scholarly journals Active Passive Nature of Assistive Wearable Gait Augment Suit for Enhanced Mobility

2018 ◽  
Vol 30 (5) ◽  
pp. 717-728 ◽  
Author(s):  
Chetan Thakur ◽  
Kazunori Ogawa ◽  
Yuichi Kurita ◽  
◽  
◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activation ◽  
Feedforward Control ◽  
Surface Emg ◽  
Walking Gait ◽  
Lower Limb Muscles ◽  
Air Supply ◽  
Pilot Trials ◽  
Pneumatic Valves ◽  
Enhanced Mobility

In this paper we discuss the active and passive nature of the assistive wearable gait augment suit (AWGAS). AWGAS is a soft, wearable, lightweight, and assists walking gait by reducing muscle activation during walking. It augments walking by reducing the muscle activation of the posterior and anterior muscles of the lower limb. The suit uses pneumatic gel muscles (PGM), foot sensors for gait detection, and pneumatic valves to control the air pressure. The assistive force is provided using the motion in loop feedforward control loop using foot sensors in shoes. PGMs are actuated with the help of pneumatic valves and portable air tanks. The elastic nature of the PGM allows AWGAS to assist walking in the absence of the air supply which makes AWGAS both active and passive walking assist suit. To evaluate the active and passive nature of the AWGAS, we experimented to measure surface EMG (sEMG) of the lower limb muscles. sEMG was recorded for unassisted walking, i.e., without the suit, passive assisted walking, i.e., wearing the suit with no air supply and active assisted walking, i.e., wearing the suit with air supply set at 60 kPa. The results shows reduction in the muscle activity for both passive and active assisted walking as compared to unassisted walking. The pilot trials of the AWGAS were conducted in collaboration with local farmers in the Hiroshima prefecture in Japan where feedback received is complementing the results obtained during the experiments.

Analysis of Lower Extremity Muscle Activation Using EMG

2014 ◽  
Vol 573 ◽  
pp. 797-802
Author(s):  
L. Vidhya ◽  
S. Saranya ◽  
S. Poonguzhali
Keyword(s):  
Lower Limb ◽  
Muscle Activation ◽  
Surface Emg ◽  
Control Group ◽  
Therapy Planning ◽  
Activation Patterns ◽  
Gait Patterns ◽  
Lower Limb Muscles ◽  
Lower Extremity Muscle ◽  
Pathological Gait

Electromyography (EMG) has been widely used as a tool to understand and distinguish between normal and pathological gait. This study aims at understanding the activation patterns of lower limb muscles viz. Gastrocnemius and Tibialis Anterior in the dominant leg of subjects with normal (n=5) as well as pathological (n=2) gait patterns. The paper presents a normative pattern of these muscles during normal walking condition from which the deviation of affected group from the control group is observed. For this analysis, Surface EMG signals along with Force Sensitive Resistor values are acquired. These surface EMG signals picked up during the muscle activity are interfaced with a PC via EMG acquisition system. The acquired signals were processed and analyzed which can be used for rehabilitative therapy planning.

scholarly journals Human kinematic, kinetic and EMG data during different walking and stair ascending and descending tasks

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Tiziana Lencioni ◽  
Ilaria Carpinella ◽  
Marco Rabuffetti ◽  
Alberto Marzegan ◽  
Maurizio Ferrarin
Keyword(s):  
Lower Limb ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Simulation Models ◽  
Human Locomotion ◽  
Surface Emg ◽  
Whole Body ◽  
Bipedal Robots ◽  
Lower Limb Muscles ◽  
Reaction Forces

AbstractThis paper reports the kinematic, kinetic and electromyographic (EMG) dataset of human locomotion during level walking at different velocities, toe- and heel-walking, stairs ascending and descending. A sample of 50 healthy subjects, with an age between 6 and 72 years, is included. For each task, both raw data and computed variables are reported including: the 3D coordinates of external markers, the joint angles of lower limb in the sagittal, transversal and horizontal anatomical planes, the ground reaction forces and torques, the center of pressure, the lower limb joint mechanical moments and power, the displacement of the whole body center of mass, and the surface EMG signals of the main lower limb muscles. The data reported in the present study, acquired from subjects with different ages, represents a valuable dataset useful for future studies on locomotor function in humans, particularly as normative reference to analyze pathological gait, to test the performance of simulation models of bipedal locomotion, and to develop control algorithms for bipedal robots or active lower limb exoskeletons for rehabilitation.

scholarly journals Lower-limb muscle function is influenced by changing mechanical demands in cycling

2020 ◽  
pp. jeb.228221
Author(s):  
Adrian K. M. Lai ◽  
Taylor J. M. Dick ◽  
Nicholas A. T. Brown ◽  
Andrew A. Biewener ◽  
James M. Wakeling
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
Muscle Function ◽  
Muscle Activation ◽  
Functional Index ◽  
Lower Limb Muscles ◽  
Wide Range ◽  
Musculoskeletal Simulations ◽  
Contractile Performance

Although cycling is often considered a seemingly simple, reciprocal task, muscles must adapt their function to satisfy changes in mechanical demands induced by higher crank torques and faster pedalling cadences. We examined if muscle function was sensitive to these changes in mechanical demands across a wide range of pedalling conditions. We collected experimental data of cycling where crank torque and pedalling cadence were independently varied from 13-44 Nm and 60-140 RPM. These data were used in conjunction with musculoskeletal simulations and a recently developed functional index-based approach to characterise the role of the human lower-limb muscles. We found that in muscles that generate most of the mechanical power and work during cycling, greater crank torque induced shifts towards greater muscle activation, greater positive muscle-tendon unit (MTU) work and a more motor-like function, particularly in the limb extensors. Conversely, with faster pedalling cadence, the same muscles exhibited a phase advance in muscle activity prior to crank top dead centre, which led to greater negative MTU power and work and shifted the muscles to contract with more spring-like behaviour. Our results illustrate the capacity for muscles to adapt their function to satisfy the mechanical demands of the task, even during highly constrained reciprocal tasks such as cycling. Understanding how muscles shift their contractile performance under varied mechanical and environmental demands may inform decisions on how to optimise pedalling performance and to design targeted cycling rehabilitation therapies for muscle-specific injuries or deficits.

scholarly journals Comparative Study of Kinematics and Muscle Activity Between Elite and Amateur Table Tennis Players During Topspin Loop Against Backspin Movements

2018 ◽  
Vol 64 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Meizi Wang ◽  
Lin Fu ◽  
Yaodong Gu ◽  
Qichang Mei ◽  
Fengqin Fu ◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
Rectus Femoris ◽  
Surface Emg ◽  
Table Tennis ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Lower Limb Muscles ◽  
Balance Ability ◽  
Hip Flexion

Abstract This study investigated differences of lower limb kinematics and muscle activity during table tennis topspin loop against backspin movements between elite players (EPs) and amateur players (APs). Ten EPs and ten APs performed crosscourt backhand loop movements against the backspin ball with maximal power. Vicon motion analysis and a MEGA ME6000 system was used to capture kinematics and surface EMG data. The motion was divided into two phases, including the backswing and swing. The joints’ flexion and extension angle tendency between EPs and APs differed significantly. The coefficient of multiple correlation (CMC) values for EPs were all beyond 0.9, indicating high similarity of joint angles change. APs presented moderate similarity with CMC values from 0.5 to 0.75. Compared to APs, EPs presented larger ankle eversion, knee and hip flexion at the beginning moment of the backswing. In the sEMG test, EPs presented smaller standardized AEMG (average electromyography) of the lower limb muscles in the rectus femoris and tibia anterior on both sides. Additionally, the maximum activation of each muscle for EPs was smaller and MPF (mean power frequency) of the lower limb was greater during the whole movement. The present study revealed that EPs could complete this technical motion more economically than APs, meanwhile, EPs were more efficient in muscle usage and showed better balance ability.

Analysis of the activation modalities of the lower limb muscles during walking

2020 ◽  
Vol 28 (5) ◽  
pp. 521-532 ◽  
Author(s):  
Wei Li ◽  
Zhongli Li ◽  
Shuyan Qie ◽  
Huaqing Yang ◽  
Xuemei Chen ◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activation ◽  
Gait Cycle ◽  
Lower Limbs ◽  
Medial Gastrocnemius ◽  
Peak Time ◽  
Lower Limb Muscles ◽  
Emg Signal ◽  
Limb Muscles ◽  
Activation Intervals

BACKGROUND: Walking is a basic human activity and many orthopedic diseases can manifest with gait abnormalities. However, the muscle activation intervals of lower limbs are not clear. OBJECTIVE: The aim of this study was to explore the contraction patterns of lower limb muscles by analyzing activation intervals using surface electromyography (SEMG) during walking. METHODS: Four muscles including the tibialis anterior (TA), lateral gastrocnemius (LG), medial gastrocnemius (MG), and rectus femoris (RF) of bilateral lower extremity of 92 healthy subjects were selected for SEMG measurements. The number of activations (activation intervals) and the point of the highest root mean square (RMS) EMG signal in the percentage of the gait cycle (GC) were used to analyze muscle activities. RESULTS: The majority of TA and RF showed two activation intervals and both gastrocnemius parts three activation intervals during walking. The point of the highest RMS EMG signal in the percentage of the GC for TA, LG, MG and RF are 5%, 41%, 40%, and 8%, respectively. The activation intervals were mostly affected by age, height, different genders and bilateral limbs. CONCLUSION: This study identified the different activation intervals (four for each muscle) and the proportion of healthy adults in which they occurred during the normal gait cycle. These different activation intervals provided a new insight to evaluate the function of nerves and muscles. In addition, the activation interval and RMS peak time proposed in this study can be used as new parameters for gait analysis.

scholarly journals Fibre operating lengths of human lower limb muscles during walking

2011 ◽  
Vol 366 (1570) ◽  
pp. 1530-1539 ◽  
Author(s):  
Edith M. Arnold ◽  
Scott L. Delp
Keyword(s):  
Muscle Fibre ◽  
Lower Limb ◽  
Muscle Activation ◽  
Fibre Length ◽  
Musculoskeletal Model ◽  
Muscle Fibres ◽  
Joint Angles ◽  
Moment Arms ◽  
Lower Limb Muscles ◽  
Limb Muscles

Muscles actuate movement by generating forces. The forces generated by muscles are highly dependent on their fibre lengths, yet it is difficult to measure the lengths over which muscle fibres operate during movement. We combined experimental measurements of joint angles and muscle activation patterns during walking with a musculoskeletal model that captures the relationships between muscle fibre lengths, joint angles and muscle activations for muscles of the lower limb. We used this musculoskeletal model to produce a simulation of muscle–tendon dynamics during walking and calculated fibre operating lengths (i.e. the length of muscle fibres relative to their optimal fibre length) for 17 lower limb muscles. Our results indicate that when musculotendon compliance is low, the muscle fibre operating length is determined predominantly by the joint angles and muscle moment arms. If musculotendon compliance is high, muscle fibre operating length is more dependent on activation level and force–length–velocity effects. We found that muscles operate on multiple limbs of the force–length curve (i.e. ascending, plateau and descending limbs) during the gait cycle, but are active within a smaller portion of their total operating range.

scholarly journals Investigation of Lower Limb Fatigue on Two Standing Posture

2016 ◽  
Vol 11 (1) ◽  
pp. 208 ◽  
Author(s):  
Sari Julia Sartika ◽  
Siti Zawiah Dawal
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Lower Limb ◽  
Muscle Activity ◽  
Surface Emg ◽  
Sorting Task ◽  
Low Back ◽  
Standing Posture ◽  
Prolonged Standing ◽  
Lower Limb Muscles

The purpose of this study was to investigate the different effect from the two standing posture on lower limb fatigue and discomfort. Sixteen subjects (eight females and eight males), aged between 23-29 years, participated in the experiment. They performed a sorting task in front of a grading table by picking and placing objects for 90 minutes in two posture (1) standing and (2) standing using a footrest. Muscle activity was recorded with surface EMG through disposable electrodes. The result shows that standing for ninety minutes developed fatigue in lower limb muscles and back muscles that lead to low back pain. Standing using a footrest result proper posture for prolonged standing period and reduce force at the back. It also results less fatigue and reduce the %MVC of EMG. So, it is recommended to attach a footrest in standing workstation to reduce the fatigue and discomfort.Keywords:fatigue, posture, standing,lower limb, EMG

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