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 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.

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 Experience of application of T2-mapping MRI assessment of inflammatory myopathies

2020 ◽  
Vol 9 (3) ◽  
pp. 21-29
Author(s):  
O. B. Bogomyakova ◽  
M. A. Tavluy ◽  
A. A. Savelov
Keyword(s):  
Tibialis Anterior ◽  
Structural Changes ◽  
Vastus Lateralis ◽  
T2 Mapping ◽  
Rectus Femoris ◽  
Control Group ◽  
Inflammatory Myopathies ◽  
T2 Relaxation ◽  
Signal Characteristics ◽  
Lateral Head

Specialized quantitative MRI techniques allow identifying structural changes in individual muscles in inflammatory myopathies.Aim. To evaluate the role of T2 mapping MRI and to evaluate specific changes in T2 relaxation time in patients with inflammatory myopathies at different stages of the disease process.Methods. T2 mapping technique for assessing structural changes in muscle tissues was optimized for the Philips “Ingenia” 3.0T MR scanner. T2 relaxation (T2rt) time of the thigh and lower leg muscles (muscule rectus femoris, m. vastus lateralis, m. adductor magnus, m. soleus, m. tibialis anterior, medial and lateral head of m. gastrocnemius) was assessed in the control group (n = 9) and the study group (n = 6). Patients recruited in the study group suffered from dermatomyositis and polymyositis of various severity.Results. The following values of T2rt were obtained in the control group: m.rectus femoris – 78.2±6.9 ms, m.vastus lateralis – 79.5±4.8 ms, m.adductor magnus – 77.1±4.4 ms, m. soleus – 92.9±4.3 ms, m. tibialis anterior – 89.4±1.3 ms, m.gastrocnemius medial head – 93.7±2.4 ms, m.gastrocnemius lateral head – 92.9±3.5 ms. Patients with polymyositis and dermatomyositis showed an increase in the signal intensity on STIR and PD-SPAIR in the structure of m.soleus, m. gastrocmenius, m.rectus femoris, as well as a significant increase in T2rt of 40–49% (p<0.01). T2rt values did not differ in patients with polymyositis who received drug therapy and had clinical remission. Patients with dermatomyositis who had laboratory remission along with the deterioration reported an increase in T2rt in the structure of long spine muscles, m. rectus femoris and m. vastus lateralis equal to 15–25% (p<0.05). However, none significant changes in the signal characteristics on STIR and PDSPAIR were reported.Conclusion. The sensitivity of the reported technique in the detection of sub-acute swelling of muscle tissue in the absence of significant changes in signal characteristics on routine MR sequences had been shown. 

Muscle-specific atrophy of the quadriceps femoris with aging

2001 ◽  
Vol 90 (6) ◽  
pp. 2070-2074 ◽  
Author(s):  
T. A. Trappe ◽  
D. M. Lindquist ◽  
J. A. Carrithers
Keyword(s):  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Quadriceps Femoris ◽  
Aging Research ◽  
Cross Sectional ◽  
Men And Women ◽  
Younger Women ◽  
Vastus Intermedius ◽  
Aging Men ◽  
Old Men

We examined the size of the four muscles of the quadriceps femoris in young and old men and women to assess whether the vastus lateralis is an appropriate surrogate for the quadriceps femoris in human studies of aging skeletal muscle. Ten young (24 ± 2 yr) and ten old (79 ± 7 yr) sedentary individuals underwent magnetic resonance imaging of the quadriceps femoris after 60 min of supine rest. Volume (cm3) and average cross-sectional area (CSA, cm2) of the rectus femoris (RF), vastus lateralis (VL), vastus intermedius (VI), vastus medialis (VM), and the total quadriceps femoris were decreased ( P < 0.05) in older compared with younger women and men. However, percentage of the total quadriceps femoris taken up by each muscle was similar ( P > 0.05) between young and old (RF: 10 ± 0.3 vs. 11 ± 0.4; VL: 33 ± 1 vs. 33 ± 1; VI: 31 ± 1 vs. 31 ± 0.4; VM: 26 ± 1 vs. 25 ± 1%). These results suggest that each of the four muscles of the quadriceps femoris atrophy similarly in aging men and women. Our data support the use of vastus lateralis tissue to represent the quadriceps femoris muscle in aging research.

scholarly journals Regional and muscle-specific adaptations in knee extensor hypertrophy using flywheel versus conventional weight-stack resistance exercise

2019 ◽  
Vol 44 (8) ◽  
pp. 827-833 ◽  
Author(s):  
Tommy R. Lundberg ◽  
Maria T. García-Gutiérrez ◽  
Mirko Mandić ◽  
Mats Lilja ◽  
Rodrigo Fernandez-Gonzalo
Keyword(s):  
Resistance Exercise ◽  
Muscle Hypertrophy ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Knee Extensors ◽  
Cross Sectional ◽  
Proximal Site ◽  
Before And After

This study compared the effects of the most frequently employed protocols of flywheel (FW) versus weight-stack (WS) resistance exercise (RE) on regional and muscle-specific adaptations of the knee extensors. Sixteen men (n = 8) and women (n = 8) performed 8 weeks (2–3 days/week) of knee extension RE employing FW technology on 1 leg (4 × 7 repetitions), while the contralateral leg performed regular WS training (4 × 8–12 repetitions). Maximal strength (1-repetition maximum (1RM) in WS) and peak FW power were determined before and after training for both legs. Partial muscle volume of vastus lateralis (VL), vastus medialis (VM), vastus intermedius (VI), and rectus femoris (RF) were measured using magnetic resonance imaging. Additionally, quadriceps cross-sectional area was assessed at a proximal and a distal site. There were no differences (P > 0.05) between FW versus WS in muscle hypertrophy of the quadriceps femoris (8% vs. 9%), VL (10% vs. 11%), VM (6% vs. 8%), VI (5% vs. 5%), or RF (17% vs. 17%). Muscle hypertrophy tended (P = 0.09) to be greater at the distal compared with the proximal site, but there was no interaction with exercise method. Increases in 1RM and FW peak power were similar across legs, yet the increase in 1RM was greater in men (31%) than in women (20%). These findings suggest that FW and WS training induces comparable muscle-specific hypertrophy of the knee extensors. Given that these robust muscular adaptations were brought about with markedly fewer repetitions in the FW compared with WS, it seems FW training can be recommended as a particularly time-efficient exercise paradigm.

scholarly journals The Effect of Crank Length Changes from Cycling Rehabilitation on Muscle Behaviors

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Lu Zongxing ◽  
You Shengxian ◽  
Wei Xiangwen ◽  
Chen Xiaohui ◽  
Jia Chao
Keyword(s):  
Tibialis Anterior ◽  
Vastus Lateralis ◽  
Length Distribution ◽  
Rectus Femoris ◽  
Inverse Kinematic ◽  
Muscle Group ◽  
Type Model ◽  
Length Changes ◽  
The Relationship ◽  
Crank Length

Background. Many sports and physical activities can result in lower limb injures. Pedaling is an effective exercise for lower extremity rehabilitation, but incorrect technique may cause further damage. To some extent, previous experiments have been susceptible to bias in the sample recruited for the study. Alternatively, methods used to simulation activities can enable parametric studies without the influence of noise. In addition, models can facilitate the study of all muscles in the absence of the effects of fatigue. This study investigated the effects of crank length on muscle behavior during pedaling. Methods. Six muscles (soleus, tibialis anterior, vastus medialis, vastus lateralis, gastrocnemius, and rectus femoris), divided into three groups (ankle muscle group, knee muscle group, and biarticular muscle group), were examined under three cycling crank lengths (100 mm, 125 mm, and 150 mm) in the present study. In addition, the relationship between crank length and muscle biological force was analyzed with the AnyBody Modeling System™, a human simulation modeling software based on the Hill-type model. Findings. Based on inverse kinematic analysis, the results indicate that muscle activity and muscle force decrease in varying degrees with increases in crank length. The maximum and minimum muscular forces were attained in the tibialis anterior and vastus lateralis, respectively. Interpretation. Studying the relationship between muscle and joint behavior with crank length can help rehabilitation and treating joint disorders. This study provides the pedal length distribution areas for patients in the early stages of rehabilitation.

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