scholarly journals A Novel Lightweight Wearable Soft Exosuit for Reducing the Metabolic Rate and Muscle Fatigue

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 215
Author(s):  
Lingxing Chen ◽  
Chunjie Chen ◽  
Zhuo Wang ◽  
Xin Ye ◽  
Yida Liu ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
The Novel ◽  
Robotic Devices ◽  
Extra Weight ◽  
Hip Flexion ◽  
Rehabilitation Exercises ◽  
Hip Extension ◽  
Soft Exosuit

Wearable robotic devices have been proved to considerably reduce the energy expenditure of human walking. It is not only suitable for healthy people, but also for some patients who require rehabilitation exercises. However, in many cases, the weight of soft exosuits are relatively large, which makes it difficult for the assistant effect of the system to offset the metabolic consumption caused by the extra weight, and the heavy weight will make people uncomfortable. Therefore, reducing the weight of the whole system as much as possible and keeping the soft exosuit output power unchanged, may improve the comfort of users and further reduce the metabolic consumption. In this paper, we show that a novel lightweight soft exosuit which is currently the lightest among all known powered exoskeletons, which assists hip flexion. Indicated from the result of experiment, the novel lightweight soft exosuit reduces the metabolic consumption rate of wearers when walking on the treadmill at 5 km per hour by 11.52% compared with locomotion without the exosuit. Additionally, it can reduce more metabolic consumption than the hip extension assisted (HEA) and hip flexion assisted (HFA) soft exosuit which our team designed previously, which has a large weight. The muscle fatigue experiments show that using the lightweight soft exosuit can also reduce muscle fatigue by about 10.7%, 40.5% and 5.9% for rectus femoris, vastus lateralis and gastrocnemius respectively compared with locomotion without the exosuit. It is demonstrated that decreasing the weight of soft exosuit while maintaining the output almost unchanged can further reduce metabolic consumption and muscle fatigue, and appropriately improve the users’ comfort.

scholarly journals Implementation of a Portable Electromyographic Prototype for the Detection of Muscle Fatigue

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 619 ◽  
Author(s):  
Sandra De la Peña ◽  
Aura Polo ◽  
Carlos Robles-Algarín
Keyword(s):  
Muscle Fatigue ◽  
Muscular Strength ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Skin Surface ◽  
Mean Frequency ◽  
Signal Characteristics ◽  
Dynamic Contractions ◽  
Experienced Fatigue ◽  
Two Parameters

Surface electromyography (sEMG) applied to the sports training area makes possible the observation of fatigue as well as the generation of muscular strength, through the study of changes in signal characteristics, such as peak-to-peak amplitude, mean frequency and median, among others. In this sense, this work presents the design of a portable prototype for the acquisition and processing of electromyographic (EMG) signals aimed at the detection of muscle fatigue in athletes. Using two Bluetooth Bee modules, a wireless communication was performed in order to send the muscular electrical activity of the skin surface to a user interface developed in LabVIEW. A group of players from the Volleyball team of the Universidad del Magdalena, performed a series of exercise routines with dynamic contractions and as they experienced fatigue, samples were taken of the contractions made. The tests were performed on the vastus lateralis and rectus femoris muscles. The analysis of fatigue under dynamic conditions of the two parameters studied, in frequency and time, showed that it is more pertinent to estimate fatigue indices in the frequency domain.

The frequency of alternate muscle activity is associated with the attenuation in muscle fatigue

2006 ◽  
Vol 101 (3) ◽  
pp. 715-720 ◽  
Author(s):  
Motoki Kouzaki ◽  
Minoru Shinohara
Keyword(s):  
Muscle Fatigue ◽  
Muscle Activity ◽  
Healthy Subjects ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Sustained Contraction ◽  
Low Level ◽  
Before And After

Alternate muscle activity between synergist muscles has been demonstrated during low-level sustained contractions [≤5% of maximal voluntary contraction (MVC) force]. To determine the functional significance of the alternate muscle activity, the association between the frequency of alternate muscle activity during a low-level sustained knee extension and the reduction in knee extension MVC force was studied. Forty-one healthy subjects performed a sustained knee extension at 2.5% MVC force for 1 h. Before and after the sustained knee extension, MVC force was measured. The surface electromyogram was recorded from the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) muscles. The frequency of alternate muscle activity for RF-VL, RF-VM, and VL-VM pairs was determined during the sustained contraction. The frequency of alternate muscle activity ranged from 4 to 11 times/h for RF-VL (7.0 ± 2.0 times/h) and RF-VM (7.0 ± 1.9 times/h) pairs, but it was only 0 to 2 times/h for the VL-VM pair (0.5 ± 0.7 times/h). MVC force after the sustained contraction decreased by 14% ( P < 0.01) from 573.6 ± 145.2 N to 483.3 ± 130.5 N. The amount of reduction in MVC force was negatively correlated with the frequency of alternate muscle activity for the RF-VL and RF-VM pairs ( P < 0.001 and r = 0.65 for both) but not for the VL-VM pair. The results demonstrate that subjects with more frequent alternate muscle activity experience less muscle fatigue. We conclude that the alternate muscle activity between synergist muscles attenuates muscle fatigue.

scholarly journals A Time Division Multiplexing Inspired Lightweight Soft Exoskeleton for Hip and Ankle Joint Assistance

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1150
Author(s):  
Xin Ye ◽  
Chunjie Chen ◽  
Yanguo Shi ◽  
Lingxing Chen ◽  
Zhuo Wang ◽  
...  
Keyword(s):  
Gait Cycle ◽  
Vastus Lateralis ◽  
Plantar Flexion ◽  
Rectus Femoris ◽  
Loading Path ◽  
Time Division Multiplexing ◽  
Natural Motion ◽  
Actuation Scheme ◽  
Hip Flexion ◽  
Time Division

Exoskeleton robots are frequently applied to augment or assist the user’s natural motion. Generally, each assisted joint corresponds to at least one specific motor to ensure the independence of movement between joints. This means that as there are more joints to be assisted, more motors are required, resulting in increasing robot weight, decreasing motor utilization, and weakening exoskeleton robot assistance efficiency. To solve this problem, the design and control of a lightweight soft exoskeleton that assists hip-plantar flexion of both legs in different phases during a gait cycle with only one motor is presented in this paper. Inspired by time-division multiplexing and the symmetry of walking motion, an actuation scheme that uses different time-periods of the same motor to transfer different forces to different joints is formulated. An automatic winding device is designed to dynamically change the loading path of the assistive force at different phases of the gait cycle. The system is designed to assist hip flexion and plantar flexion of both legs with only one motor, since there is no overlap between the hip flexion movement and the toe-offs movement of the separate legs during walking. The weight of the whole system is only 2.24 kg. PD iterative control is accomplished by an algorithm that utilizes IMUs attached on the thigh recognizing the maximum hip extension angle to characterize toe-offs indirectly, and two load cells to monitor the cable tension. In the study of six subjects, muscle fatigue of the rectus femoris, vastus lateralis, gastrocnemius and soleus decreased by an average of 14.69%, 6.66%, 17.71%, and 8.15%, respectively, compared to scenarios without an exoskeleton.

scholarly journals Acute effects of anterior thigh foam rolling on hip angle, knee angle, and rectus femoris length in the modified Thomas test

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1281 ◽  
Author(s):  
Andrew D. Vigotsky ◽  
Gregory J. Lehman ◽  
Bret Contreras ◽  
Chris Beardsley ◽  
Bryan Chung ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Rectus Femoris ◽  
Length Change ◽  
Acute Effects ◽  
Foam Rolling ◽  
Anterior Thigh ◽  
Before And After ◽  
Small Change ◽  
Hip Flexion ◽  
Hip Extension

Background.Foam rolling has been shown to acutely increase range of motion (ROM) during knee flexion and hip flexion with the experimenter applying an external force, yet no study to date has measured hip extensibility as a result of foam rolling with controlled knee flexion and hip extension moments. The purpose of this study was to investigate the acute effects of foam rolling on hip extension, knee flexion, and rectus femoris length during the modified Thomas test.Methods.Twenty-three healthy participants (male = 7; female = 16; age = 22 ± 3.3 years; height = 170 ± 9.18 cm; mass = 67.7 ± 14.9 kg) performed two, one-minute bouts of foam rolling applied to the anterior thigh. Hip extension and knee flexion were measured via motion capture before and after the foam rolling intervention, from which rectus femoris length was calculated.Results.Although the increase in hip extension (change = +1.86° (+0.11, +3.61); z(22) = 2.08;p= 0.0372; Pearson’sr= 0.43 (0.02, 0.72)) was not due to chance alone, it cannot be said that the observed changes in knee flexion (change = −1.39° (−5.53, +2.75); t(22) = −0.70;p= 0.4933; Cohen’sd= − 0.15 (−0.58, 0.29)) or rectus femoris length (change = −0.005 (−0.013, +0.003); t(22) = −1.30;p= 0.2070; Cohen’sd= − 0.27 (−0.70, 0.16)) were not due to chance alone.Conclusions.Although a small change in hip extension was observed, no changes in knee flexion or rectus femoris length were observed. From these data, it appears unlikely that foam rolling applied to the anterior thigh will improve passive hip extension and knee flexion ROM, especially if performed in combination with a dynamic stretching protocol.

scholarly journals Modelling of Muscle Force Distributions During Barefoot and Shod Running

2015 ◽  
Vol 47 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Jonathan Sinclair ◽  
Stephen Atkins ◽  
Jim Richards ◽  
Hayley Vincent
Keyword(s):  
Repeated Measures ◽  
Sagittal Plane ◽  
Vastus Lateralis ◽  
Reaction Force ◽  
Rectus Femoris ◽  
Camera Motion ◽  
Barefoot Running ◽  
Chronic Injuries ◽  
Analysis System ◽  
Hip Flexion

Abstract Research interest in barefoot running has expanded considerably in recent years, based around the notion that running without shoes is associated with a reduced incidence of chronic injuries. The aim of the current investigation was to examine the differences in the forces produced by different skeletal muscles during barefoot and shod running. Fifteen male participants ran at 4.0 m·s-1 (± 5%). Kinematics were measured using an eight camera motion analysis system alongside ground reaction force parameters. Differences in sagittal plane kinematics and muscle forces between footwear conditions were examined using repeated measures or Freidman’s ANOVA. The kinematic analysis showed that the shod condition was associated with significantly more hip flexion, whilst barefoot running was linked with significantly more flexion at the knee and plantarflexion at the ankle. The examination of muscle kinetics indicated that peak forces from Rectus femoris, Vastus medialis, Vastus lateralis, Tibialis anterior were significantly larger in the shod condition whereas Gastrocnemius forces were significantly larger during barefoot running. These observations provide further insight into the mechanical alterations that runners make when running without shoes. Such findings may also deliver important information to runners regarding their susceptibility to chronic injuries in different footwear conditions.

scholarly journals Comparison of Lower Extremity Kinematics and Hip Muscle Activation During Rehabilitation Tasks Between Sexes

2010 ◽  
Vol 45 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Maureen K. Dwyer ◽  
Samantha N. Boudreau ◽  
Carl G. Mattacola ◽  
Timothy L. Uhl ◽  
Christian Lattermann
Keyword(s):  
Sex Differences ◽  
Lower Extremity ◽  
Knee Flexion ◽  
Muscle Activation ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Kinetic Chain ◽  
Closed Kinetic Chain ◽  
Hip Flexion ◽  
Rehabilitation Exercises

Abstract Context: Closed kinetic chain exercises are an integral part of rehabilitation programs after lower extremity injury. Sex differences in lower extremity kinematics have been reported during landing and cutting; however, less is known about sex differences in movement patterns and activation of the hip musculature during common lower extremity rehabilitation exercises. Objective: To determine whether lower extremity kinematics and muscle activation levels differ between sexes during closed kinetic chain rehabilitation exercises. Design: Cross-sectional with 1 between-subjects factor (sex) and 1 within-subjects factor (exercise). Setting: Research laboratory. Patients or Other Participants: Participants included 21 women (age  =  23 ± 5.8 years, height  =  167.6 ± 5.1 cm, mass  =  63.7 ± 5.9 kg) and 21 men (age  =  23 ± 4.0 years, height  =  181.4 ± 7.4 cm, mass  =  85.6 ± 16.5 kg). Intervention(s): In 1 testing session, participants performed 3 trials each of single-leg squat, lunge, and step-up-and-over exercises. Main Outcome Measure(s): We recorded the peak joint angles (degrees) of knee flexion and valgus and hip flexion, extension, adduction, and external rotation for each exercise. We also recorded the electromyographic activity of the gluteus maximus, rectus femoris, adductor longus, and bilateral gluteus medius muscles for the concentric and eccentric phases of each exercise. Results: Peak knee flexion angles were smaller and peak hip extension angles were larger for women than for men across all tasks. Peak hip flexion angles during the single-leg squat were smaller for women than for men. Mean root-mean-square amplitudes for the gluteus maximus and rectus femoris muscles in both the concentric and eccentric phases of the 3 exercises were greater for women than for men. Conclusions: Sex differences were observed in sagittal-plane movement patterns during the rehabilitation exercises. Because of the sex differences observed in our study, future researchers need to compare the findings for injured participants by sex to garner a better representation of altered kinematic angles and muscle activation levels due to injury.

scholarly journals A Semi-active Exoskeleton Based on EMGs Reduces Muscle Fatigue When Squatting

2021 ◽  
Vol 15 ◽  
Author(s):  
Zhuo Wang ◽  
Xinyu Wu ◽  
Yu Zhang ◽  
Chunjie Chen ◽  
Shoubin Liu ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Metabolic Cost ◽  
Rectus Femoris ◽  
Elastic Support ◽  
Erector Spinae ◽  
Rigid Support ◽  
Working Environments ◽  
Vastus Intermedius

In dynamic manufacturing and warehousing environments, the work scene made it impossible for workers to sit, so workers suffer from muscle fatigue of the lower limb caused by standing or squatting for a long period of time. In this paper, a semi-active exoskeleton used to reduce the muscle fatigue of the lower limb was designed and evaluated. (i) Background: The advantages and disadvantages of assistive exoskeletons developed for industrial purposes were introduced. (ii) Simulation: The process of squatting was simulated in the AnyBody.7.1 software, the result showed that muscle activity of the gluteus maximus, rectus femoris, vastus medialis, vastus lateralis, vastus intermedius, and erector spinae increased with increasing of knee flexion angle. (iii) Design: The exoskeleton was designed with three working modes: rigid-support mode, elastic-support mode and follow mode. Rigid-support mode was suitable for scenes where the squatting posture is stable, while elastic-support mode was beneficial for working environments where the height of squatting varied frequently.The working environments were identified intelligently based on the EMGs of the gluteus maximus, and quadriceps, and the motor was controlled to switch the working mode between rigid-support mode and elastic-support mode. In follow mode, the exoskeleton moves freely with users without interfering with activities such as walking, ascending and descending stairs. (iv) Experiments: Three sets of experiments were conducted to evaluate the effect of exoskeleton. Experiment one was conducted to measure the surface electromyography signal (EMGs) in both condition of with and without exoskeleton, the root mean square of EMGs amplitude of soleus, vastus lateralis, vastus medialis, gastrocnemius, vastus intermedius, rectus femoris, gluteus maximus, and erector spinae were reduced by 98.5, 97.89, 80.09, 77.27, 96.73, 94.17, 70.71, and 36.32%, respectively, with the assistance of the exoskeleton. The purpose of experiment two was aimed to measure the plantar pressure with and without exoskeleton. With exoskeleton, the percentage of weight through subject's feet was reduced by 63.94, 64.52, and 65.61% respectively at 60°, 90°, and 120° of knee flexion angle, compared to the condition of without exoskeleton. Experiment three was purposed to measure the metabolic cost at a speed of 4 and 5 km/h with and without exoskeleton. Experiment results showed that the average additional metabolic cost introduced by exoskeleton was 2.525 and 2.85%. It indicated that the exoskeleton would not interfere with the movement of the wearer Seriously in follow mode. (v) Conclusion: The exoskeleton not only effectively reduced muscle fatigue, but also avoided interfering with the free movement of the wearer.

Form Switching During Human Locomotion: Traversing Wedges in a Single Step

2000 ◽  
Vol 84 (2) ◽  
pp. 605-615 ◽  
Author(s):  
Gammon M. Earhart ◽  
Amy J. Bastian
Keyword(s):  
Neural Control ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Single Step ◽  
Level Surface ◽  
Heel Strike ◽  
Joint Angles ◽  
Hip Flexion ◽  
Anterior Tibialis

We examined the neural control strategies used to accommodate discrete alterations in walking surface inclination. Normal subjects were tested walking on a level surface and on different wedges (10°, 15°, 20°, and 30°) presented in the context of level walking. On a given trial, a subject walked on a level surface in approach to a wedge, took a single step on the wedge, and continued walking on an elevated level surface beyond the wedge. As wedge inclination increased, subjects linearly increased peak joint angles. Changes in timing of peak joint angles and electromyograms were not linear. Subjects used two distinct temporal strategies, or forms, to traverse the wedges. One form was used for walking on a level surface and on the 10° wedge, another form for walking on the 20° and 30° wedges. In the level/10° form, peak hip flexion occurred well before heel strike (HS) and peak dorsiflexion occurred in late stance. In the 20°/30° form, peak hip flexion was delayed by 12% of the stride cycle and peak dorsiflexion was reached 12% earlier. For the level/10° form, onsets of the rectus femoris, gluteus maximus, and vastus lateralis muscles were well before HS and offset of the anterior tibialis was at HS. For the 20°/30° form, onsets of the rectus femoris, gluteus maximus, and vastus lateralis and offset of the anterior tibialis were all delayed by 12% of the stride cycle. Muscles shifted as a group, rather than individually, between the forms. Subjects traversing a 15° wedge switched back and forth between the two forms in consecutive trials, suggesting the presence of a transition zone. Differences between the forms can be explained by the differing biomechanical constraints imposed by the wedges. Steeper wedges necessitate changes in limb orientation to accommodate the surface, altering limb orientation with respect to gravity and making it necessary to pull the body forward over the foot. The use of different forms of behavior is a common theme in neural control and represents an efficient means of coordinating and adapting movement to meet changing environmental demands. The forms of locomotion reported here are likely used on a regular basis in real-world settings.

scholarly journals A comparison of foam rolling and vibration foam rolling on the quadriceps muscle function and mechanical properties

2021 ◽  
Author(s):  
Marina Maren Reiner ◽  
Christoph Glashüttner ◽  
Daniel Bernsteiner ◽  
Markus Tilp ◽  
Gael Guilhem ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Isometric Contraction ◽  
Vastus Lateralis ◽  
Shear Wave Elastography ◽  
Rectus Femoris ◽  
Peak Torque ◽  
Maximum Voluntary Isometric Contraction ◽  
Foam Rolling ◽  
Resistive Torque ◽  
Hip Extension

Abstract Purpose The purpose of the study was to investigate the effects of using a vibration foam roll (VFR) or a non-vibration foam roll (NVFR) on maximum voluntary isometric contraction peak torque (MVIC), range of motion (ROM), passive resistive torque (PRT), and shear modulus. Methods Twenty-one male volunteers visited the laboratory on two separate days and were randomly assigned to either a VFR group or a NVFR group. Both interventions were performed for 3 × 1 min each. Before and after each intervention, passive resistive torque and maximum voluntary isometric contraction peak torque of the leg extensors were assessed with a dynamometer. Hip extension ROM was assessed using a modified Thomas test with 3D-motion caption. Muscle shear modulus of the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) was assessed with shear wave elastography (SWE). Results In both groups (VFR, NVFR) we observed an increase in MVIC peak torque (+ 14.2 Nm, + 8.6 Nm) and a decrease in shear modulus of the RF (− 7.2 kPa, − 4.7 kPa). However, an increase in hip extension ROM (3.3°) was only observed in the VFR group. There was no change in PRT and shear modulus of the VL and VM, in both the VFR group and the NVFR group. Our findings demonstrate a muscle-specific acute decrease in passive RF stiffness after VFR and NVFR, with an effect on joint flexibility found only after VFR. Conclusion The findings of this study suggest that VFR might be a more efficient approach to maximize performance in sports with flexibility demands.

Legal Update: North Dakota Supreme Court: Third Edition of Guides is “Most Current”

1999 ◽  
Vol 4 (1) ◽  
pp. 6-7
Author(s):  
James J. Mangraviti
Keyword(s):  
Internal Rotation ◽  
External Rotation ◽  
Measurement Techniques ◽  
Fourth Edition ◽  
Hip Motion ◽  
The Difference ◽  
The Right ◽  
Hip Flexion ◽  
Hip Rotation ◽  
Hip Extension

Abstract The accurate measurement of hip motion is critical when one rates impairments of this joint, makes an initial diagnosis, assesses progression over time, and evaluates treatment outcome. The hip permits all motions typical of a ball-and-socket joint. The hip sacrifices some motion but gains stability and strength. Figures 52 to 54 in AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, illustrate techniques for measuring hip flexion, loss of extension, abduction, adduction, and external and internal rotation. Figure 53 in the AMA Guides, Fourth Edition, illustrates neutral, abducted, and adducted positions of the hip and proper alignment of the goniometer arms, and Figure 52 illustrates use of a goniometer to measure flexion of the right hip. In terms of impairment rating, hip extension (at least any beyond neutral) is irrelevant, and the AMA Guides contains no figures describing its measurement. Figure 54, Measuring Internal and External Hip Rotation, demonstrates proper positioning and measurement techniques for rotary movements of this joint. The difference between measured and actual hip rotation probably is minimal and is irrelevant for impairment rating. The normal internal rotation varies from 30° to 40°, and the external rotation ranges from 40° to 60°.

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