Modulation of Lower Limb Withdrawal Reflexes During Gait: A Topographical Study

2004 ◽  
Vol 91 (1) ◽  
pp. 258-266 ◽  
Author(s):  
Erika G. Spaich ◽  
Lars Arendt-Nielsen ◽  
Ole K. Andersen
Keyword(s):  
Electrical Stimulation ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Swing Phase ◽  
Hip Joints ◽  
Withdrawal Reflex ◽  
Heel Contact ◽  
Withdrawal Reflexes ◽  
A Site ◽  
Site Dependency

The aim of this study was to investigate the modulation and topography of the nociceptive withdrawal reflex elicited by painful electrical stimulation of the foot sole during gait. Fifteen healthy volunteers participated in this study. Cutaneous electrical stimulation was delivered on five locations of the foot sole after heel-contact, during foot-flat, after heel-off, and during the mid-swing phase of the gait cycle during treadmill walking. Reflexes were recorded from muscles of the ipsilateral and contralateral legs. Furthermore, the kinematic responses in the sagittal plane of the ipsilateral ankle, knee, and hip joints were recorded. Reflexes in the distal muscles showed a site-dependant modulation. The largest responses in tibialis anterior were evoked at the arch of the foot and the smallest at the heel ( P < 0.05). The largest soleus responses were also elicited at the arch of the foot ( P < 0.04). The EMG responses in flexors and extensors of the knee and extensors of the contralateral leg were generally not dependent on the stimulation site. The response at the three joints showed site dependency, especially during the swing phase where maximal flexion was obtained by stimulation at the arch of the foot ( P < 0.05). The withdrawal reflex was modulated during the gait cycle and presented distinctive characteristics for the different muscles studied. Minimal kinematic responses were observed during stance in contrast to swing phase. Modulation of the reflex probably ensures an appropriate withdrawal but primarily secures balance and continuity of movement.

scholarly journals Movement of the tibial end in a PTB prosthesis socket: A sagittal X-ray study of the PTB prosthesis

1993 ◽  
Vol 17 (1) ◽  
pp. 21-26 ◽  
Author(s):  
M. Lilja ◽  
T. Johansson ◽  
T. Öberg
Keyword(s):  
Gait Cycle ◽  
Soft Tissues ◽  
Sagittal Plane ◽  
Mean Value ◽  
Swing Phase ◽  
Patient Comfort ◽  
X Ray ◽  
Prosthetic Socket ◽  
Heel Contact ◽  
Prosthetic Fitting

To investigate the movement of the tibial end in the sagittal plane in the PTB prosthetic socket during a gait cycle, 7 patients with a median age of 72 years were examined using X-ray technique. The gait cycle was reduced to four different static positions: heel contact, mid-stance, push-off and swing phase. The mean value of tibial movement in the socket in the anteroposterior direction was 2.2 cm, in proximodistal direction 2.8 cm, and the total sagittal movement during the whole gait cycle was 7.5 cm. The results indicate that one factor affecting the magnitude of the movement was the prestretching of soft tissues. All the patients who experienced a good prosthetic fitting had their soft tissues prestretched. The extreme dorsal and proximal positions of the tibial end during the gait cycle was in the swing phase position. The extreme distal position occurred somewhere between mid-stance and push-off. The extreme anterior position of the tibial end was seen during heel contact. This study has shown the magnitude of the movements in a PTB socket during a simulated gait cycle. The study has given hints on factors affecting prosthetic fitting, and further research within this field might provide indications of how to optimise socket shape to give maximal patient comfort.

scholarly journals Newly designed computer controlled knee-ankle-foot orthosis (Intelligent Orthosis)

1998 ◽  
Vol 22 (3) ◽  
pp. 230-239 ◽  
Author(s):  
T. Suga ◽  
O. Kameyama ◽  
R. Ogawa ◽  
M. Matsuura ◽  
H. Oka
Keyword(s):  
Lower Limb ◽  
Stance Phase ◽  
Gait Cycle ◽  
Normal Subjects ◽  
Swing Phase ◽  
Ankle Foot Orthosis ◽  
Normal Gait ◽  
Heel Contact ◽  
Computer Controlled ◽  
Foot Orthosis

The authors have developed a knee-ankle-foot orthosis with a joint unit that controls knee movements using a microcomputer (Intelligent Orthosis). The Intelligent Orthosis was applied to normal subjects and patients, and gait analysis was performed. In the gait cycle, the ratio of the stance phase to the swing phase was less in gait with the knee locked using a knee-ankle-foot orthosis than in gait without an orthosis or gait with the knee controlled by a microcomputer. The ratio of the stance phase to the swing phase between controlled gait and normal gait was similar. For normal subjects the activity of the tibialis anterior was markedly increased from the heel-off phase to the swing phase in locked gait. The muscle activities of the lower limb were lower in controlled force in locked gait showed spikes immediately after heel-contact in the vertical at heel-contact in the sagittal to locked gait, gait with the Intelligent Orthosis is smooth and close to normal gait from the viewpoint of biomechanics. Even in patients with muscle weakness of the quadriceps, control of the knee joint using the Intelligent Orthosis resulted in a more smooth gait with low muscle discharge.

scholarly journals Genetic Algorithms Based Approach for Designing Spring Brake Orthosis – Part I: Spring Parameters

2012 ◽  
Vol 9 (3) ◽  
pp. 303-316 ◽  
Author(s):  
M. S. Huq ◽  
M. O. Tokhi
Keyword(s):  
First Principles ◽  
Knee Flexion ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Swing Phase ◽  
Full Extension ◽  
Torsion Spring ◽  
Constant Torque ◽  
Spring Type ◽  
Hip Flexion

Spring brake orthosis (SBO) concentrates purely on the knee to generate the swing phase of the paraplegic gait with the required hip flexion occurring passively as a consequence of the ipsilateral knee flexion, generated by releasing the torsion spring mounted at the knee joint. Electrical stimulation then drives the knee back to full extension, as well as restores the spring potential energy. In this paper, genetic algorithm (GA) and its variant multi-objective GA (MOGA) is used to perform the search operation for the ‘best’ spring parameters for the SBO spring mounted on an average sized subject simulated in the sagittal plane. Conventional torsion spring is tested against constant torque type spring in terms of swing duration as, based on first principles, it is hypothesized that constant torque spring would be able to produce slower SBO swing phase as might be preferred in assisted paraplegic gait. In line with the hypothesis, it is found that it is not possible to delay the occurrence of the flexion peak of the SBO swing phase further than its occurrence in the natural gait. The use of conventional torsion spring causes the swing knee flexion peak to appear rather faster than that of the natural gait, resulting in a potentially faster swing phase and hence gait cycle. The constant torque type spring on the other hand is able to stretch duration of the swing phase to some extent, rendering it the preferable spring type in SBO.

Ankle Bracing Alters Coordination and Coordination Variability in Individuals With and Without Chronic Ankle Instability

2021 ◽  
Vol 30 (1) ◽  
pp. 62-69
Author(s):  
Adam E. Jagodinsky ◽  
Christopher Wilburn ◽  
Nick Moore ◽  
John W. Fox ◽  
Wendi H. Weimar
Keyword(s):  
Lower Extremity ◽  
Gait Cycle ◽  
Relative Phase ◽  
Sagittal Plane ◽  
Ankle Instability ◽  
Chronic Ankle Instability ◽  
Swing Phase ◽  
Coordination Dynamics ◽  
Ankle Brace ◽  
Ankle Bracing

Context: Ankle bracing is an effective form of injury prophylaxis implemented for individuals with and without chronic ankle instability, yet mechanisms surrounding bracing efficacy remain in question. Ankle bracing has been shown to invoke biomechanical and neuromotor alterations that could influence lower-extremity coordination strategies during locomotion and contribute to bracing efficacy. Objective: The purpose of this study was to investigate the effects of ankle bracing on lower-extremity coordination and coordination dynamics during walking in healthy individuals, ankle sprain copers, and individuals with chronic ankle instability. Design: Mixed factorial design. Setting: Laboratory setting. Participants: Forty-eight recreationally active individuals (16 per group) participated in this cross-sectional study. Intervention: Participants completed 15 trials of over ground walking with and without an ankle brace. Main Outcome Measures: Coordination and coordination variability of the foot–shank, shank–thigh, and foot–thigh were assessed during stance and swing phases of the gait cycle through analysis of segment relative phase and relative phase deviation, respectively. Results: Bracing elicited more synchronous, or locked, motion of the sagittal plane foot–shank coupling throughout swing phase and early stance phase, and more asynchronous motion of remaining foot–shank and foot–thigh couplings during early swing phase. Bracing also diminished coordination variability of foot–shank, foot–thigh, and shank–thigh couplings during swing phase of the gait cycle, indicating greater pattern stability. No group differences were observed. Conclusions: Greater stability of lower-extremity coordination patterns as well as spatiotemporal locking of the foot–shank coupling during terminal swing may work to guard against malalignment at foot contact and contribute to the efficacy of ankle bracing. Ankle bracing may also act antagonistically to interventions fostering functional variability.

Functional Data Analyses for the Assessment of Joint Power Profiles During Gait of Stroke Subjects

2014 ◽  
Vol 30 (2) ◽  
pp. 348-352 ◽  
Author(s):  
André G. P. Andrade ◽  
Janaine C. Polese ◽  
Leopoldo A. Paolucci ◽  
Hans-Joachim K. Menzel ◽  
Luci F. Teixeira-Salmela
Keyword(s):  
Power Generation ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Plantar Flexion ◽  
Knee Extension ◽  
Mathematical Function ◽  
Joint Power ◽  
Gait Biomechanics ◽  
Isolated Points ◽  
Parametric Analyses

Lower extremity kinetic data during walking of 12 people with chronic poststroke were reanalyzed, using functional analysis of variance (FANOVA). To perform the FANOVA, the whole curve is represented by a mathematical function, which spans the whole gait cycle and avoids the need to identify isolated points, as required for traditional parametric analyses of variance (ANOVA). The power variables at the ankle, knee, and hip joints, in the sagittal plane, were compared between two conditions: With and without walking sticks at comfortable and fast speeds. For the ankle joint, FANOVA demonstrated increases in plantar flexion power generation during 60–80% of the gait cycle between fast and comfortable speeds with the use of walking sticks. For the knee joint, the use of walking sticks resulted in increases in the knee extension power generation during 10–30% of the gait cycle. During both speeds, the use of walking sticks resulted in increased power generation by the hip extensors and flexors during 10–30% and 40–70% of the gait cycle, respectively. These findings demonstrated the benefits of applying the FANOVA approach to improve the knowledge regarding the effects of walking sticks on gait biomechanics and encourage its use within other clinical contexts.

Tracking ankle joint movements during gait cycle via control of functional electrical stimulation

2021 ◽  
pp. 095441192110523
Author(s):  
Seyyed Arash Haghpanah ◽  
Morteza Farrokhnia ◽  
Sajjad Taghvaei ◽  
Mohammad Eghtesad ◽  
Esmaeal Ghavanloo
Keyword(s):  
Electrical Stimulation ◽  
Ankle Joint ◽  
Functional Electrical Stimulation ◽  
Gait Cycle ◽  
Sliding Mode ◽  
Musculoskeletal Model ◽  
Pd Controller ◽  
Model Errors ◽  
Nonlinear Method ◽  
Cycle Simulation

Functional electrical stimulation (FES) is an effective method to induce muscle contraction and to improve movements in individuals with injured central nervous system. In order to develop the FES systems for an individual with gait impairment, an appropriate control strategy must be designed to accurate tracking performance. The goal of this study is to present a method for designing proportional-derivative (PD) and sliding mode controllers (SMC) for the FES applied to the musculoskeletal model of an ankle joint to track the desired movements obtained by experiments on two healthy individuals during the gait cycle. Simulation results of the developed controller on musculoskeletal model of the ankle joint illustrated that the SMC is able to track the desired movements more accurately than the PD controller and prevents oscillating patterns around the experimentally measured data. Therefore, the sliding mode as the nonlinear method is more robust in face to unmodeled dynamics and model errors and track the desired path smoothly. Also, the required control effort is smoother in SMC with respect to the PD controller because of the nonlinearity.

Liquid State Machine to Generate the Movement Profiles for the Gait Cycle of a 6 DOF Bipedal Robot in a Sagittal Plane

2018 ◽  
Author(s):  
Jesús Franco-Robles ◽  
Alejandro De Lucio-Rangel ◽  
Karla A. Camarillo-Gómez ◽  
Gerardo I. Pérez-Soto ◽  
Jesús Rivera-Guillén
Keyword(s):  
Time Series ◽  
Multilayer Perceptron ◽  
Liquid State ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Experimental Result ◽  
Forward Kinematics ◽  
Neuronal System ◽  
Bipedal Robot ◽  
Input Time

In this paper, a neuronal system with the ability to generate motion profiles and profiles of the ZMP in a 6DoF bipedal robot in the sagittal plane, is presented. The input time series for LSM training are movement profiles of the oscillating foot trajectory obtained by forward kinematics performed by a previously trained ANN multilayer perceptron. The profiles of objective movement for training are acquired from the analysis of the human walk. Based on a previous simulation of the bipedal robot, a profile of the objective ZMP will be generated for the y–axis and another for the z–axis to know its behavior during the training walk. As an experimental result, the LSM generates new motion profiles and ZMP, given a different trajectory with which it was trained. With the LSM it will be possible to propose new trajectories of the oscillating foot, where it will be known if this trajectory will be stable, by the ZMP, and what movement profile for each articulation will be required to reach this trajectory.

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