Accuracy of Leg Kinematics in Estimating Key Gait Events for Amputees

2021 ◽  
Author(s):  
Zohaib Aftab ◽  
Nazia Gillani
Keyword(s):  
Leg Kinematics

scholarly journals Body side-specific changes in sensorimotor processing of movement feedback in a walking insect

2019 ◽  
Vol 122 (5) ◽  
pp. 2173-2186 ◽  
Author(s):  
Joscha Schmitz ◽  
Matthias Gruhn ◽  
Ansgar Büschges
Keyword(s):  
Stick Insect ◽  
The Body ◽  
Motor Output ◽  
Chordotonal Organ ◽  
Stimulus Velocity ◽  
Motor Processing ◽  
Sensorimotor Processing ◽  
Body Side ◽  
The Difference ◽  
Leg Kinematics

Feedback from load and movement sensors can modify timing and magnitude of the motor output in the stepping stick insect. One source of feedback is stretch reception by the femoral chordotonal organ (fCO), which encodes such parameters as the femorotibial (FTi) joint angle, the angular velocity, and its acceleration. Stimulation of the fCO causes a postural resistance reflex, during quiescence, and can elicit the opposite, so-called active reaction (AR), which assists ongoing flexion during active movements. In the present study, we investigated the role of fCO feedback for the difference in likelihood of generating ARs on the inside vs. the outside during curve stepping. We analyzed the effects of fCO stimulation on the motor output to the FTi and the neighboring coxa-trochanter and thorax-coxa joints of the middle leg. In inside and outside turns, the probability for ARs increases with increasing starting angle and decreasing stimulus velocity; furthermore, it is independent of the total angular excursion. However, the transition between stance and swing motor activity always occurs after a specific angular excursion, independent of the turning direction. Feedback from the fCO also has an excitatory influence on levator trochanteris motoneurons (MNs) during inside and outside turns, whereas the same feedback affects protractor coxae MNs only during outside steps. Our results suggest joint- and body side-dependent processing of fCO feedback. A shift in gain may be responsible for different AR probabilities between inside and outside turning, whereas the general control mechanism for ARs is unchanged. NEW & NOTEWORTHY We show that parameters of movement feedback from the tibia in an insect during curve walking are processed in a body side-specific manner, and how. From our results it is highly conceivable that the difference in motor response to the feedback supports the body side-specific leg kinematics during turning. Future studies will need to determine the source for the inputs that determine the local changes in sensory-motor processing.

scholarly journals The Appropriateness of the Helical Axis Technique and Six Available Cardan Sequences for the Representation of 3-D Lead Leg Kinematics During the Fencing Lunge

2013 ◽  
Vol 37 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Jonathan Sinclair ◽  
Paul J Taylor ◽  
Lindsay Bottoms
Keyword(s):  
Repeated Measures ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Helical Axis ◽  
Kinematic Parameters ◽  
Kinematic Data ◽  
Intraclass Correlations ◽  
Common Technique ◽  
Rotation Plane ◽  
Leg Kinematics

Cardan/Euler angles represent the most common technique for the quantification of segmental rotations. Cardan angles are influenced by their ordered sequence, and sensitive to planar-cross talk from the dominant rotation plane, which may affect the angular parameters. The International Society of Biomechanics (ISB) currently recommends a sagittal, coronal, and then transverse (XYZ) ordered sequence, although it has been proposed that when quantifying non-sagittal rotations this may not be the most appropriate technique. This study examined the influence of the helical and six available Cardan sequences on lower extremity three-dimensional (3-D) kinematics of the lead leg during the fencing lunge. Kinematic data were obtained using a 3-D motion capture system as participants completed simulated lunges. Repeated measures ANOVAs were used to compare discrete kinematic parameters, and intraclass correlations were also utilized to determine evidence of planar crosstalk. The results indicate that in all three planes of rotation, peak angle and range of motion angles using the YXZ and ZXY sequences were significantly greater than the other sequences. It was also noted that the utilization of the YXZ and ZXY sequences was associated with the strongest correlations from the sagittal plane, and the XYZ sequence was found habitually to be associated with the lowest correlations. It appears that for accurate representation of 3-D kinematics of the lead leg during the fencing lunge, the XYZ sequence is the most appropriate and as such its continued utilization is encouraged.

Ground reaction forces and dominant leg kinematics during a rapid stop and jump

1989 ◽  
Vol 22 (10) ◽  
pp. 1082
Author(s):  
Robert Shapiro ◽  
Joe Threlkeld ◽  
J.Michael Ray
Keyword(s):  
Ground Reaction Forces ◽  
Reaction Forces ◽  
Leg Kinematics

scholarly journals Closed-loop neuromodulation of spinal sensorimotor circuits controls refined locomotion after complete spinal cord injury

2014 ◽  
Vol 6 (255) ◽  
pp. 255ra133-255ra133 ◽  
Author(s):  
Nikolaus Wenger ◽  
Eduardo Martin Moraud ◽  
Stanisa Raspopovic ◽  
Marco Bonizzato ◽  
Jack DiGiovanna ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Real Time ◽  
Therapeutic Potential ◽  
Embedded Control ◽  
Control Loops ◽  
Cord Injury ◽  
Technological Platform ◽  
Complete Spinal Cord Injury ◽  
Leg Kinematics

Neuromodulation of spinal sensorimotor circuits improves motor control in animal models and humans with spinal cord injury. With common neuromodulation devices, electrical stimulation parameters are tuned manually and remain constant during movement. We developed a mechanistic framework to optimize neuromodulation in real time to achieve high-fidelity control of leg kinematics during locomotion in rats. We first uncovered relationships between neuromodulation parameters and recruitment of distinct sensorimotor circuits, resulting in predictive adjustments of leg kinematics. Second, we established a technological platform with embedded control policies that integrated robust movement feedback and feed-forward control loops in real time. These developments allowed us to conceive a neuroprosthetic system that controlled a broad range of foot trajectories during continuous locomotion in paralyzed rats. Animals with complete spinal cord injury performed more than 1000 successive steps without failure, and were able to climb staircases of various heights and lengths with precision and fluidity. Beyond therapeutic potential, these findings provide a conceptual and technical framework to personalize neuromodulation treatments for other neurological disorders.

scholarly journals Stable Balance Adjustment Structure of the Quadruped Robot Based on the Bionic Lateral Swing Posture

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jian-Hua Qin ◽  
Jie Luo ◽  
Kai-Chi Chuang ◽  
Tian-Syung Lan ◽  
Lie-Ping Zhang ◽  
...  
Keyword(s):  
Static Stability ◽  
Quadruped Robot ◽  
Experimental Simulation ◽  
Upright Posture ◽  
Design And Optimization ◽  
Generalized Coordinates ◽  
The Stability ◽  
Leg Kinematics ◽  
Peak Value ◽  
Robot Body

Aiming at the problem that the stability of the quadruped robot is decreased as its leg momentum is too high, a stable balance adjustment structure of the quadruped robot based on the bionic lateral swing posture is proposed. First, the leg structure of the quadruped robot is improved and designed by using the mechanism of the lateral swing posture of the leg of the hoof animal. Then, the D-H method is used to construct the corresponding leg kinematics model and determine the generalized coordinates of the leg joints in the lateral swing posture. The torque expression of the quadruped robot when it is tilted is established. Based on the differential equation of momentum of the hip joint and its static stability analysis, the static stability conditions in the upright posture and the bionic lateral swing posture are given. Finally, the experimental simulation and comparative analysis of the upright posture and the lateral swing posture of the quadruped robot are proposed by using the Adams virtual prototype technology. The simulation results show that as the angle of lateral swing increases, the peak value of the positive flip torque of the quadruped robot body increases accordingly, while the degree of tilt decreases accordingly, which shows that the bionic lateral swing posture of the quadruped robot has higher static stability than the traditional upright posture. This research provides a technical reference for the design and optimization of the offline continuous gait of the robot and the improvement of stability.

scholarly journals Locomotion of Ants Walking up Slippery Slopes of Granular Materials

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
A Humeau ◽  
M Piñeirua ◽  
J Crassous ◽  
J Casas
Keyword(s):  
Material Properties ◽  
Granular Media ◽  
Gait Pattern ◽  
Gait Patterns ◽  
Solid Media ◽  
Manipulative Experiments ◽  
Particle Level ◽  
Abnormality Index ◽  
Discrete Nature ◽  
Leg Kinematics

Abstract Many insects encounter locomotory difficulties in walking up sand inclines. This is masterfully exploited by some species for building traps from which prey are rarely able to escape, as the antlion and its deadly pit. The aim of this work is to tear apart the relative roles of granular material properties and slope steepness on the insect leg kinematics, gait patterns, and locomotory stability. For this, we used factorial manipulative experiments with different granular media inclines and the ant Aphaenogaster subterranea. Our results show that its locomotion is similar on granular and solid media, while for granular inclined slopes we observe a loss of stability followed by a gait pattern transition from tripod to metachronal. This implies that neither the discrete nature nor the roughness properties of sand alone are sufficient to explain the struggling of ants on sandy slopes: the interaction between sand properties and slope is key. We define an abnormality index that allows us to quantify the locomotory difficulties of insects walking up a granular incline. The probability of its occurrence reveals the local slipping of the granular media as a consequence of the pressure exerted by the ant’s legs. Our findings can be extended to other models presenting locomotory difficulties for insects, such as slippery walls of urns of pitcher plants. How small arthropods walking on granular and brittle materials solve their unique stability trade-off will require a thorough understanding of the transfer of energy from leg to substrate at the particle level.

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