significant differences in lower-extremity ROM; and different foot morphological of participants is an important influential factor for these variations.

Biomechanical Factors Affecting the Peak Hand Reaction Force During the Bimanual Arrest of a Moving Mass

2001 ◽  
Vol 124 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Kurt M. DeGoede ◽  
James A. Ashton-Miller ◽  
Albert B. Schultz ◽  
Neil B. Alexander
Keyword(s):  
Sagittal Plane ◽  
Impact Force ◽  
Reaction Force ◽  
Biomechanical Model ◽  
Factors Affecting ◽  
Impact Forces ◽  
Ballistic Pendulum ◽  
Stiffness And Damping ◽  
Biomechanical Factors ◽  
The Impact

Fall-related wrist fractures are among the most common fractures at any age. In order to learn more about the biomechanical factors influencing the impact response of the upper extremities, we studied peak hand reaction force during the bimanual arrest of a 3.4 kg ballistic pendulum moving toward the subject in the sagittal plane at shoulder height. Twenty healthy young and 20 older adults, with equal gender representation, arrested the pendulum after impact at one of three initial speeds: 1.8, 2.3, or 3.0 m/sec. Subjects were asked to employ one of three initial elbow angles: 130, 150, or 170 deg. An analysis of variance showed that hand impact force decreased significantly as impact velocity decreased (50 percent/m/s) and as elbow angle decreased (0.9 percent/degree). A two segment sagittally-symmetric biomechanical model demonstrated that two additional factors affected impact forces: hand-impactor surface stiffness and damping properties, and arm segment mass. We conclude that hand impact force can be reduced by more than 40 percent by decreasing the amount of initial elbow extension and by decreasing the velocity of the hands and arms relative to the impacting surface.

KINETIC ANALYSIS OF GAIT IN THE SECOND AND THIRD TRIMESTERS OF PREGNANCY

2016 ◽  
Vol 16 (04) ◽  
pp. 1650055 ◽  
Author(s):  
MARCO BRANCO ◽  
RITA SANTOS-ROCHA ◽  
LILIANA AGUIAR ◽  
FILOMENA VIEIRA ◽  
ANTÓNIO VELOSO
Keyword(s):  
Kinetic Analysis ◽  
Lower Limb ◽  
Muscle Power ◽  
Sagittal Plane ◽  
Reaction Force ◽  
Frontal Plane ◽  
Transverse Plane ◽  
The Body ◽  
Third Trimester ◽  
The Third

Most of the anatomical changes related to the body of pregnant women occur between the second and third trimesters of pregnancy. The purposes of the study were to quantify the lower limb kinetics of gait and draw a comparison between women in the second and third trimesters of pregnancy, and a nonpregnant group. Subjects and methods: A three-dimensional (3D) kinetic analysis of gait was performed in 24 pregnant and 12 nonpregnant women. Results: Between trimesters of pregnancy, a decrease in the third peak of vertical ground reaction force (GRF) in the third trimester was observed. Most of the changes found between pregnant and nonpregnant women were in the sagittal plane for hip, knee and ankle moments, which report a decrease in mechanical load of the lower limb. In frontal plane a significant decrease in ankle joint moment was found, and in the transverse plane a significant increase in hip moment was found. Joints power decreases for hip and ankle power in sagittal and frontal plane, and increases for hip power in transverse plane. The function of propulsion and mobilization appears to be related to the different changes that occur between the right leg and left. Conclusion: These results suggest that adaptations regarding muscle participation occur first (second trimester), followed by adaptations in muscle power (third trimester). Understanding the biomechanical adaptations during pregnancy may provide more information about mechanical loads, which subsequently will be helpful for prescribing exercise and rehabilitation programs, as well as for the prevention of musculoskeletal injuries.

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