scholarly journals The role of the supporting lower limb function in the premotor changes in the H-reflex of m. soleus

2016 ◽  
Vol 7 (1) ◽  
pp. 43-47
Author(s):  
E. Z. Ivanchenko
Keyword(s):  
Ankle Joint ◽  
Soleus Muscle ◽  
Lower Limb ◽  
Time Course ◽  
Standing Position ◽  
H Reflex ◽  
Lower Limbs ◽  
Emg Activity ◽  
Spinal Neuron ◽  
Healthy Humans

In studies on healthy humans we examined changes in the H reflex amplitude and the intensity of background EMG of the soleus muscle within the premotor period of voluntary extension of the contralateral ankle joint. The tested persons were in the lying prone position with relaxed legs, or in the standing position with support on both feet or only on one foot with additional hand support. The soleus H reflex was induced using the standard technique by transcutaneous stimulation (1 ms long current pulses) of the tibial nerve afferents in the region of the popliteal dimple. Using superficial electrodes, we recorded the integral EMG reflex discharge from the m. soleus, amplified, and visualized it using a two-channel digital oscillograph, Handiscope HS3 (TiePieEngeneering, Netherlands). In other tests, we also recorded tonic background EMG activity from the soleus muscle. After fullwave rectification and low-frequency filtration we estimated the area under the integral curve enveloping oscillations of the above mentioned EMG. In the lying position the extension of contralateral ankle joint evoked anticipatory facilitation of the testing soleus H-reflex. It manifested in 90–60 ms and reached the maximum 30 ms before the conditioning movement. Considerable changes of the soleus background EMG-activity did not occur during the premotor period. Consequently, it is supposed that the mechanism leading to the H-reflex facilitation is the decrease of presynaptic inhibition at 1a. In the standing position with support on both feet contralateral ankle joint extension caused anticipatory inhibition of the soleus H-reflex and simultaneous suppression of background EMG 90–60 ms before the conditioning movement. These results indicate the anticipatory changes of muscle tone and suggest participation of postsynaptic mechanism in the inhibition of the testing H-reflex. When the moving contralateral extremity had no support, the contralateral ancle joint extension did not cause anticipatory inhibition but facilitation of the soleus H-reflex. Its time course was similar to that observed in the lying position. The considerable changes of the soleus background EMG-activity did not arise. The results of the experiments indicate that the nature of premotor changes in the spinal neuron circuits, associated with the lower limb muscles, depends not only on the type of upcoming voluntary movement. Being caused by the contralateral limb movements, they depend greatly on the fulfillment or nonfulfillment of the support function by the lower limbs.

Mechanism of thixotropic behavior at relaxed joints in the rat

1987 ◽  
Vol 62 (4) ◽  
pp. 1615-1621 ◽  
Author(s):  
A. W. Wiegner
Keyword(s):  
Ankle Joint ◽  
Soleus Muscle ◽  
Short Range ◽  
Time Course ◽  
Muscle Length ◽  
Muscle Preparation ◽  
Pentobarbital Sodium ◽  
Stiffness Properties ◽  
Thixotropic Behavior ◽  
Human Joints

When a relaxed joint is subjected to a small sinusoidal torque, the amplitude of the steady-state displacement response is increased up to severalfold by a transient larger perturbation. The original state, in which the relaxed joint is unexpectedly stiff, is restored by several seconds of inactivity. This thixotropic phenomenon has previously been observed in a variety of human joints. We have now investigated the mechanism of thixotropic behavior at relaxed joints in rats anesthetized with pentobarbital sodium, by using a series of preparations including the intact ankle joint, a blood-perfused soleus muscle preparation, an isolated soleus muscle, and ankle joint isolated by severing all muscular attachments. Thixotropic behavior was observed in all intact, isolated muscle, and isolated joint preparations. The contribution of the joint to thixotropic behavior was comparable to, and at times exceeded, the contribution of muscle. We also analyzed the short-range stiffness properties of relaxed, blood-perfused soleus muscles and found them to be similar to thixotropy with respect to range of action (0.2–0.3% of muscle length), elastic modulus (approximately 4 kg/cm2), and time course for redevelopment (time constant = 2.5 s at 34 degrees C). Thus thixotropic behavior at a relaxed joint may be attributed both to the joint structures and to short-range stiffness of muscles acting at the joint.

Efekty ćwiczeń zwiększających ruchomość stawów kończyn dolnych u mężczyzn po 60. roku życia

2019 ◽  
Vol 22 (1) ◽  
Author(s):  
Małgorzata Nyc ◽  
Jarosław Fugiel ◽  
Tomasz Ignasiak ◽  
Anna Rohan
Keyword(s):  
Physical Exercise ◽  
Ankle Joint ◽  
Lower Limb ◽  
Exercise Programme ◽  
Lower Limbs ◽  
Joint Mobility ◽  
Functional Capability ◽  
Systematic Practice

Aging is accompanied by multiple changes, including articular degeneration and limited articular mobility, which may cause pain. Functional capability in a senior age is crucial to ensure the comfort of life for as long as possible. Therefore, it is important to take actions to maintain the proper range of mobility in the joints. Systematic practice of properly selected exercises is one of such methods. The aim of the research was to assess the effects of a physical exercise programme used in men over 60 years of age. The study was conducted in a group of men between 60 and 75 years of age. All participants took part in a 6-week exercise programme. The range of lower limb joint mobility was assessed at baseline and after exercise programme completion. The results obtained indicate that the proposed exercise programme contributed to increased joint mobility in both lower limbs. Statistically significant differences were found for all types of movements except for flexion in the ankle joint. The 6-week exercise programme seems sufficient to increase articular mobility in men over 60 years of age

Push recovery control for the underactuated lower extremity exoskeleton based on improved capture point concept

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jiaqi Zhang ◽  
Ming Cong ◽  
Dong Liu ◽  
Yu Du ◽  
Hongjiang Ma
Keyword(s):  
Lower Extremity ◽  
Ankle Joint ◽  
Lower Limb ◽  
Biped Robot ◽  
Lower Limbs ◽  
Simple Method ◽  
Content Type ◽  
Torsion Spring ◽  
Balance Ability ◽  
Capture Point

Purpose The purpose of this paper is to use a simple method to enhance the ability of lower limb exoskeletons to restore balance under large interference conditions and to solve the problem that biped robot stability criterion cannot be fully applied to the underactuated lower limb exoskeletons. Design/methodology/approach The method used in this paper is to construct an underactuated lower extremity exoskeleton ankle joint with a torsion spring. Based on the constructed exoskeleton, the linear inverted torsion spring pendulum model is proposed, and the traditional capture point (CP) concept is optimized. Findings The underactuated exoskeleton ankle joint with torsion springs, combined with the improved CP concept, can effectively reduce the forward stepping distance under the same interference condition, which is equivalent to enhancing the balance ability of the lower extremity exoskeleton. Originality/value The contribution of this paper is to enhance the balance ability of the exoskeleton of the lower limbs under large interference conditions. The torsion spring is used as the exoskeleton ankle joint, and the traditional CP concept is optimized according to the constructed exoskeleton.

Condition of the soleus muscle center of the immobilized human limb

1982 ◽  
Vol 63 (2) ◽  
pp. 47-49
Author(s):  
I. N. Pleshchinsky ◽  
V. I. Alatyrev ◽  
S. A. Yunaleeva ◽  
L. G. Khasanova ◽  
M. S. Davydova ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Soleus Muscle ◽  
Lower Limb ◽  
The State ◽  
H Reflex ◽  
Recurrent Inhibition ◽  
Intact Side ◽  
Reflex Excitability ◽  
Human Limb

The effect of immobilization of the lower limb on the state of the soleus muscle center and its electrical activity was studied. Using the H-reflex technique, a decrease in the reflex excitability of motoneurons and an increase in recurrent inhibition on the immobilization side compared to the intact side were established. A decrease in the amplitude of the M-response of the immobilized soleus muscle was also found.

scholarly journals Relationship between upper and lower limb conduit artery vasodilator function in humans

2011 ◽  
Vol 111 (1) ◽  
pp. 244-250 ◽  
Author(s):  
Dick H. J. Thijssen ◽  
Nicola Rowley ◽  
Jaume Padilla ◽  
Grant H. Simmons ◽  
M. Harold Laughlin ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Femoral Artery ◽  
Brachial Artery ◽  
Superficial Femoral Artery ◽  
Popliteal Artery ◽  
Lower Limb ◽  
Strong Predictor ◽  
Lower Limbs ◽  
Conduit Artery ◽  
Healthy Humans

Brachial artery flow-mediated dilation (FMD) is a strong predictor of future cardiovascular disease and is believed to represent a “barometer” of systemic endothelial health. Although a recent study [Padilla et al. Exp Biol Med (Maywood) 235: 1287–1291, 2010] in pigs confirmed a strong correlation between brachial and femoral artery endothelial function, it is unclear to what extent brachial artery FMD represents a systemic index of endothelial function in humans. We conducted a retrospective analysis of data from our laboratory to evaluate relationships between the upper (i.e., brachial artery) vs. lower limb (superficial femoral n = 75; popliteal artery n = 32) endothelium-dependent FMD and endothelium-independent glyceryl trinitrate (GTN)-mediated dilation in young, healthy individuals. We also examined the relationship between FMD assessed in both brachial arteries ( n = 42). There was no correlation between brachial and superficial femoral artery FMD ( r2 = 0.008; P = 0.46) or between brachial and popliteal artery FMD ( r2 = 0.003; P = 0.78). However, a correlation was observed in FMD between both brachial arteries ( r2 = 0.34; P < 0.001). Brachial and superficial femoral artery GTN were modestly correlated ( r2 = 0.13; P = 0.007), but brachial and popliteal artery GTN responses were not ( r2 = 0.08; P = 0.11). Collectively, these data indicate that conduit artery vasodilator function in the upper limbs (of healthy humans) is not predictive of that in the lower limbs, whereas measurement of FMD in one arm appears to be predictive of FMD in the other. These data do not support the hypothesis that brachial artery FMD in healthy humans represents a systemic index of endothelial function.

scholarly journals Impact of Self-Selected Customized Orthotics on Lower Limbs Biomechanics

2021 ◽  
Author(s):  
Benjamin Dourthe ◽  
Judith Osterloh ◽  
Vinzenz Von Tscharner ◽  
Sandro Nigg ◽  
Benno M. Nigg
Keyword(s):  
Isometric Contraction ◽  
Lower Limb ◽  
Statistical Significance ◽  
Lower Limbs ◽  
Patient Specific ◽  
Emg Activity ◽  
Post Intervention ◽  
Walking Intervention ◽  
Foot Arch ◽  
The Impact

Customized insoles are commonly prescribed to prevent or treat a variety of foot pathologies and to reduce foot and lower limb fatigue. Due to the patient-specific design and production of such orthotics, the concept of self-selected customized orthotics (SSCO) has recently been developed. The goal of this study was to assess the impact of SSCO technology on several physiological and biomechanical variables during uphill power walking. Thirty male participants underwent an uphill power walking intervention at constant speed in two insoles conditions (control and SSCO). The electromyographic (EMG) activity of their right gastrocnemii and vastii muscles was measured. Perceived fatigue was assessed every 5 minutes and the intervention stopped when the targeted fatigue level was reached. Baseline and post-intervention assessments were also performed. Sixty-three percent of the participants experienced an improvement in foot fatigue while wearing the SSCO. The foot arch seemed to collapse less when participants wore the SSCO, but statistical significance was not reached. The changes in mean EMG activity was not consistent between the 50% isometric contraction and the walking trial. In conclusion, while some interesting trends were observed when wearing SSCO, further investigations should be performed to try and reach statistical significance.

scholarly journals Lower limb symmetry index (LLSI) pre- and post-reconstruction of the ACL: a controlled study

2020 ◽  
pp. 1-6
Author(s):  
Luma Soares Lustosa ◽  
Nyck Douglas Claro Pereira ◽  
José Jamacy de Almeida Ferreira ◽  
Palloma Rodrigues de Andrade ◽  
Heleodório Honorato dos Santos
Keyword(s):  
Lower Limb ◽  
Knee Extension ◽  
Lower Limbs ◽  
Controlled Study ◽  
Knee Extensors ◽  
Emg Activity ◽  
Symmetry Index ◽  
Limb Symmetry Index ◽  
Treatment Comparison ◽  
Hip Abduction

Background: The anterior cruciate ligament (ACL) lesion causes a deficit in joint stability and mobility, trophism and muscular strength, generating asymmetries between the lower limbs. Objective: To verify the effect of a physiotherapeutic protocol on the Lower Limb Symmetry Index (LLSI) and the correlation between strength and EMGs, pre and post reconstruction of the ACL. Methods: Twenty subjects (10 ACLrg + 10 CONTg) were evaluated regarding isometric force and electrical activity of knee extensors, knee flexors and hip abductors. Results: A significant increase (P<0.01) in knee extension and flexion strength and hip abduction strength were observed both for the affected limb and non-affected limb. Regarding the LLSI, a significant increase was observed for knee extension and hip abduction movements in the pre- and post-treatment comparison, and between ACLrg X CONTg (P<0.01) for the knee extension movement in the pre-reconstruction phase of the ACL. A very strong correlation (r=0.945; P<0.01) was also observed between the LLSI strength X EMGs during knee extension, pre- and post-reconstruction surgery. Conclusions: Six months after reconstruction of the ACL, there was an increase in strength and EMG activity of the knee flexor, knee extensor and hip abductor muscles, leveling the LLSI between ACLrg and the CONTg, however, with a significant correlation between the two variables (strength X EMGs) for only one of the three movements (knee extension).

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.

scholarly journals The use of sulodexide in obliterating atherosclerosis of the lower extremities in patients with diabetes mellitus

1998 ◽  
Vol 44 (4) ◽  
pp. 16-18
Author(s):  
V. B. Bregovsky ◽  
A. G. Zalesskaya
Keyword(s):  
Lower Limb ◽  
Time Course ◽  
Clinical Manifestations ◽  
Activated Partial Thromboplastin Time ◽  
Lower Limbs ◽  
Allergic Reactions ◽  
Thrombin Time ◽  
Treadmill Test ◽  
Patients With Diabetes ◽  
Atherosclerosis Obliterans

Efficacy of sulodexin in diabetics with atherosclerosis obliterans of the lower limbs was assessed from changes in clinical manifestations of intermittent claudication, results of treadmill test, dopplerography of the lower limb vessels, lipidogram, and time course of coagulologic values. Twenty patients with involvement of the lower limb arteries with stages I I-1II according to Fontain were examined. After 10 intramuscular injections of Vessel Due F in a dose of 600 LRU, the drug was administered orally in a dose of 250 LRU twice a day for 12 weeks. Clinical improvement was attained in 88% of patients. The distance of painless walking increased from 152.7+22.2 to 283.6+52.4 m (by 86%), maximal distance from 221.2+29.5 to 376.6+56.9 m (by 70%). Study of changes in coagulologic values over the course of treatment showed increase of activated partial thromboplastin time from 30.7+2.7 to 38.4+1.5 sec (p<0.02), decrease of serum fibrinogen from 4.0+0.1 to 3.2+0.1 g/liter (p<0.003), and increase of thrombin time from 21.7+4.7 to 26.7+3.4 sec (p<0.006). Cholesterol decreased from 6.7+1.0 to 6.27+0.3 mmole/liter (p<.05) and triglycerides showed a tendency to decrease from 1.9+0.23 to 1.7+0.2 mmole/liter (NS). No allergic reactions or side effects were observed during therapy.

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