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Hamid Reza Khalkhali - One of the best experts on this subject based on the ideXlab platform.
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Influence of unstable footwear on Lower Leg Muscle activity, volume change and subjective discomfort during prolonged standing.
Applied Ergonomics, 2016Co-Authors: Zanyar Karimi, Teimour Allahyari, Mahmood Reza Azghani, Hamid Reza KhalkhaliAbstract:Abstract Purpose The present study was an attempt to investigate the effect of unstable footwear on Lower Leg Muscle activity, volume change and subjective discomfort during prolonged standing. Methods Ten healthy subjects were recruited to stand for 2 h in three footwear conditions: barefoot, flat-bottomed shoe and unstable shoe. During standing, Lower Leg discomfort and EMG activity of medial gastrocnemius (MG) and tibialis anterior (TA) Muscles were continuously monitored. Changes in Lower Leg volume over standing time also were measured. Results Lower Leg discomfort rating reduced significantly while subjects standing on unstable shoe compared to the flat-bottomed shoe and barefoot condition. For Lower Leg volume, less changes also were observed with unstable shoe. The activity level and variation of right MG Muscle was greater with unstable shoe compared to the other footwear conditions; however regarding the left MG Muscle, significant difference was found between unstable shoe and flat-bottomed shoe only for activity level. Furthermore no significant differences were observed for the activity level and variation of TA Muscles (right/left) among all footwear conditions. Conclusions The findings suggested that prolonged standing with unstable footwear produces changes in Lower Leg Muscles activity and leads to less volume changes. Perceived discomfort also was Lower for this type of footwear and this might mean that unstable footwear can be used as ergonomic solution for employees whose work requires prolonged standing.
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Influence of unstable footwear on Lower Leg Muscle activity, volume change and subjective discomfort during prolonged standing.
Applied ergonomics, 2015Co-Authors: Zanyar Karimi, Teimour Allahyari, Mahmood Reza Azghani, Hamid Reza KhalkhaliAbstract:The present study was an attempt to investigate the effect of unstable footwear on Lower Leg Muscle activity, volume change and subjective discomfort during prolonged standing. Ten healthy subjects were recruited to stand for 2 h in three footwear conditions: barefoot, flat-bottomed shoe and unstable shoe. During standing, Lower Leg discomfort and EMG activity of medial gastrocnemius (MG) and tibialis anterior (TA) Muscles were continuously monitored. Changes in Lower Leg volume over standing time also were measured. Lower Leg discomfort rating reduced significantly while subjects standing on unstable shoe compared to the flat-bottomed shoe and barefoot condition. For Lower Leg volume, less changes also were observed with unstable shoe. The activity level and variation of right MG Muscle was greater with unstable shoe compared to the other footwear conditions; however regarding the left MG Muscle, significant difference was found between unstable shoe and flat-bottomed shoe only for activity level. Furthermore no significant differences were observed for the activity level and variation of TA Muscles (right/left) among all footwear conditions. The findings suggested that prolonged standing with unstable footwear produces changes in Lower Leg Muscles activity and leads to less volume changes. Perceived discomfort also was Lower for this type of footwear and this might mean that unstable footwear can be used as ergonomic solution for employees whose work requires prolonged standing. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.
Zanyar Karimi - One of the best experts on this subject based on the ideXlab platform.
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Influence of unstable footwear on Lower Leg Muscle activity, volume change and subjective discomfort during prolonged standing.
Applied Ergonomics, 2016Co-Authors: Zanyar Karimi, Teimour Allahyari, Mahmood Reza Azghani, Hamid Reza KhalkhaliAbstract:Abstract Purpose The present study was an attempt to investigate the effect of unstable footwear on Lower Leg Muscle activity, volume change and subjective discomfort during prolonged standing. Methods Ten healthy subjects were recruited to stand for 2 h in three footwear conditions: barefoot, flat-bottomed shoe and unstable shoe. During standing, Lower Leg discomfort and EMG activity of medial gastrocnemius (MG) and tibialis anterior (TA) Muscles were continuously monitored. Changes in Lower Leg volume over standing time also were measured. Results Lower Leg discomfort rating reduced significantly while subjects standing on unstable shoe compared to the flat-bottomed shoe and barefoot condition. For Lower Leg volume, less changes also were observed with unstable shoe. The activity level and variation of right MG Muscle was greater with unstable shoe compared to the other footwear conditions; however regarding the left MG Muscle, significant difference was found between unstable shoe and flat-bottomed shoe only for activity level. Furthermore no significant differences were observed for the activity level and variation of TA Muscles (right/left) among all footwear conditions. Conclusions The findings suggested that prolonged standing with unstable footwear produces changes in Lower Leg Muscles activity and leads to less volume changes. Perceived discomfort also was Lower for this type of footwear and this might mean that unstable footwear can be used as ergonomic solution for employees whose work requires prolonged standing.
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Influence of unstable footwear on Lower Leg Muscle activity, volume change and subjective discomfort during prolonged standing.
Applied ergonomics, 2015Co-Authors: Zanyar Karimi, Teimour Allahyari, Mahmood Reza Azghani, Hamid Reza KhalkhaliAbstract:The present study was an attempt to investigate the effect of unstable footwear on Lower Leg Muscle activity, volume change and subjective discomfort during prolonged standing. Ten healthy subjects were recruited to stand for 2 h in three footwear conditions: barefoot, flat-bottomed shoe and unstable shoe. During standing, Lower Leg discomfort and EMG activity of medial gastrocnemius (MG) and tibialis anterior (TA) Muscles were continuously monitored. Changes in Lower Leg volume over standing time also were measured. Lower Leg discomfort rating reduced significantly while subjects standing on unstable shoe compared to the flat-bottomed shoe and barefoot condition. For Lower Leg volume, less changes also were observed with unstable shoe. The activity level and variation of right MG Muscle was greater with unstable shoe compared to the other footwear conditions; however regarding the left MG Muscle, significant difference was found between unstable shoe and flat-bottomed shoe only for activity level. Furthermore no significant differences were observed for the activity level and variation of TA Muscles (right/left) among all footwear conditions. The findings suggested that prolonged standing with unstable footwear produces changes in Lower Leg Muscles activity and leads to less volume changes. Perceived discomfort also was Lower for this type of footwear and this might mean that unstable footwear can be used as ergonomic solution for employees whose work requires prolonged standing. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.
Alexander Badrisprowitz - One of the best experts on this subject based on the ideXlab platform.
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series elastic behavior of biarticular Muscle tendon structure in a robotic Leg
Frontiers in Neurorobotics, 2019Co-Authors: Felix Ruppert, Alexander BadrisprowitzAbstract:We investigate the role of Lower Leg Muscle-tendon structures in providing serial elastic behavior to the hip actuator. We present a Leg design with physical elastic elements in Leg angle and virtual Leg axis direction, and its impact onto energy efficient Legged locomotion. By testing and comparing two robotic Lower Leg spring configurations, we can provide potential explanations of the functionality of similar animal Leg morphologies with Lower Leg Muscle-tendon network structures. We investigate the effects of Leg angle compliance during locomotion. In a proof of concept, we show that a Leg with a gastrocnemius inspired elasticity possesses elastic components that deflect in Leg angle directions. The Leg design with elastic elements in Leg angle direction can store hip actuator energy in the series elastic element. We then show the Leg’s advantages in mechanical design in a vertical drop experiment. In the drop experiments the biarticular Leg requires 46% less power. During drop loading, the Leg adapts its posture and stores the energy in its springs. The increased energy storing capacity in Leg angle direction reduces energy requirements and cost of transport by 31% during dynamic hopping to a cost of transport of 1.2 at 0.9 kg body weight. The biarticular robot Leg design has major advantages, especially compared to more traditional robot designs. Despite its high degree of under-actuation, it is easy to converge into and maintain dynamic hopping locomotion. The presented control is based on a simple-to-implement, feed- forward pattern generator. The biartiuclar Legs lightweight design can be rapidly assembled and is largely made from elements created by rapid prototyping. At the same time it is robust, and passively withstands drops from 200% body height. The biarticular Leg shows, to the best of the authors’ knowledge, the lowest achieved relative cost of transport documented for all dynamically hopping and running robots of 64% Lower than a comparable natural runner.
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series elastic behavior of biarticular Muscle tendon structure in a robotic Leg
Frontiers in Neurorobotics, 2019Co-Authors: Felix Ruppert, Alexander BadrisprowitzAbstract:We investigate the role of Lower Leg Muscle-tendon structures in providing serial elastic behavior to the hip actuator. We present a Leg design with physical elastic elements in Leg angle and virtual Leg axis direction, and its impact onto energy efficient Legged locomotion. By testing and comparing two robotic Lower Leg spring configurations, we can provide potential explanations of the functionality of similar animal Leg morphologies with Lower Leg Muscle-tendon network structures. We investigate the effects of Leg angle compliance during locomotion. In a proof of concept, we show that a Leg with a gastrocnemius inspired elasticity possesses elastic components that deflect in Leg angle directions. The Leg design with elastic elements in Leg angle direction can store hip actuator energy in the series elastic element. We then show the Leg's advantages in mechanical design in a vertical drop experiment. In the drop experiments the biarticular Leg requires 46% less power. During drop loading, the Leg adapts its posture and stores the energy in its springs. The increased energy storing capacity in Leg angle direction reduces energy requirements and cost of transport by 31% during dynamic hopping to a cost of transport of 1.2 at 0.9 kg body weight. The biarticular robot Leg design has major advantages, especially compared to more traditional robot designs. Despite its high degree of under-actuation, it is easy to converge into and maintain dynamic hopping locomotion. The presented control is based on a simple-to-implement, feed-forward pattern generator. The biarticular Legs lightweight design can be rapidly assembled and is largely made from elements created by rapid prototyping. At the same time it is robust, and passively withstands drops from 200% body height. The biarticular Leg shows, to the best of the authors' knowledge, the lowest achieved relative cost of transport documented for all dynamically hopping and running robots of 64% of a comparable natural runner's COT.
József Tihanyi - One of the best experts on this subject based on the ideXlab platform.
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Lower Leg Muscle-tendon unit characteristics are related to marathon running performance.
Scientific reports, 2020Co-Authors: Bálint Barna H Kovács, István Kóbor, Zsolt Gyimes, Örs Sebestyén, József TihanyiAbstract:The human ankle joint and plantar flexor Muscle-tendon unit play an important role in endurance running. It has been assumed that Muscle and tendon interactions and their biomechanical behaviours depend on their morphological and architectural characteristics. We aimed to study how plantar flexor Muscle characteristics influence marathon running performance and to determine whether there is any difference in the role of the soleus and gastrocnemii. The right Lower Leg of ten male distance runners was scanned with magnetic resonance imagining. The cross-sectional areas of the Achilles tendon, soleus, and lateral and medial gastrocnemius were measured, and the Muscle volumes were calculated. Additional ultrasound scanning was used to estimate the fascicle length of each Muscle to calculate the physiological cross-sectional area. Correlations were found between marathon running performance and soleus volume (r = 0.55, p = 0.048), soleus cross-sectional area (r = 0.57, p = 0.04), soleus physiological cross-sectional area (PCSA-IAAF r = 0.77, p < 0.01, CI± 0.28 to 0.94), Achilles tendon thickness (r = 0.65, p < 0.01), and soleus Muscle-to-tendon ratio (r = 0.68, p = 0.03). None of the gastrocnemius characteristics were associated with marathon performance. We concluded that a larger soleus Muscle with a thicker Achilles tendon is associated with better marathon performance. Based on these results, it can be concluded the morphological characteristics of the Lower Leg Muscle-tendon unit correlate with running performance.
F Hlavacka - One of the best experts on this subject based on the ideXlab platform.
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parkinson s disease versus ageing different postural responses to soleus Muscle vibration
Gait & Posture, 2018Co-Authors: D Bzduskova, Peter Valkovic, Zuzana Hirjakova, J Kimijanova, F HlavackaAbstract:Abstract Background Impairments of postural stability occur with increasing age and in neurodegenerative diseases like the Parkinson's disease (PD). While changes in balance have been described in many studies under steady-state conditions, less is known about the dynamic changes in balance following sudden transition to different sensory inputs. Research question The aim was to clarify different effects of age and Parkinson's disease on dynamic postural responses immediately after Lower Leg Muscle stimulation offset. Sudden removing of active sensory input represents a transient period in balance control. Methods Postural responses of 13 young, 13 healthy elderly and 13 PD patients to proprioceptive bilateral vibration of soleus Muscles during stance were assessed by a force platform and two accelerometers attached on the upper and the Lower trunk. The experimental protocol consisted of 2 conditions of soleus Muscle vibration with 1) eyes open and 2) eyes closed randomly repeated four times. Results During vibration period before stimulus offset, postural responses were similar in elderly and PD patients. Contrary, immediately after vibration offset significantly larger backward amplitude of centre of foot pressure (CoP) displacement and trunk tilts were observed in PD patients compared to healthy peers. In returning to vertical position, peak-to-peak amplitudes, maximal velocity of CoP and trunk tilts significantly increased in PD patients. Without vision, their postural responses were more enhanced. The differences between young and elderly were found in most parameters in transient period after vibration offset and also during vibration. Significance The PD patients showed more unstable transient postural responses to selective sensory stimulation switch off, which may reflect impairment of sensory reweighting in balance control. Understanding how early stages PD patients differ in balance control from neurologically intact peers may help researchers and clinicians to refine their intervention and fall prevention programs.
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human postural response to Lower Leg Muscle vibration of different duration
Physiological Research, 2006Co-Authors: N Capicikova, Laura Rocchi, F Hlavacka, Lorenzo Chiari, Angelo CappelloAbstract:Summary Body lean response to bilateral vibrations of soleus Muscles were investigated in order to understand the influence of proprioceptive input from Lower Leg in human stance control. Proprioceptive stimulation was applied to 17 healthy subjects by two vibrators placed on the soleus Muscles. Frequency and amplitude of vibration were 60 Hz and 1 mm, respectively. Vibration was applied after a 30 s of baseline. The vibration duration of 10, 20, 30 s respectively was used with following 30 s rest. Subjects stood on the force platform with eyes closed. Postural responses were characterized by center of pressure (CoP) displacements in the anterior-posterior (AP) direction. The CoP-AP shifts as well as their amplitudes and velocities were analyzed before, during and after vibration. Vibration of soleus Muscles gradually increased backward body tilts. There was a clear dependence of the magnitude of final CoP shift on the duration of vibration. The amplitude and velocity of body sway increased during vibration and amplitude was significantly modulated by duration of vibration as well. Comparison of amplitude and velocity of body sway before and after vibration showed significant post-effects. Presented findings showed that somatosensory stimulation has a long-term, direction-specific influence on the control of postural orientation during stance. Further, the proprioceptive input altered by soleus Muscles vibration showed significant changes in postural equilibrium during period of vibration with interesting post-effects also.
