scholarly journals Antagonist Muscle Co-Activation during Kettlebell Single Arm Swing Exercise

2021 ◽  
Vol 11 (9) ◽  
pp. 4033
Author(s):  
Ahmed Salem ◽  
Amr Hassan ◽  
Markus Tilp ◽  
Abdel-Rahman Akl
Keyword(s):  
Muscle Activation ◽  
Surface Emg ◽  
Antagonist Muscle ◽  
Arm Swing ◽  
Shoulder Muscles ◽  
Antagonist Muscles ◽  
Co Activation ◽  
Integrated Emg ◽  
Post Hoc ◽  
Electrical Muscle

The purpose of this study was to determine the muscle activation and co-activation of selected muscles during the kettlebell single arm swing exercise. To the best of our knowledge, this is the first study investigating the muscle co-activation of a kettlebell single arm swing exercise. Nine volunteers participated in the present study (age: 22.6 ± 3.8 years; body mass: 80.4 ± 9.2 kg; height: 175.6 ± 7.5 cm). The electrical muscle activity of eight right agonist/antagonist muscles (AD/PD, ESL/RA, ESI/EO, and GM/RF) were recorded using a surface EMG system (Myon m320RX; Myon, Switzerland) and processed using the integrated EMG to calculate a co-activation index (CoI) for the ascending and descending phases. A significant effect of the ascending and descending phases on the muscles’ CoI was observed. Post hoc analyses showed that the co-activation was significantly higher in the descending phase compared to that in the ascending phase of AD/PD CoI (34.25 ± 18.03% and 24.75 ± 13.03%, p < 0.001), ESL/RA CoI (34.97 ± 17.86% and 24.19 ± 10.32%, p < 0.001), ESI/EO CoI (41.14 ± 10.72% and 30.87 ± 11.26%, p < 0.001), and GM/RF CoI (27.49 ± 12.97% and 34.98 ± 14.97%, p < 0.001). In conclusion, the co-activation of the shoulder muscles varies within the kettlebell single arm swing. The highest level of co-activation was observed in the descending phase of AD/PD and GM/RF CoI, and the lowest level of co-activation was observed during the descending phase, ESL/RA and ESI/EO CoI. In addition, the highest level of co-activation was observed in the ascending phase of ESL/RA and ESI/EO CoI, and the lowest level of co-activation was observed during the ascending phase, AD/PD and GM/RF CoI. The co-activation index could be a useful method for the interpretation of the shoulder and core muscles’ co-activity during a kettlebell single arm swing.

scholarly journals Quantifying Coordination between Agonist and Antagonist Elbow Muscles during Backhand Crosscourt Shots in Adult Female Squash Players

2021 ◽  
Vol 18 (18) ◽  
pp. 9825
Author(s):  
Abdel-Rahman Akl ◽  
Amr Hassan ◽  
Helal Elgizawy ◽  
Markus Tilp
Keyword(s):  
Adult Female ◽  
Biceps Brachii ◽  
Surface Emg ◽  
Triceps Brachii ◽  
Execution Phase ◽  
Co Activation ◽  
Significant Difference ◽  
Preparation Phase ◽  
Agonist And Antagonist ◽  
Integrated Emg

The purpose of this study was to quantify the coordination between agonist and antagonist elbow muscles during squash backhand crosscourt shots in adult female players. Ten right-handed, international-level, female squash players participated in the study. The electrical muscle activity of two right elbow agonist/antagonist muscles, the biceps brachii and triceps brachii, were recorded using a surface EMG system, and processed using the integrated EMG to calculate a co-activation index (CoI) for the preparation phase, the execution phase, and the follow-through phase. A significant effect of the phases on the CoI was observed. Co-activation was significantly different between the follow-through and the execution phase (45.93 ± 6.00% and 30.14 ± 4.11%, p < 0.001), and also between the preparation and the execution phase (44.74 ± 9.88% and 30.14 ± 4.11%, p < 0.01). No significant difference was found between the preparation and the follow-through phase (p = 0.953). In conclusion, the co-activation of the elbow muscles varies within the squash backhand crosscourt shots. The highest level of co-activation was observed in the preparation phase and the lowest level of co-activation was observed during the execution. The co-activation index could be a useful method for the interpretation of elbow muscle co-activity during a squash backhand crosscourt shot.

scholarly journals Efeitos agudos da utilização de dispositivos geradores de instabilidade externa sobre o desempenho neuromuscular

2016 ◽  
Vol 18 (6) ◽  
pp. 722
Author(s):  
Guillermo Peña García-Orea ◽  
Marta Silva Santos ◽  
Juan Ramón Heredia Elvar ◽  
Marzo Edir Da Silva-Grigoletto
Keyword(s):  
Muscle Activation ◽  
Lower Limbs ◽  
Middle Zone ◽  
Joint Stability ◽  
Acute Effects ◽  
Force Output ◽  
Sport Training ◽  
Health Area ◽  
Antagonist Muscles ◽  
Co Activation

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n6p722 Physical training with the use of instability generator devices has become popular in the health area, in sport training and clinical practice (mainly in the prevention and treatment of injuries). To understand how the process of using these devices occurs and the results of their acute effects is important to guide professionals in choosing the appropriate device. The aim of this review was to present the main features of instability devices and analyze their acute effects on core muscle activation, neuromuscular performance and activation of lower and upper limbs. Studies have shown that the main acute effects of exercises performed with these devices are: 1) increased activation / muscular recruitment (especially in the middle zone or core); 2) greater co-activation of antagonist muscles (trunk, upper and lower limbs), with increased stiffness and joint stability; 3) lower force output, power and speed in extremities.

Efference copy in kinesthetic perception: A copy of what is it?

2021 ◽  
Author(s):  
Mark L. Latash
Keyword(s):  
Neural Control ◽  
Efference Copy ◽  
Single Element ◽  
Muscle Vibration ◽  
Sense Of Effort ◽  
Antagonist Muscles ◽  
Co Activation ◽  
Lower Accuracy ◽  
Neural Control Of Movement ◽  
Kinesthetic Perception

A number of notions in the fields of motor control and kinesthetic perception have been used without clear definitions. In this review, we consider definitions for efference copy, percept, and sense of effort based on recent studies within the physical approach, which assumes that the neural control of movement is based on principles of parametric control and involves defining time-varying profiles of spatial referent coordinates for the effectors. The apparent redundancy in both motor and perceptual processes is reconsidered based on the principle of abundance. Abundance of efferent and afferent signals is viewed as the means of stabilizing both salient action characteristics and salient percepts formalized as stable manifolds in high-dimensional spaces of relevant elemental variables. This theoretical scheme has led recently to a number of novel predictions and findings. These include, in particular, lower accuracy in perception of variables produced by elements involved in a multi-element task compared to the same elements in single-element tasks, dissociation between motor and perceptual effects of muscle co-activation, force illusions induced by muscle vibration, and errors in perception of unintentional drifts in performance. Taken together, these results suggest that participation of efferent signals in perception frequently involves distorted copies of actual neural commands, particularly those to antagonist muscles. Sense of effort is associated with such distorted efferent signals. Distortions in efference copy happen spontaneously and can also be caused by changes in sensory signals, e.g., those produced by muscle vibration.

Initial phase of maximal voluntary and electrically stimulated knee extension torque development at different knee angles

2004 ◽  
Vol 97 (5) ◽  
pp. 1693-1701 ◽  
Author(s):  
C. J. de Ruiter ◽  
R. D. Kooistra ◽  
M. I. Paalman ◽  
A. de Haan
Keyword(s):  
Muscle Activation ◽  
Knee Extensor ◽  
Surface Emg ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Knee Angle ◽  
Time Integral ◽  
Voluntary Contractions ◽  
Torque Development

We investigated the capacity for torque development and muscle activation at the onset of fast voluntary isometric knee extensions at 30, 60, and 90° knee angle. Experiments were performed in subjects ( n = 7) who had high levels (>90%) of activation at the plateau of maximal voluntary contractions. During maximal electrical nerve stimulation (8 pulses at 300 Hz), the maximal rate of torque development (MRTD) and torque time integral over the first 40 ms (TTI40) changed in proportion with torque at the different knee angles (highest values at 60°). At each knee angle, voluntary MRTD and stimulated MRTD were similar ( P < 0.05), but time to voluntary MRTD was significantly longer. Voluntary TTI40 was independent ( P > 0.05) of knee angle and on average (all subjects and angles) only 40% of stimulated TTI40. However, among subjects, the averaged (across knee angles) values ranged from 10.3 ± 3.1 to 83.3 ± 3.2% and were positively related ( r2 = 0.75, P < 0.05) to the knee-extensor surface EMG at the start of torque development. It was concluded that, although all subjects had high levels of voluntary activation at the plateau of maximal voluntary contraction, among subjects and independent of knee angle, the capacity for fast muscle activation varied substantially. Moreover, in all subjects, torque developed considerably faster during maximal electrical stimulation than during maximal voluntary effort. At different knee angles, stimulated MRTD and TTI40 changed in proportion with stimulated torque, but voluntary MRTD and TTI40 changed less than maximal voluntary torque.

scholarly journals The influence of temporal predictability on express visuomotor responses

2020 ◽  
Author(s):  
Samuele Contemori ◽  
Gerald E. Loeb ◽  
Brian D. Corneil ◽  
Guy Wallis ◽  
Timothy J. Carroll
Keyword(s):  
Superior Colliculus ◽  
Onset Time ◽  
Surface Emg ◽  
Stimulus Onset ◽  
Target Motion ◽  
Target Velocity ◽  
Moving Target ◽  
Visuomotor Transformations ◽  
Shoulder Muscles ◽  
Temporal Predictability

ABSTRACTVolitional visuomotor responses in humans are generally thought to manifest 100ms or more after stimulus onset. Under appropriate conditions, however, much faster target-directed responses can be produced at upper limb and neck muscles. These “express” responses have been termed stimulus-locked responses (SLRs) and are proposed to be modulated by visuomotor transformations performed subcortically via the superior colliculus. Unfortunately, for those interested in studying SLRs, these responses have proven difficult to detect consistently across individuals. The recent report of an effective paradigm for generating SLRs in 100% of participants appears to change this. The task required the interception of a moving target that emerged from behind a barrier at a time consistent with the target velocity. Here we aimed to reproduce the efficacy of this paradigm for eliciting SLRs and to test the hypothesis that its effectiveness derives from the predictability of target onset time as opposed to target motion per se. In one experiment, we recorded surface EMG from shoulder muscles as participants made reaches to intercept temporally predictable or unpredictable targets. Consistent with our hypothesis, predictably timed targets produced more frequent and stronger SLRs than unpredictably timed targets. In a second experiment, we compared different temporally predictable stimuli and observed that transiently presented targets produced larger and earlier SLRs than sustained moving targets. Our results suggest that target motion is not critical for facilitating the expression of an SLR and that timing predictability does not rely on extrapolation of a physically plausible motion trajectory. These findings provide support for a mechanism whereby an internal timer, probably located in cerebral cortex, primes the processing of both visual input and motor output within the superior colliculus to produce SLRs.

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.

Intent-Related Differences in Surface EMG of Maximum Eccentric and Concentric Contractions

2003 ◽  
Vol 19 (2) ◽  
pp. 99-105 ◽  
Author(s):  
Mark D. Grabiner ◽  
Tammy M. Owings
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Eccentric Contraction ◽  
Surface Emg ◽  
Vastus Lateralis Muscle ◽  
Concentric Contractions ◽  
Concentric Contraction ◽  
Contraction Condition ◽  
The Difference

For this study it was hypothesized that when participants intended to perform a maximum voluntary concentric (or eccentric) contraction but had an eccentric (or concentric) contraction imposed upon them, the initial EMG measured during the isometric phase preceding the onset of the dynamometer motion would reflect the intended contraction condition. The surface EMG of the vastus lateralis muscle was measured in 24 participants performing isokinetic concentric and eccentric maximum voluntary knee extensor contractions. The contractions were initiated from rest and from the same knee flexion angle and required the same level of external force to trigger the onset of dynamometer motion. Vastus lateralis EMG were quantified during the isometric phase preceding the onset of the dynamometer motion. When participants intended to perform a concentric contraction but had an eccentric contraction imposed upon them, the initial EMG resembled that of a concentric contraction. When they intended to perform an eccentric contraction but had a concentric contraction imposed upon them, the initial EMG resembled that of an eccentric contraction. Overall, the difference between concentric and eccentric contractions observed during the period of theinitialmuscle activation implies that descending signals include information that distinguishes between eccentric and concentric contractions.

scholarly journals Estimation of muscle activation during different walking speeds with two mathematical approaches compared to surface EMG

2018 ◽  
Vol 64 ◽  
pp. 266-273 ◽  
Author(s):  
Ursula Trinler ◽  
Fabien Leboeuf ◽  
Kristen Hollands ◽  
Richard Jones ◽  
Richard Baker
Keyword(s):  
Muscle Activation ◽  
Surface Emg ◽  
Walking Speeds

Evaluation of Muscle Activities on Different Type of Exercises During Prolonged Sitting

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Mohammad Shahril Salim ◽  
◽  
Nor Fatihah Fujrah Mohd Nawi ◽  
Ahmad Faizal Salleh ◽  
Nurhidayah Omar ◽  
...  
Keyword(s):  
Back Pain ◽  
Muscle Activation ◽  
Erector Spinae ◽  
Prolonged Sitting ◽  
Emg Signal ◽  
Different Types ◽  
Muscle Activations ◽  
Internal Oblique ◽  
Electrical Muscle

Electromyography (EMG) signal is an analysis of electrical signals generated during muscular contractions that have been used to measure and record electrical muscle activity usually applied for medical tests. In this research EMG signal is used to; (1) evaluate muscle activations on different gender during prolonged sitting task; (2) investigate the influence of various types of exercise during prolonged sitting on muscle activation and (3) proposed the best exercise that can help to prevent low back discomfort. Twenty subjects (10 males and 10 females) were recruited from undergraduate engineering student’s education background in UniMAP with age ranging between 20 to 24 years old. The subject must be asymptomatic back pain, normal BMI and right-handed. . Three different types of sitting, one hour per sitting were done by each subject in order to reach the goals of this study. First sitting (sitting without exercise) was conducted while second and third sitting (sitting with exercise) were done in order the investigate the effectiveness of the exercises. Two different types of exercise were performed in second and third sitting, both of exercises were chosen from Mc Kenzie’s exercise. EEGOTM sport device were used to record the EMG signal from four types of muscles which are Erector Spinae, Latissimus Dorsi, Internal Oblique and External Oblique. By comparing the Root Mean Square (RMS) values from EMG signals muscle activation during prolonged sitting and the effectiveness of performing the exercises have been evaluated based on RMS values. As the results, muscle become deactivate during prolonged sitting. The best exercise to reduce back pain discomfort is exercise type 1 (Seated Lumbar Exercise) and it is recommended to perform this exercise regularly to reduce the risk of getting hazardous disease due to prolonged sitting.

Muscle Activity Before and After Subacromial Injection

2021 ◽  
pp. 1-7
Author(s):  
Lucas Ettinger ◽  
Matthew Shaprio ◽  
Andrew Karduna
Keyword(s):  
Rotator Cuff ◽  
Muscle Activation ◽  
Rotator Cuff Tears ◽  
Subacromial Impingement ◽  
Upper Trapezius ◽  
Subacromial Injection ◽  
Shoulder Muscle ◽  
Shoulder Muscles ◽  
Before And After ◽  
Arm Elevation

Context: Shoulder muscle activation in patients with subacromial impingement is highly cited and variable in the literature. Differences between studies could be due to artifacts introduced by normalization practices in the presence of pain. Ultimately, this lack of knowledge pertaining to pathogenesis limits the clinical treatment and restoration of muscular function. Design: A total of 21 patients with stage 2 subacromial impingement and 21 matched controls were recruited for EMG testing of their affected shoulder during an arm elevation task. The patients were tested before and after receiving an injection to their subacromial bursa. Methods: The EMG from 7 shoulder muscles were measured before and after treatment during humeral motion in the scapular plane. Results: Our findings indicate an increase in anterior deltoid, middle deltoid, and upper trapezius activity following the injection; further, this trend extended to the controls. The control subjects had a greater activation of the latissimus dorsi at peak arm elevation when compared with the patient group postinjection. Conclusions: Our results indicate that a reduction in subacromial pain is associated with changes in shoulder muscle recruitment, primarily of the deltoid. This change in deltoid activity may lend evidence to rotator cuff function in patients without rotator cuff tears.

Sign in / Sign up

Export Citation Format

Share Document