Normalisation of a biarticular muscle EMG signal using a submaximal voluntary contraction: choice of the standardised isometric task for the rectus femoris, a pilot study.

In studying the effects of expertise on different performance aspects of the gymnastic vault event, various springboard types with similar compression forces were evaluated between expert and novice-level gymnasts. Surface EMGs (sEMG) were placed on four major muscles (biceps femoris, rectus femoris, gastrocnemius medialis, and tibialis anterior) to find each gymnasts’ maximum voluntary contraction. Similarly, board compression and knee flexion angles were also captured at various phases of the performed vaults. Given that gymnasts with more expertise were more consistent in their landing spot on the various vault boards, they had more consistent performance outputs as a result. Expert gymnasts did this by more accurately hitting the sweet spot, more consistently activating their hamstring and gastrocnemius, and decreasing variability during the initial contact phase. By doing this, board compression and performance were both optimized. Coaches can use this information to accelerate the development of novice gymnasts by targeting these aspects.

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Alternate muscle activity observed between knee extensor synergists during low-level sustained contractions

Journal of Applied Physiology ◽

10.1152/japplphysiol.00764.2001 ◽

2002 ◽

Vol 93 (2) ◽

pp. 675-684 ◽

Cited By ~ 68

Author(s):

Motoki Kouzaki ◽

Minoru Shinohara ◽

Kei Masani ◽

Hiroaki Kanehisa ◽

Tetsuo Fukunaga

Keyword(s):

Muscle Activity ◽

Vastus Lateralis ◽

Force Production ◽

Knee Extensor ◽

Rectus Femoris ◽

Quadriceps Muscle ◽

Knee Extension ◽

Voluntary Contraction ◽

Low Level ◽

Integrated Emg

To determine quantitatively the features of alternate muscle activity between knee extensor synergists during low-level prolonged contraction, a surface electromyogram (EMG) was recorded from the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) in 11 subjects during isometric knee extension exercise at 2.5% of maximal voluntary contraction (MVC) for 60 min ( experiment 1). Furthermore, to examine the relation between alternate muscle activity and contraction levels, six of the subjects also performed sustained knee extension at 5.0, 7.5, and 10.0% of MVC ( experiment 2). Alternate muscle activity among the three muscles was assessed by quantitative analysis on the basis of the rate of integrated EMG sequences. In experiment 1, the number of alternations was significantly higher between RF and either VL or VM than between VL and VM. Moreover, the frequency of alternate muscle activity increased with time. In experiment 2, alternating muscle activity was found during contractions at 2.5 and 5.0% of MVC, although not at 7.5 and 10.0% of MVC, and the number of alternations was higher at 2.5 than at 5.0% of MVC. Thus the findings of the present study demonstrated that alternate muscle activity in the quadriceps muscle 1) appears only between biarticular RF muscle and monoarticular vasti muscles (VL and VM), and its frequency of alternations progressively increases with time, and 2) emerges under sustained contraction with force production levels ≤5.0% of MVC.

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Impact of a Carbohydrate Mouth Rinse on Quadriceps Muscle Function and Corticomotor Excitability

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2018-0583 ◽

2019 ◽

Vol 14 (7) ◽

pp. 927-933 ◽

Cited By ~ 1

Author(s):

Stephen P. Bailey ◽

Julie Hibbard ◽

Darrin La Forge ◽

Madison Mitchell ◽

Bart Roelands ◽

...

Keyword(s):

Evoked Potential ◽

Motor Evoked Potential ◽

Rectus Femoris ◽

Quadriceps Muscle ◽

Voluntary Contraction ◽

Muscle Performance ◽

Mouth Rinse ◽

Motor Excitability ◽

The Right ◽

Relative Change

Background: Carbohydrate (CHO) mouth rinse (MR) before exercise has been shown to improve physical performance and corticospinal motor excitability. Purpose: To determine the effects of different forms of CHO MR on quadriceps muscle performance and corticospinal motor excitability. Methods: 10 subjects (5 female and 5 male; 25 [1] y, 1.71 [0.03] m, 73 [5] kg) completed 4 conditions (placebo [PLA], 6.4% glucose [GLU], 6.4% maltose [MAL], 6.4% maltodextrin [MDX]). Maximal voluntary contraction (MVIC) of the right quadriceps and motor-evoked potential (MEP) of the right rectus femoris was determined pre (10 min), immediately after, and post (10 min) 20-s MR. MEP was precipitated by transcranial magnetic stimulation during muscle contraction (50% MVIC). Results: The relative change in MEP from pre-measures was different across treatments (P = .025) but was not different across time (P = .357). MEP was greater for all CHO conditions immediately after (GLU = 2.58% [5.33%], MAL = 3.92% [3.90%], MDX = 18.28% [5.57%]) and 10 min after (GLU = 14.09% [13.96%], MAL = 8.64% [8.67%], MDX = 31.54% [12.77%]) MR than PLA (immediately after = −2.19% [4.25%], 10 min = −13.41% [7.46%]). MVC was greater for CHO conditions immediately (GLU = 3.98% [2.49%], MAL = 5.89% [2.29%], MDX = 7.66% [1.93%]) and 10 min after (GLU = 7.22% [2.77%], MAL = 10.26% [4.22%], MDX = 10.18% [1.50%]) MR than PLA (immediately after = −3.24% [1.50%], 10 min = −6.46% [2.22%]). Conclusions: CHO MR increased corticospinal motor excitability and quadriceps muscle after application. The form of CHO used did not influence this response.

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Test-retest reliability of electromyographic signal parameters used to evaluate neuromuscular fatigue in quadriceps femoris muscle

Kinesiology ◽

10.26582/k.48.2.14 ◽

2016 ◽

Vol 48 (2) ◽

pp. 174-181 ◽

Cited By ~ 1

Author(s):

Cristiano Rocha da Silva ◽

Danilo de Oliveira Silva ◽

Ronaldo Valdir Briani ◽

Marcella Ferraz Pazzinatto ◽

Deisi Ferrari ◽

...

Keyword(s):

Vastus Lateralis ◽

Rectus Femoris ◽

Neuromuscular Fatigue ◽

Median Frequency ◽

Endurance Time ◽

Retest Reliability ◽

Emg Signal ◽

Electromyographic Signal ◽

Test Retest Reliability ◽

Voluntary Contractions

The purpose of this study was to analyze the test-retest reliability of the median frequency (MDF) and root mean square (RMS) used to determine the onset of neuromuscular fatigue (NF) during sustained fatiguing contractions of the quadriceps. Eighteen healthy men were tested on two days, and electromyographic (EMG) signals were recorded from the vastus medialis (VM), rectus femoris (RF) and vastus lateralis (VL) during sustained isometric contractions at 20 and 70% of maximum voluntary contractions (MVC) held until exhaustion. The reliability of endurance time was excellent at 20% MVC and poor at 70% MVC. EMG variables were evaluated: (1) at the beginning of the test; (2) at NF; and (3) at the end of the test. The NF time values presented poor reliability. The MDF has shown, in general, poor reliability at 20 and 70% MVC, whereas the RMS reliability presented better results for both loads, especially for RF, followed by the VM and VL muscles. The MDF and RMS values extracted from NF showed poor reliability at 20 and 70% MVC, which suggests caution in using these variables extracted from the EMG signal to determine the onset of NF.

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

Journal of Applied Physiology ◽

10.1152/japplphysiol.01309.2005 ◽

2006 ◽

Vol 101 (3) ◽

pp. 715-720 ◽

Cited By ~ 37

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.

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Decrease in maximal voluntary contraction by tonic vibration applied to a single synergist muscle in humans

Journal of Applied Physiology ◽

10.1152/jappl.2000.89.4.1420 ◽

2000 ◽

Vol 89 (4) ◽

pp. 1420-1424 ◽

Cited By ~ 65

Author(s):

Motoki Kouzaki ◽

Minoru Shinohara ◽

Tetsuo Fukunaga

Keyword(s):

Maximal Voluntary Contraction ◽

Vastus Lateralis ◽

Rectus Femoris ◽

Knee Extension ◽

Voluntary Contraction ◽

Vastus Medialis ◽

Force Development ◽

Ia Afferent ◽

Before And After ◽

Integrated Emg

The purpose of the study was to examine the effect of prolonged tonic vibration applied to a single synergist muscle on maximal voluntary contraction (MVC) and maximal rate of force development (dF/d t max). The knee extension MVC force and surface electromyogram (EMG) from the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) during MVC were recorded before and after vibration of RF muscle at 30 Hz for 30 min. MVC, dF/d t max, and the integrated EMG (iEMG) of RF decreased significantly after prolonged tonic vibration in spite of no changes in iEMG of VL and VM. The present results indicate that MVC and dF/d t max may be influenced by the attenuated Ia afferent functions of a single synergist muscle.

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MON-LB318: Agreement between Rectus Femoris Muscle Thickness by Ultrasound and Skeletal Muscle Mass by Bio-Electrical Impedance Analysis: A Pilot Study

Clinical Nutrition ◽

10.1016/s0261-5614(17)31108-1 ◽

2017 ◽

Vol 36 ◽

pp. S296

Author(s):

I.L. Rodenburg ◽

W. Nijholt ◽

M.J. Sealy ◽

C.P. van de Schans ◽

J.S. Hobbelen ◽

...

Keyword(s):

Skeletal Muscle ◽

Pilot Study ◽

Muscle Mass ◽

Skeletal Muscle Mass ◽

Electrical Impedance ◽

Muscle Thickness ◽

Rectus Femoris ◽

Impedance Analysis ◽

Rectus Femoris Muscle ◽

Femoris Muscle

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State-of-the-Art Method in Prosthetic Hand Design: A Review

Journal of Biomimetics Biomaterials and Biomedical Engineering ◽

10.4028/www.scientific.net/jbbbe.50.15 ◽

2021 ◽

Vol 50 ◽

pp. 15-24

Author(s):

T. Triwiyanto ◽

Triana Rahmawati ◽

I. Putu Alit Pawana ◽

L. Lamidi ◽

Torib Hamzah ◽

...

Keyword(s):

Low Power ◽

Low Cost ◽

Maximum Voluntary Contraction ◽

Voluntary Contraction ◽

Occupational Accidents ◽

Limb Amputation ◽

Prosthetic Hand ◽

Advantages And Disadvantages ◽

Prosthetic Hands ◽

Emg Signal

Human limb amputation can be caused due to congenital disabilities, accidents, and certain diseases. Amputation caused by occupational accidents is a frequent occurrence in developing countries. Meanwhile, amputation caused by certain diseases such as diabetes Miletus is also the leading cause. The need for prosthetic hand is increasing along with the increase in those two factors. Several researchers have developed prosthetic hands with advantages and disadvantages. Research on prosthetic hands, which are useful, low power, and low cost, is still a major issue. Therefore, the purpose of this paper is to provide a review of the various designs of prosthetic hands, specifically on the sensor, control, and actuator systems. This paper collected several references from proceedings and journals related to the design of the prosthetic hand. The results show that the EMG signal is widely used by some researchers in controlling prosthetic hands compared to other sensors, following the force-sensitive resistor (FSR) sensor. To control prosthetic hands, some researchers used a threshold system with a value of 20% of the maximum voluntary contraction (MVC), and several other researchers used a pattern recognition model based on the EMG signal feature. Moreover, In the mechanical part, the open-source prosthetic hand model is more widely used than the fabricate prosthetic hand. This is due to the cost required in the prosthetic hand design is cheaper than a fabricated one. The results of this review are expected to provide a recommendation to researchers in the development of low cost, low power, and practical prosthetic hands.

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Motor Unit Interpulse Intervals During High Force Contractions

Motor Control ◽

10.1123/mc.2014-0089 ◽

2016 ◽

Vol 20 (1) ◽

pp. 70-86 ◽

Cited By ~ 4

Author(s):

Matt S. Stock ◽

Brennan J. Thompson

Keyword(s):

Motor Unit ◽

Polynomial Regression ◽

Vastus Lateralis ◽

Motor Units ◽

Surface Emg ◽

Voluntary Contraction ◽

Emg Signal ◽

Coefficients Of Variation ◽

Low Threshold ◽

The Relationship

We examined the means, medians, and variability for motor-unit interpulse intervals (IPIs) during voluntary, high force contractions. Eight men (mean age = 22 years) attempted to perform isometric contractions at 90% of their maximal voluntary contraction force while bipolar surface electromyographic (EMG) signals were detected from the vastus lateralis and vastus medialis muscles. Surface EMG signal decomposition was used to determine the recruitment thresholds and IPIs of motor units that demonstrated accuracy levels ≥ 96.0%. Motor units with high recruitment thresholds demonstrated longer mean IPIs, but the coefficients of variation were similar across all recruitment thresholds. Polynomial regression analyses indicated that for both muscles, the relationship between the means and standard deviations of the IPIs was linear. The majority of IPI histograms were positively skewed. Although low-threshold motor units were associated with shorter IPIs, the variability among motor units with differing recruitment thresholds was comparable.

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