scholarly journals Effects of alignment variables on thigh axial torque during swing phase in AK amputee gait

1983 ◽  
Vol 7 (1) ◽  
pp. 41-47 ◽  
Author(s):  
G. Ishai ◽  
A. Bar ◽  
Z. Susak
Keyword(s):  
Stance Phase ◽  
Optimization Procedure ◽  
Swing Phase ◽  
Clinical Tool ◽  
Factors Associated ◽  
Optimum Choice ◽  
And Performance ◽  
Socket Interface ◽  
Amputee Gait

It is suggested that a major source of discomfort for above-knee amputees during the swing phase of walking, is the thigh axial torque (TAT) transferred at the stump-socket interface. The relation between TAT and variations in its six relevant alignment adjustments, has been investigated. A computerized routine has been established which indicates optimum choice of alignment setting, based on minimal TAT peaks. Feasibility for attenuating swing phase TAT has been demonstrated in three simulated patterns of amputee gait. As a conclusion, it is suggested that a useful clinical tool could be based on the presented alignment optimization procedure and may be expanded to include other factors associated with swing and stance phase comfort and performance.

A New Stance Control Knee Orthosis Using a Self-Locking Mechanism Based on a Planetary Gear Train

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Gaspar Rodríguez Jiménez ◽  
David Rodríguez Salgado ◽  
Francisco Javier Alonso Sanchez ◽  
Jose María del Castillo Granados
Keyword(s):  
Stance Phase ◽  
Planetary Gear ◽  
Swing Phase ◽  
Gear Train ◽  
Planetary Gear Train ◽  
External Agent ◽  
Locking Mechanism ◽  
Control Knee ◽  
And Performance ◽  
Knee Orthosis

The objective of this work was to design and build a fully mechanical knee orthosis. A knee orthosis should both allow control of the angle of flexion of the knee during the stance phase of the gait cycle and leave the joint free during the swing phase. Knee orthoses are normally used to assist the walking of people suffering from muscle weaknesses or gait pathologies in order to avoid excessive knee flexion during the stance phase. The design of the orthosis proposed in the present work is characterized by allowing the knee to be locked at any angle of flexion during the stance phase, and because the orthosis can be unlocked to allow the joint to be released in the swing phase without the action of any external agent, i.e., without requiring external electrical or electronic systems for the control and performance of the orthosis. These characteristics mean that the design can be adapted to the gait of any user. The proposed design consists of a set of three rods, one attached to the user's thigh, another to the calf, and the other to the foot, connected to each other by a self-locking planetary gear train (PGT).

scholarly journals Developmental constraints of quadrupedal coordination across crawling styles in human infants

2012 ◽  
Vol 107 (11) ◽  
pp. 3050-3061 ◽  
Author(s):  
Susan K. Patrick ◽  
J. Adam Noah ◽  
Jaynie F. Yang
Keyword(s):  
Nervous System ◽  
Stance Phase ◽  
Swing Phase ◽  
Interlimb Coordination ◽  
Young Age ◽  
Developmental Constraints ◽  
Human Infants ◽  
Coordination Patterns ◽  
Duration Of Cycle ◽  
Developing Nervous System

Human infants can crawl using several very different styles; this diversity appears at first glance to contradict our previous findings from hands-and-knees crawling, which suggested that there were strict limitations on coordination, imposed either mechanically or by the developing nervous system. To determine whether coordination was similarly restricted across crawling styles, we studied free crawling overground in 22 infants who used a number of different locomotor strategies. Despite the wide variety in the use of individual limbs and even the number of limbs used, the duration of the stance phase increased with duration of cycle, whereas the duration of the swing phase remained more constant. Additionally, all infants showed organized, rhythmic interlimb coordination. Alternating patterns (e.g., trotlike) predominated (86% of infants). Alternatively, yet much less frequently, all limbs used could work in synchrony (14% of infants). Pacelike patterns were never observed, even in infants that crawled with the belly remaining in contact with the ground so that stability was not a factor. To explore the robustness of the interlimb coordination, a perturbation that prolonged swing of the leg was imposed on 14 additional infants crawling on hands and knees overground or on the treadmill. The perturbation led to a resetting of the crawling pattern, but never to a change in the coordination of the limbs. The findings concur with those regarding other infant animals, together suggesting that the nervous system itself limits the coordination patterns available at a young age.

Central connections of sensory neurones from a hair plate proprioceptor in the thoraco-coxal joint of the locust.

1995 ◽  
Vol 198 (7) ◽  
pp. 1589-1601 ◽  
Author(s):  
F Kuenzi ◽  
M Burrows
Keyword(s):  
Stance Phase ◽  
Swing Phase ◽  
Motor Neurone ◽  
Sensory Neurone ◽  
Sensory Neurones ◽  
Selective Stimulation ◽  
Basal Joint ◽  
Motor Neurones ◽  
Individual Motor ◽  
Stimulation Of

The hair plate proprioceptors at the thoraco-coxal joint of insect limbs provide information about the movements of the most basal joint of the legs. The ventral coxal hair plate of a middle leg consists of group of 10-15 long hairs (70 microns) and 20-30 short hairs (30 microns). The long hairs are deflected by the trochantin as the leg is swung forward during the swing phase of walking, and their sensory neurones respond phasically during an imposed deflection and tonically if the deflection is maintained. Selective stimulation of the long hairs elicits a resistance reflex that rotates the coxa posteriorly and is similar to that occurring at the transition from the swing to the stance phase of walking. The motor neurones innervating the posterior rotator and adductor coxae muscles are excited, and those to the antagonistic anterior rotator muscle are inhibited. By contrast, selective stimulation of the short hairs leads only to a weak inhibition of the anterior rotator. The excitatory effects of the long hairs are mediated, in part, by direct connections between their sensory neurones and particular motor neurones. A spike in a sensory neurone elicits a short-latency depolarising postsynaptic potential (PSP) in posterior rotator and adductor motor neurones whose amplitude is enhanced by hyperpolarising current injected into the motor neurone. When the calcium in the saline is replaced with magnesium, the amplitude of the PSP is reduced gradually, and not abruptly as would be expected if an interneurone were interposed in the pathway. Several sensory neurones from long hairs converge to excite an individual motor neurone, evoking spikes in some motor neurones. The projections of the sensory neurones overlap with some of the branches of the motor neurones in the lateral association centre of the neuropile. It is suggested that these pathways would limit the extent of the swing phase of walking and contribute to the switch to the stance phase in a negative feedback loop that relieves the excitation of the hairs by rotating the coxa backwards.

scholarly journals ROLE OF HAMSTRING MUSCLES IN KNEE JOINT STABILITY PROVIDING AND INJURY PREVENTION

2016 ◽  
Vol 3 ◽  
pp. 522
Author(s):  
Inese Pontaga
Keyword(s):  
Stance Phase ◽  
Knee Extension ◽  
Swing Phase ◽  
Joint Stability ◽  
Distance Runners ◽  
Leg Extension ◽  
Hamstring Muscles ◽  
Extreme Extension ◽  
Torque Values

The aim of our investigation was to determine the ratio of maximal torque values and the torques in the certain positions of range of movements (ROM) between hamstring (H) and quadriceps femoris (Q) muscles at medium and high velocity of movement in concentric (CC) and eccentric (ECC) action of hamstring muscles. The knee muscles of 15 amateur female short and middle distance runners were tested by the dynamometer system in the isokinetic movements with the angular velocity of 90º/s and 240º/s in CC and at the velocity of 90º/s in ECC H/ CC Q muscles contractions. The torque values produced by the muscles are detected at the different angular positions of the ROM with the step of 10º. The ratios of H/ Q muscles torques are calculated. The H/Q muscles maximal torques ratio is 0.51 ± 0.13 at the velocity of 90º/s in CC and 0.60 ± 0.09 in ECC H/ CC Q muscles contractions, and 0.59 ± 0.09 CC at the velocity of 240º/s. The H/Q maximal torques ratio and this ratio in the knee extreme extension and flexion at the ECC contraction of H is higher due to greater torques produced by the H in comparison with Q muscle. The H must be stronger to decelerate the thigh and lower leg extension in the late swing phase of running and to extend the hip in early stance phase to provide powerful sprint running and prevent the knee and H injury. The H/Q muscles torques ratio in extended knee positions are similar in medium (90º/s) and fast (240º/s) velocity of motions because CC action of H muscles cannot prevent extreme knee extension.

Activity of spindle afferents from cat anterior thigh muscles. II. Effects of fusimotor blockade

1985 ◽  
Vol 54 (3) ◽  
pp. 565-577 ◽  
Author(s):  
G. E. Loeb ◽  
J. A. Hoffer
Keyword(s):  
Stance Phase ◽  
Femoral Nerve ◽  
Knee Extensor ◽  
Muscle Spindles ◽  
Swing Phase ◽  
Knee Extensors ◽  
Electromyographic Activity ◽  
Force Output ◽  
Anterior Thigh ◽  
Proprioceptive Signal

Chronically implanted electrodes and nerve cuff catheters were used to record the activity of individual muscle spindle afferents during treadmill walking as low doses of lidocaine were infused around the femoral nerve to progressively block gamma motoneuron activity. Both primary and secondary endings from both the monarticular knee extensors and the biarticular hip/knee muscles of the anterior thigh showed large decreases in afferent activity, usually well before changes in the electromyographic activity, force output, or length and velocity were seen in the parent muscles. This decline in the proprioceptive signal feeding back onto the spinal cord, which we presume to have involved most of the spindles supplied by the femoral nerve, did not cause noticeable irregularities or instability of the walking gait. At the peak of the fusimotor blockade, spindle afferents from knee extensor muscles lost about half of their usually brisk activity during the near-isometric contraction of the stance phase. Significant decreases in the response to passive stretch during the flexion phase also occurred. At the peak of the fusimotor blockade, spindle afferents from the biarticular muscles lost all of their activity during the rapidly shortening swing phase and about half of their activity during the rapidly lengthening stance phase. For both monarticular and biarticular muscle spindles, the activity decreases in stance and swing phase often occurred at distinctly different stages of the progressive fusimotor blockade, indicating several different sources of fusimotor control. From these data, we infer that the sensitivity of most spindle afferents is substantially influenced by fusimotor activity during phases of both extrafusal activity and extrafusal silence. At least some of this influence appears to come from fusimotor neurons whose recruitment is independent of the extrafusal recruitment. The extent and type of fusimotor effects on spindle afferent sensitivity (dynamic or static) appear to be specialized for the mechanical events that tend to occur during those phases.

scholarly journals Evaluation of a Torque-Driven Model of Jumping for Height

2006 ◽  
Vol 22 (4) ◽  
pp. 264-274 ◽  
Author(s):  
Mark A. King ◽  
Cassie Wilson ◽  
Maurice R. Yeadon
Keyword(s):  
Optimization Procedure ◽  
Computer Simulation Model ◽  
Joint Angles ◽  
Strength Parameters ◽  
Kinematic Data ◽  
Percentage Difference ◽  
The Difference ◽  
Height Increase ◽  
And Performance ◽  
Recorded Performance

This study used an optimization procedure to evaluate an 8-segment torque-driven subject-specific computer simulation model of the takeoff phase in running jumps for height. Kinetic and kinematic data were obtained on a running jump performed by an elite male high jumper. Torque generator activation timings were varied to minimize the difference between simulation and performance in terms of kinematic and kinetic variables subject to constraints on the joint angles at takeoff to ensure that joints remained within their anatomical ranges of motion. A percentage difference of 6.6% between simulation and recorded performance was obtained. Maximizing the height reached by the mass center during the flight phase by varying torque generator activation timings resulted in a credible height increase of 90 mm compared with the matching simulation. These two results imply that the model is sufficiently complex and has appropriate strength parameters to give realistic simulations of running jumps for height.

scholarly journals H-Reflex Modulation During Walking in Spastic Paretic Subjects

1991 ◽  
Vol 18 (4) ◽  
pp. 443-452 ◽  
Author(s):  
J.F. Yang ◽  
J. Fung ◽  
M. Edamura ◽  
R. Blunt ◽  
R.B. Stein ◽  
...  
Keyword(s):  
Tibialis Anterior ◽  
Stance Phase ◽  
Normal Subjects ◽  
Swing Phase ◽  
H Reflex ◽  
Reflex Modulation ◽  
Healthy Individuals ◽  
Step Cycle ◽  
Common Pattern ◽  
Slight Depression

ABSTRACT:Hoffmann (H) reflexes were elicited from the soleus muscle during treadmill walking in 21 spastic paretic patients. The soleus and tibialis anterior muscles were reciprocally activated during walking in most patients, much like that observed in healthy individuals. The pattern of H-reflex modulation varied considerably between patients, from being relatively normal in some patients to a complete absence of modulation in others. The most common pattern observed was a lack of H-reflex modulation through the stance phase and slight depression of the reflex in the swing phase, considerably less modulation than that of normal subjects under comparable walking conditions. The high reflex amplitudes during periods of the step cycle such as early stance seems to be related to the stretch-induced large electromyogram bursts in the soleus in some subjects. The abnormally active reflexes appear to contribute to the clonus encountered during walking in these patients. In three patients who were able to walk for extended periods, the effect of stimulus intensity was examined. Two of these patients showed a greater degree of reflex modulation at lower stimulus intensities, suggesting that the lack of modulation observed at higher stimulus intensities is a result of saturation of the reflex loop. In six other patients, however, no reflex modulation could be demonstrated even at very low stimulus intensities.

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 Knee mechanisms for through-knee prostheses

1983 ◽  
Vol 7 (2) ◽  
pp. 107-112 ◽  
Author(s):  
K. Öberg
Keyword(s):  
Stance Phase ◽  
Stability Diagram ◽  
Phase Control ◽  
Swing Phase ◽  
Control Mechanisms ◽  
Knee Prostheses ◽  
Heavy Duty ◽  
Linkage Mechanism ◽  
The Stability

The most widely used knee mechanisms for through-knee amputees can be characterized as three principal types of design. These types are metal side bars with heavy duty joints, conventional knee mechanisms for above-knee amputees and special polycentric linkage mechanisms for through-knee amputees. An investigation in Sweden in 1979 showed that over 50% of the fittings were using the special polycentric linkage mechanisms for through-knee amputees. The stability diagram illustrates how voluntary and involuntary stability can be utilized by using different polycentric linkage mechanisms for through-knee amputees. The polycentric linkage mechanism can be designed for different stance phase characteristics as well as incorporation of different swing phase control mechanisms. The cosmesis of the available designs is acceptable but there is need for lighter and more compact designs especially for the young and small amputee.

scholarly journals Effect of Kinesio Taping on the Walking Ability of Patients with Foot Drop after Stroke

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Yilan Sheng ◽  
Shifeng Kan ◽  
Zixing Wen ◽  
Wenhua Chen ◽  
Qi Qi ◽  
...  
Keyword(s):  
Stride Length ◽  
Stance Phase ◽  
Swing Phase ◽  
Foot Drop ◽  
Control Group ◽  
Walking Ability ◽  
Timed Up And Go ◽  
Kinesio Taping ◽  
Analysis System ◽  
Experimental Group

Objective. The purpose of this study was to investigate the effect of kinesio taping on the walking ability in patients with foot drop after stroke. Methods. Sixty patients were randomly divided into the experimental group (with kinesio taping) and the control group (without kinesio taping). The 10-Meter Walking Test (10MWT), Timed Up and Go Test (TUGT), stride length, stance phase, swing phase, and foot rotation of the involved side were measured with the German ZEBRIS gait running platform analysis system and were used to evaluate and compare the immediate effects of kinesio taping. All the measurements were made in duplicate for each patient. Results. The demographic variables of patients in both groups were comparable before the treatment (p>0.05). After kinesio taping treatment, significant improvement was found in the 10MWT and the TUGT for patients in the experimental group (p<0.05). There were significant differences in the 10MWT and TUGT between the experimental and control groups after treatment (p<0.05). In terms of gait, we found significant improvement in stride length (p<0.001), stance phase (p<0.001), swing phase (p<0.001), and foot rotation (p<0.001) of the involved side in experimental group after treatment compared with those before treatment. Further, the functional outcomes and gait ability were significantly improved in the experimental group after treatment (p<0.05), compared to the control group. Conclusion. Kinesio taping can immediately improve the walking function of patients with foot drop after stroke.

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