SMOOTHNESS USING ANGULAR JERK COST OF THE KNEE JOINT MOVEMENT AFTER A REDUCTION IN WALKING SPEED

2013 ◽  
Vol 13 (03) ◽  
pp. 1350037 ◽  
Author(s):  
TAKASHI FUKAYA ◽  
HIROTAKA MUTSUZAKI ◽  
YASUYOSHI WADANO
Keyword(s):  
Knee Joint ◽  
Ground Reaction Force ◽  
Stance Phase ◽  
Walking Speed ◽  
Reaction Force ◽  
Angular Acceleration ◽  
Time Dependent ◽  
Initial Contact ◽  
Joint Movement ◽  
Important Index

The angular jerk cost (AJC) was proposed to objectively represent the smoothness of joint movement by calculating the time-dependent changes in acceleration during motion. There are currently no reports focusing on smoothness using AJC measurements of the knee joint movement during the stance phase of gait. The purpose of this study was to verify whether a reduced walking speed affects the smoothness of the knee joint movement during the stance phase of gait. The gaits of 12 healthy adults were assessed. A slower walker showed a significant reduction in the AJC value in the period between the initial contact and the loading response, as compared with someone walking at a comfortable speed. The maximum ground reaction force of the stance phase at a comfortable walking speed was significantly larger than that at a slower walking speed. Thus, although the smoothness of the knee joint was impaired by a rapid load in the early stance phase, a slower walking speed reduced the ground reaction force and angular acceleration of the knee joint and created a smoother movement. The AJC can be an important index for understanding the smoothness of the knee joint in the early stance phase.

RELATIONSHIPS BETWEEN KINETIC VARIABLES AND SMOOTHNESS OF KNEE JOINT MOVEMENT IN THE STANCE PHASE

2014 ◽  
Vol 14 (05) ◽  
pp. 1450079 ◽  
Author(s):  
TAKASHI FUKAYA ◽  
HIROTAKA MUTSUZAKI ◽  
HAJIME ITO ◽  
YASUYOSHI WADANO
Keyword(s):  
Knee Joint ◽  
Ground Reaction Force ◽  
Stance Phase ◽  
Reaction Force ◽  
Vertical Component ◽  
Correlation Coefficients ◽  
The Other ◽  
Joint Movement ◽  
Important Index ◽  
Three Phases

The purposes of this study were to clarify which period of the stance phase shows the greatest decrease in the smoothness of the knee joint movement and to analyze the relationships between kinetic variables and the smoothness of the knee joint movement during the stance phase using the angular jerk cost (AJC). The study subjects were 11 healthy adults. To clarify the relationships between the kinetic variables and the AJC, Pearson's product correlation coefficients were calculated for the AJC and three kinetic variables. The AJC in the early stance phase was significantly larger than those in the other three phases, and it was confirmed that the early stance phase showed the greatest decrease in smoothness of the knee joint movement. Furthermore, there was a positive correlation between the AJC and the vertical component of the ground reaction force in the early stance phase. Correlations between the AJC and the kinetic variables were also found in the other three phases. Regarding evaluation of the smoothness of the knee joint movement using the AJC based on the present results, the AJC may be an important index for understanding the dynamics of the knee joint in the early stance phase.

Compliant orthoses for repositioning of knee joint based on super-elasticity of shape memory alloys

2018 ◽  
Vol 29 (15) ◽  
pp. 3136-3150 ◽  
Author(s):  
Farshid Sadeghian ◽  
Mohammad Reza Zakerzadeh ◽  
Morad Karimpour ◽  
Mostafa Baghani
Keyword(s):  
Knee Joint ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Muscle Weakness ◽  
Stance Phase ◽  
Quadriceps Muscle ◽  
Patient Specific ◽  
Initial Contact ◽  
Joint Movement ◽  
Distinct Level

People suffering from neuromuscular diseases may also face certain abnormalities in their walking pattern. Patients with quadriceps muscle weakness suffer from flexion contracture as well as flexion instability during the gait cycle. In this article, a knee-ankle-foot orthosis design is proposed with two different mechanisms for the stance and swing phases, addressing the needs of patients with quadriceps muscle weakness. The stance phase mechanism locks the knee joint movement from the initial contact until the end of mid-swing and after mid-stance phase, the knee joint can flex freely. OpenSim was utilized to simulate patients with muscle weakness as well as calculating the required moment to mimic the stiffness of a normal knee joint. The super-elasticity of shape memory alloys was then used to reproduce the calculated moment for different levels of muscle weakness. It is shown that by designing patient-specific orthosis, the stiffness profile of normal joint for each patient with distinct level of muscle weakness can be reproduced.

Modeling the resistance mechanism of passive knee joint flexion and extension for use in rehabilitation equipment

2021 ◽  
pp. 095441192199013
Author(s):  
Mansoor Amiri ◽  
Farhad Tabatabai Ghomsheh ◽  
Farshad Ghazalian
Keyword(s):  
Knee Joint ◽  
Sagittal Plane ◽  
Resistance Mechanism ◽  
Time Dependent ◽  
Coefficient Of Determination ◽  
Joint Movement ◽  
Elastic Coefficient ◽  
Knee Movement ◽  
Joint Flexion ◽  
Flexion And Extension

The purpose of this study was to model the resistance mechanism of Passive Knee Joint Flexion and Extension to create a similar torque mechanism in rehabilitation equipment. In order to better model the behavior of passive knee tissues, it is necessary to exactly calculate the two coefficients of elasticity of time-independent and time-dependent parts. Ten healthy male volunteers (mean height 176.4+/−4.59 cm) participated in this study. Passive knee joint flexion and extension occurred at velocities of 15, 45, and 120 (degree/s), and in five consecutive cycles and within the range of 0 to 100° of knee movement on the sagittal plane on Cybex isokinetic dynamometer. To ensure that the muscles were relaxed, the electrical activity of knee muscles was recorded. The elastic coefficient, (KS) increased with elevating the passive velocity in flexion and extension. The elastic coefficient, (KP) was observed to grow with the passive velocity increase. While, the viscous coefficient (C) diminished with passive velocity rise in extension and flexion. The heightened passive velocity of the motion resulted in increased hysteresis (at a rate of 42%). The desired of passive velocity is lower so that there is less energy lost and the viscoelastic resistance of the tissue in the movement decreases. The Coefficient of Determination, R2 between the model-responses and experimental curves in the extension was 0.96 < R2 < 0.99 and in flexion was 0.95 < R2 < 0.99. This modeling is capable of predicting the true performance of the components of passive knee movement and we can create a resistance mechanism in the rehabilitation equipment to perform knee joint movement. Quantitative measurements of two elastic coefficients of Time-independent and Time-dependent parts passive knee joint coefficients should be used for better accurate simulation the behavior of passive tissues in the knee which is not seen in other studies.

scholarly journals Balancing on a narrow ridge: biomechanics and control

1999 ◽  
Vol 354 (1385) ◽  
pp. 869-875 ◽  
Author(s):  
E. Otten
Keyword(s):  
Hip Joint ◽  
Ground Reaction Force ◽  
Inverted Pendulum ◽  
Reaction Force ◽  
Angular Acceleration ◽  
Centre Of Mass ◽  
Inverted Pendulum Model ◽  
Pendulum Model ◽  
Narrow Ridge ◽  
Standing Humans

The balance of standing humans is usually explained by the inverted pendulum model. The subject invokes a horizontal ground–reaction force in this model and controls it by changing the location of the centre of pressure under the foot or feet. In experiments I showed that humans are able to stand on a ridge of only a few millimetres wide on one foot for a few minutes. In the present paper I investigate whether the inverted pendulum model is able to explain this achievement. I found that the centre of mass of the subjects sways beyond the surface of support, rendering the inverted pendulum model inadequate. Using inverse simulations of the dynamics of the human body, I found that hip–joint moments of the stance leg are used to vary the horizontal component of the ground–reaction force. This force brings the centre of mass back over the surface of support. The subjects generate moments of force at the hip–joint of the swing leg, at the shoulder–joints and at the neck. These moments work in conjunction with a hip strategy of the stance leg to limit the angular acceleration of the head–arm–trunk complex. The synchrony of the variation in moments suggests that subjects use a motor programme rather than long latency reflexes.

A Comparison of Computation Methods for Leg Stiffness During Hopping

2014 ◽  
Vol 30 (1) ◽  
pp. 154-159 ◽  
Author(s):  
Hiroaki Hobara ◽  
Koh Inoue ◽  
Yoshiyuki Kobayashi ◽  
Toru Ogata
Keyword(s):  
Ground Reaction Force ◽  
Stance Phase ◽  
Center Of Mass ◽  
Reaction Force ◽  
Sine Wave ◽  
Phase Method ◽  
Leg Stiffness ◽  
Mass Displacement ◽  
Male Subjects ◽  
Oscillation Method

Despite the presence of several different calculations of leg stiffness during hopping, little is known about how the methodologies produce differences in the leg stiffness. The purpose of this study was to directly compareKlegduring hopping as calculated from three previously published computation methods. Ten male subjects hopped in place on two legs, at four frequencies (2.2, 2.6, 3.0, and 3.4 Hz). In this article, leg stiffness was calculated from the natural frequency of oscillation (method A), the ratio of maximal ground reaction force (GRF) to peak center of mass displacement at the middle of the stance phase (method B), and an approximation based on sine-wave GRF modeling (method C). We found that leg stiffness in all methods increased with an increase in hopping frequency, butKlegvalues using methods A and B were significantly higher than when using method C at all hopping frequencies. Therefore, care should be taken when comparing leg stiffness obtained by method C with those calculated by other methods.

scholarly journals Effects of Restricted Knee Flexion and Walking Speed on the Vertical Ground Reaction Force During Gait

1997 ◽  
Vol 25 (4) ◽  
pp. 236-244 ◽  
Author(s):  
Thomas M. Cook ◽  
Kevin P. Farrell ◽  
Iva A. Carey ◽  
Joan M. Gibbs ◽  
Gregory E. Wiger
Keyword(s):  
Ground Reaction Force ◽  
Knee Flexion ◽  
Walking Speed ◽  
Reaction Force ◽  
Vertical Ground Reaction Force ◽  
Vertical Ground
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