Surface Electromyography Measurements Research Articles

Investigation of graphene-coated Ag/AgCl electrode performance in surface electromyography measurement

Conventional silver-silver chloride (Ag/AgCl) electrodes are widely used for recording surface electromyography (sEMG) with a conductive gel. However, for long-term sEMG recording, the gel has some disadvantages that cause high impedance. Therefore, the dry electrodes have been alternatively purposed to overcome these disadvantages. Recently, the nanomaterial-based dry electrodes have been developed for long term electrophysiological signal recording. In the present study, we aimed to develop a graphene-coated Ag/AgCl electrode for long-term recording. We transferred single layer graphene (SLG) on the Ag/AgCl electrode surface by using chemical vapor deposition and confirmed this process by Raman scattering spectroscopy and scanning electron microscopy. We then compared the graphene-coated Ag/AgCl and conventional Ag/AgCl electrodes by evaluating median motor nerve conduction studies (mNCS) and their impedance. The charge transfer resistance (Rct) for the Ag/AgCl electrode (4170 Ω) was much higher than graphene-coated Ag/AgCl electrode (Rct = 24.6 Ω). For median mNCS measurements without gel, the graphene-coated Ag/AgCl electrode provided a better amplitude of distal and proximal compound muscle action potential (28.3 mV and 25.8 mV, respectively) than the Ag/AgCl electrode (21.8 mV and 20.9 mV, respectively). Consequently, the present study suggests promising results in terms of the usability of graphene-coated Ag/AgCl electrodes for long-term monitoring and wearable systems applications of sEMG. In future studies, we aim to investigate clinical applicability of graphene-coated sEMG electrodes that include extended clinical settings and larger study population.

Stretchable electronic skin patch with strain isolation for the simultaneous measurements of surface electromyography and temperature

Stretchable electronic skin patches have continuously attracted the attention of researchers and clinicians due to their potentials in medical applications. Despite the remarkable progress of electronic skin patches with diverse sensor modalities for regions undergoing small deformations, the electronic skin patch in a stretchable format for regions requiring large strain accommodations has far less been explored. Here, we report a stretchable electronic skin patch with strain isolation for the simultaneous measurement of surface electromyography (sEMG) and temperature. The electronic skin patch consists of two mesh-like sEMG electrodes and one resistance temperature sensor on a compliant substrate with programmable stiffness induced by the spatioselective ultraviolet exposure. This construct allows for mechanical softness of electrodes for an intimate attachment to skin and isolation of deformation-induced disturbances and damages to the temperature sensor. Experimental and numerical studies reveal the design, fabrication and operation of the skin patch. Demonstration of the skin patch with strain isolation on the lumbar muscle groups during the trunk flexion, which may introduce a 20% strain level, illustrates its robust capabilities for the comprehensive assessment of muscle activities with possibilities to study the temperature effect on sEMG signals. The results reported here provide important inspiration for constructing multifunctional electronic skin patches with a wide range of applications such as health-monitoring devices, wearable human-machine interface and clinical muscle function evaluation.

Toward reanimating the laughter-involved large-scale brain networks to alleviate affective symptoms.

IntroductionThe practicality of the idea whether the laughter‐involved large‐scale brain networks can be stimulated to remediate affective symptoms, namely depression, has remained elusive.MethodsIn this study, 25 healthy individuals were tested through 21‐channel quantitative electroencephalography (qEEG) setup upon resting state and while submitted to standardized funny video clips (corated by two behavioral neuroscientists and a verified expert comedian, into neutral and mildly to highly funny). We evaluated the individuals’ facial expressions against the valence and intensity of each stimulus through the Nuldos face analysis software. The study also employed an eye‐tracking setup to examine fixations, gaze, and saccadic movements upon each task. In addition, changes in polygraphic parameters were monitored upon resting state and exposure to clips using the 4‐channel Nexus polygraphy setup.ResultsThe happy facial expression analysis, as a function of rated funny clips, showed a significant difference against neutral videos (p < 0.001). In terms of the polygraphic changes, heart rate variability and the trapezius muscle surface electromyography measures were significantly higher upon exposure to funny vs. neutral videos (p < 0.5). The average pupil size and fixation drifts were significantly higher and lower, respectively, upon exposure to funny videos (p < 0.01). The qEEG data revealed the highest current source density (CSD) for the alpha frequency band localized in the left frontotemporal network (FTN) upon exposure to funny clips. Additionally, left FTN acquired the highest value for theta coherence z‐score, while the beta CSD predominantly fell upon the salience network (SN).ConclusionsThese preliminary data support the notion that left FTN may be targeted as a cortical hub for noninvasive neuromodulation as a single or adjunct therapy in remediating affective disorders in the clinical setting. Further studies are needed to test the hypotheses derived from the present report.

Changes in elbow flexion EMG morphology during adjustment of deep brain stimulator in advanced Parkinson's disease.

Deep brain stimulation (DBS) is an effective treatment for motor symptoms of advanced Parkinson's disease (PD). Currently, DBS programming outcome is based on a clinical assessment. In an optimal situation, an objectively measurable feature would assist the operator to select the appropriate settings for DBS. Surface electromyographic (EMG) measurements have been used to characterise the motor symptoms of PD with good results; with proper methodology, these measurements could be used as an aid to program DBS. Muscle activation measurements were performed for 13 patients who had advanced PD and were treated with DBS. The DBS pulse voltage, frequency, and width were changed during the measurements. The measured EMG signals were analysed with parameters that characterise the EMG signal morphology, and the results were compared to the clinical outcome of the adjustment. The EMG signal correlation dimension, recurrence rate, and kurtosis changed significantly when the DBS settings were changed. DBS adjustment affected the signal recurrence rate the most. Relative to the optimal settings, increased recurrence rates (median ± IQR) 1.1 ± 0.5 (-0.3 V), 1.3 ± 1.1 (+0.3 V), 1.7 ± 0.4 (-30 Hz), 1.7 ± 0.8 (+30 Hz), 2.0 ± 1.7 (+30 μs), and 1.5 ± 1.1 (DBS off) were observed. With optimal stimulation settings, the patients' Unified Parkinson's Disease Rating Scale motor part (UPDRS-III) score decreased by 35% on average compared to turning the device off. However, the changes in UPRDS-III arm tremor and rigidity scores did not differ significantly in any settings compared to the optimal stimulation settings. Adjustment of DBS treatment alters the muscle activation patterns in PD patients. The changes in the muscle activation patterns can be observed with EMG, and the parameters calculated from the signals differ between optimal and non-optimal settings of DBS. This provides a possibility for using the EMG-based measurement to aid the clinicians to adjust the DBS.

Influence of Viscoelasticity on Dynamic Fatiguing Behavior of Muscle Using Myotonometry and Surface Electromyography Measurements

In this work, an attempt has been made to analyse the influence of tissue viscoelasticity on the fatiguing behaviour of skeletal muscle. For this purpose, myotonometry and surface electromyography (sEMG) signals are recorded from the biceps brachii muscle of adult volunteers. Viscoelastic characterization of muscle is carried out using two parameters, namely Dynamic Stiffness (DS) and Relaxation Time (RT) which are computed from the myotonometry signal. Fatiguing contraction is characterized using Time to Task Failure (TTF) and Mean Absolute Value (MAV) extracted from the surface electromyography signal. Linear regression is performed to find the association between myotonometric parameters and TTF. Results show that the TTF values are comparable between both hands, but the values are higher in the dominant hand. Linear relationship between myotonometric parameters and TTF is observed with adjusted R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> > 30% for the dominant hand, and adjusted R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> > 40% for the non-dominant hand. Further, there is variation in the myotonometric parameters between non-fatigue and fatigue states. Similarly, MAV is also noted to increase from non-fatigue to fatigue state. Percentage variation of RT from non-fatigue to fatigue is linearly correlated with average MAV values. The results indicate that viscoelastic properties of muscle along with myoelectrical features can provide better characterization of fatiguing contraction in skeletal muscle, and could be helpful in the domain of sports medicine and rehabilitative design.

Study on Lifting Up and Unloading Work Support with Ankle Foot Orthotics Using Carbon Fiber Composite Material

To prevent back pain during load lifting, assist suits have been developed to reduce physical load by assisting human motion. There are two methods of lifting heavy objects: the stoop method and the squat method. Assistive suits to facilitate the squat method, which reduces the burden on the lower back, have not yet been put to practical use. Therefore, there is a need to develop assistive suits that are lightweight and do not require power. In this study, we developed a short leg orthosis using a leaf spring made of carbon fiber reinforced plastic (CFRP), and conducted lifting and unloading experiments of heavy objects while wearing the orthosis. We then investigated the work support effects of wearing the orthosis based on measurements of lower limb joint power using a three-dimensional motion analysis system and surface electromyography measurements. The results showed that joint angles and power at the ankle and knee joints during lifting was reduced, and joint angles at the ankle and knee joints and power at the knee joint during unloading was reduced by using the orthosis. In both lifting up and unloading, muscle use of the rectus femoris and gastrocnemius muscles decreased, while spinal muscles showed an increasing trend. In addition, muscle synergy analysis revealed two muscle synergies in both lifting up and unloading, indicating that wearing the orthosis reduced lower limb strain during lifting up, and reduced lower back and lower limb strain during unloading and standing up.

Torque Estimation of Knee Flexion and Extension Movements From a Mechanomyogram of the Femoral Muscle.

A mechanomyogram is a visualization of the mechanical signal from the surface of a muscle when the muscle is contracted. The setup of the mechanomyography (MMG) measurement is simpler than the setup for surface electromyography (sEMG) measurement and is less affected by sweating. However, torque estimation based on a mechanomyogram involves significant noise, which is an important issue. Therefore, we propose a regression analysis method to estimate the torque of the knee joint during voluntary movement based on the MMG signal. The proposed method differs from conventional methods because it integrates the MMG sensor responses at four locations: anterior, posterior, and medial/lateral just above the main operating muscle. This method focuses on the acceleration response characteristics, which change slightly depending on the location of the MMG sensor. Support vector regression was performed on the root mean square (RMS) of the MMG signals, which were processed by a low-pass filter. Two-channel estimation with an increased number of MMG sensors for the leading and antagonist muscles improved the conventional method, and four-channel estimation with medial and lateral sensors further improved the performance. These results show that the estimation performance of the proposed method does not significantly differ from that of the surface electromyogram.

Hardware Implementation for Lower Limb Surface EMG Measurement and Analysis Using Explainable AI for Activity Recognition

Electromyography (EMG) signals are gaining popularity for several biomedical applications, including pattern recognition, disease detection, human-machine interfaces, medical image processing, and robotic limb or exoskeleton fabrication. In this study, a two-channel data acquisition system for measuring EMG signals is proposed for human lower limb activity recognition. Five leg activities have been accomplished to measure EMG signals from two lower limb muscles to validate the developed hardware. Five subjects (3 males and 2 females) were chosen to acquire EMG signals during these activities. The raw EMG signal was first denoised using a hybrid of Wavelet Decomposition with Ensemble Empirical Mode Decomposition (WD-EEMD) approach to classify the recorded EMG dataset. Then, eight time-domain features were extracted using the overlapping windowing technique. An investigation into the comparative effectiveness of several classifiers is presented, although it was hard to distinguish how the classifiers predicted the activities. Having a trustworthy explanation for the outcomes of these classifiers would be quite beneficial overall. An approach known as Explainable Artificial Intelligence (XAI) was introduced to produce trustworthy predictive modelling results and applied the XAI technique known as Local Interpretable Model-Agnostic Explanations (LIME) to a straightforward human interpretation. LIME investigates how extracted features are anticipated and which features are most responsible for each action. The accuracy of the Extra Tree Classifier gives the highest accuracy of the other studied algorithms for identifying different human lower limb activities from sEMG signals.

An adjoint approach to identification in electromyography: modeling and first order optimality conditions

In medical treatment it can be necessary to know the position of a motor unit in a muscle. Recent advances in high-density surface electromyography (EMG) measurement have opened the possibility of extracting information about single motor units. We present a mathematical approach to identify these motor units. On the base of an electrostatic forward model, we introduce an adjoint approach to efficiently simulate a surface EMG measurement and an optimal control approach to identify these motor units. We show basic results on existence of solutions and first-order optimality conditions.

Transcutaneous Auricular Vagus Nerve Stimulation (tAVNS) Delivered During Upper Limb Interactive Robotic Training Demonstrates Novel Antagonist Control for Reaching Movements Following Stroke.

Implanted vagus nerve stimulation (VNS) delivered concurrently with upper limb rehabilitation has been shown to improve arm function after stroke. Transcutaneous auricular VNS (taVNS) offers a non-invasive alternative to implanted VNS and may provide similar therapeutic benefit. There is much discussion about the optimal approach for combining VNS and physical therapy, as such we sought to determine whether taVNS administered during robotic training, specifically delivered during the premotor planning stage for arm extension movements, would confer additional motor improvement in patients with chronic stroke. Thirty-six patients with chronic, moderate-severe upper limb hemiparesis (>6 months; mean Upper Extremity Fugl-Meyer score = 25 ± 2, range 13–48), were randomized to receive 9 sessions (1 h in length, 3x/week for 3 weeks) of active (N = 18) or sham (N = 18) taVNS (500 ms bursts, frequency 30 Hz, pulse width 0.3 ms, max intensity 5 mA, ∼250 stimulated movements per session) delivered during robotic training. taVNS was triggered by the onset of a visual cue prior to center-out arm extension movements. Clinical assessments and surface electromyography (sEMG) measures of the biceps and triceps brachii were collected during separate test sessions. Significant motor improvements were measured for both the active and sham taVNS groups, and these improvements were robust at 3 month follow-up. Compared to the sham group, the active taVNS group showed a significant reduction in spasticity of the wrist and hand at discharge (Modified Tardieu Scale; taVNS = –8.94% vs. sham = + 2.97%, p < 0.05). The EMG results also demonstrated significantly increased variance for the bicep peak sEMG amplitude during extension for the active taVNS group compared to the sham group at discharge (active = 26.29% MVC ± 3.89, sham = 10.63% MVC ± 3.10, mean absolute change admission to discharge, p < 0.01), and at 3-month follow-up, the bicep peak sEMG amplitude was significantly reduced in the active taVNS group (P < 0.05). Thus, robot training improved the motor capacity of both groups, and taVNS, decreased spasticity. taVNS administered during premotor planning of movement may play a role in improving coordinated activation of the agonist-antagonist upper arm muscle groups by mitigating spasticity and increasing motor control following stroke.Clinical Trial Registration: www.ClinicalTrials.gov, identifier (NCT03592745).

Combining Unsupervised Muscle Co-Contraction Estimation With Bio-Feedback Allows Augmented Kinesthetic Teaching

Nowadays, an increasingly diversification of products and production lines would largely benefit from intuitive and multimodal robot teaching strategies. The present article proposes an augmented kinesthetic teaching system, which is based on surface electromyographic (sEMG) measurements from the operator forearm. Specifically, sEMG signals are used for minimal-training unsupervised estimation of forearm's muscles co-contraction level. In this way, also exploiting a vibrotactile bio-feedback, we evaluate the ability of operators in stiffening their hand - during kinesthetic teaching - in order to modulate the estimated level of muscle co-contraction to (i) match target levels and (ii) command the opening/closing of a gripper, i.e. in exploiting their sEMG signals for effective augmented robot kinesthetic teaching tasks. Experiments were carried out involving ten subjects in two different kind of experimental sessions, in order to test both co-contraction modulation abilities, and actual usage of the co-contraction for programming robot functionalities during kinesthetic teaching. The obtained results provide positive outcomes on the intuitiveness and effectiveness of the proposed system and approach, paving the way to a new generation of advanced teaching by demonstration interfaces.

Muscle Activation in Specific Regions of the Trapezius During Modified Kendall Manual Muscle Tests.

Manual muscle tests (MMTs) are often used when assessing shoulder injuries. For the trapezius, individual MMTs are used to selectively test the upper trapezius region (UTR), middle trapezius region (MTR), and lower trapezius region (LTR). The MMTs for each region are assumed to preferentially recruit the corresponding muscle fibers and produce a maximal contraction; however, whether this is true is unknown. To determine if maximal voluntary isometric contractions (MVICs) for the upper trapezius (UT-MVIC), middle trapezius (MT-MVIC), and lower trapezius (LT-MVIC), adapted from the Kendall MMTs, recruited the corresponding trapezius regions. Crossover study. Laboratory. A total of young, healthy individuals (10 men, 9 women, 1 not listed; age = 23.9 ± 1.7 years, height = 171.4 ± 9.6 cm, mass = 75.7 ± 11.6 kg). Participants performed 3 repetitions of each MVIC. High-density surface electromyography measurements were collected from the UTR, MTR, and LTR. Root mean square (excitation) of the UTR, MTR, and LTR. We observed an increase in UTR excitation during the LT-MVIC compared with the UT-MVIC (P = .016) and MT-MVIC (P < .001). The MTR excitation increased during the MT-MVIC (P = .001) and the LT-MVIC (P < .001) compared with the UT-MVIC. We also noted an increase in MTR excitation during the LT-MVIC compared with the MT-MVIC (P < .001). The LTR excitation increased during the MT-MVIC and LT-MVIC (P values < .001) compared with the UT-MVIC. The UT-MVIC and MT-MVIC did not necessarily recruit the corresponding trapezius regions more than the other MVICs did. Rather, the LT-MVIC appeared to produce the greatest excitation of all trapezius regions. Additional research is needed; however, clinicians should be aware that maximal contractions may not always recruit the desired muscle region.

Test-Retest Reliability of Surface Electromyographic Measurements in Athletes With Anterior Cruciate Ligament Reconstruction: A Voluntary Response Index Analysis

Test-Retest Reliability of Surface Electromyographic Measurements in Athletes With Anterior Cruciate Ligament Reconstruction: A Voluntary Response Index Analysis

The Reliability of Pelvic Floor Muscle Bioelectrical Activity (sEMG) Assessment Using a Multi-Activity Measurement Protocol in Young Women.

The aim of the study was to determine the between-trial and between-day reliability of the Glazer protocol and our multi-activity surface electromyography (sEMG) measurement protocol for pelvic floor muscle (PFM) evaluation. The bioelectrical activity of PFM was collected using an endovaginal electrode in 30 young, Caucasian, nulliparous women (age 22–27, 168.6 ± 5.1 cm, 57.1 ± 11.8 kg). The between-trial and between-day reliability of the original Glazer protocol and the new multi-activity sEMG protocol were assessed during the following phases: pre-baseline rest, phasic (flick) contractions, tonic contractions, endurance contraction, and post-baseline rest. The Glazer protocol was characterized by poor and moderate measurement reliability. The time-domain parameters for the rise and fall of the signal amplitude and median frequency showed poor between-trial and between-day reliability. The mean and peak amplitudes indicated mainly good between-trial and moderate between-days reliability. Our protocol showed moderate to excellent reliability of both time-domain and quantitative parameters of muscle recruitment. In our protocol, the frequency-domain parameters describing muscle fatigue demonstrated much higher reliability than in the case of the Glazer protocol. The most important information obtained in this study was the significant improvement of diagnostic validity in PFM bioelectrical activity evaluation. The higher reliability of our sEMG protocol compared to original Glazer protocol allowed us to suggest that protocol modifications and changes in sEMG signal processing methods were effective in the improvement of PFM assessment quality. The new parameters calculated from the sEMG signal proposed in our sEMG protocol allowed us to obtain additional clinically important information about PFM dysfunctions regarding specific deficits of muscle contraction such as decrease in muscle strength; endurance or coordination related to, e.g., stress urinary incontinence; or pelvic floor muscle imbalance after childbirth.

A Low-Profile Vacuum Actuator (LPVAc) With Integrated Inductive Displacement Sensing for a Novel Sit-to-Stand Assist Exosuit

Muscle weakness owing to stroke, spinal cord injuries, or aging can make a person’s life sedentary, temporarily as well as permanently. Such persons need to be motivated to break their sedentary postures and attempt independent motion. A key motivator in this aspect is the ability to easily transition from seated to standing posture. If this sit-to-stand transition (STSt) is easy, it will encourage further mobility. A soft wearable device that can assist the STSt, would fill this need perfectly. Such a device should be able to seamlessly assist during STSt and be unobtrusive during sitting. A major limitation that is currently holding back the development of soft exosuits in STSt-assist is the lack of low-profile soft actuators with high strain rate and force-to-weight ratio. Hence, we propose a novel low-profile vacuum actuator (LPVAc) with an integrated inductive displacement sensor that, can be rapidly fabricated, is lightweight (14g), and can provide high strain (65%) and a high force-to-weight ratio (285 times self-weight). The proposed actuator comprises a low-profile spring encased within a low-density polyethylene film with rapid vacuum actuation and passive quick return. The proposed inductive sensor has a sensitivity of $0.0022~\mu H/mm$ and the hysteresis is below 1.5% with an overall absolute average error percentage of 5.24%. The performance of the proposed integrated sensor in displacement control of the LPVAc is experimentally evaluated. The proposed actuator is integrated into a novel mono-articular STSt-assist exosuit for preliminary testing. Surface electromyography measurements of the gluteus maximus muscles during STSt indicate a mean muscle activity reduction of 45%. This supports the potential use of the proposed actuator in STSt-assist.

Test-Retest Reliability of Surface Electromyographic Measurements in Athletes With Anterior Cruciate Ligament Reconstruction: A Voluntary Response Index Analysis

Introduction: Voluntary Response Index (VRI) is used as a measure of motor control to study abnormalities of voluntary movements. This study aimed to evaluate the reliability of voluntary response index analysis in subjects with Anterior Cruciate Ligament Reconstruction (ACLR).Materials and Methods: Using surface electromyography, the VRI components of both groups of 15 ACLR and 15 healthy controls were assessed during the functional task (sit-stand-sit). The outcome variables of VRI included the magnitude and similarity index.Results: In sit to stand phase, high reliability was found (ICC=0.80-0.89) for the magnitude and similarity index in both groups. In the standing phase, high to very high reliability was found for the magnitude and similarity index in both groups (ICC=0.75-0.91). In stand to sit phase, high to very high reliability was found (ICC=0.78-0.92) for the magnitude and similarity index in both groups.Conclusion: Surface electromyographic measurements of VRI analysis demonstrated high to very high reliability in athletes with ACLR during the functional task (sit-stand-sit). The results of the current study showed that the VRI analysis in athletes after ACLR was a reliable method and can be used to evaluate motor control before and after ligament injury in these patients.

Evaluation of the Biomechanical Parameters of Human-Wheelchair Systems during Ramp Climbing with the Use of a Manual Wheelchair with Anti-Rollback Devices

Purpose: The main purpose of the research conducted was the analysis of kinematic and biomechanical parameters measured during manual wheelchair ramp-climbing with the use of the anti-rollback system and the comparison of the values tested with the manual wheelchair climbing the same ramp but without any modifications. The paper presents a quantitative assessment relating to the qualitative research of the anti-rollback system performed by another research team. Method and materials: The article presents the measurement results of the wheelchair motion kinematics and the activity of four upper limb muscles for eight subjects climbing a 4.58° ramp. Each subject propelled the wheelchair both with and without the anti-rollback system. The kinematic parameters were measured by means of two incremental encoders with the resolution of 500 impulses per single revolution of the measurement wheel. Whereas, the muscle activity was measured by means of surface electromyography with the use of Noraxon Mini DTS apparatus equipped with four measurement channels. Results: The surface electromyography measurement indicated an increase in the muscle activity for all four muscles, during the use of the anti-rollback system. The increase was: 18.56% for deltoid muscle anterior, 12.37% for deltoid muscle posteriori, 13.0% for triceps brachii, and 15.44% for extensor carpi radialis longus. As far as the kinematics analysis is concerned, a decrease in the measured kinematic parameters was observed in most participants. The medium velocity of the propelling cycle decreased by 26%. The ratio of the generated power and the loss power in a single propelling cycle λ had decreased by 18%. The least decrease was recorded for the measurement of mechanical energy E and the propelling cycle duration time. For the total mechanical energy, the decrease level was 3%, and for the propelling cycle duration it was 1%. The research carried out did not demonstrate any impact of the anti-rollback system use on the push phase share in the entire propelling cycle.

A SYSTEMATIC REVIEW AND META-ANALYSIS OF COMMON THERAPEUTIC EXERCISES THAT GENERATE HIGHEST MUSCLE ACTIVITY IN THE GLUTEUS MEDIUS AND GLUTEUS MINIMUS SEGMENTS.

The gluteus medius (GMed) and gluteus minimus (GMin) muscle segments demonstrate different responses to pathology and ageing, hence it is important in rehabilitation that prescribed therapeutic exercises can effectively target the individual segments with adequate exercise intensity for strengthening. The purpose of this systematic review was to evaluate whether common therapeutic exercises generate at least high ( > 40% maximum voluntary isometric contraction (MVIC)) electromyographic (EMG) activity in the GMed (anterior, middle and posterior) and GMin (anterior and posterior) segments. Seven databases (MEDLINE, EMBASE, CINAHL, AusSPORT, PEDro, SPORTdiscus and Cochrane Library) were searched from inception to May 2018 for terms relating to gluteal muscle, exercise, and EMG. The search yielded 6918 records with 56 suitable for inclusion. Quality assessment, data extraction and data analysis were then undertaken with exercise data pooled into a meta-analysis where two or more studies were available for an exercise and muscle segment. For the GMed, different variations of the hip hitch/ pelvic drop exercise generated at least high activity in all segments. The dip test, and isometric standing hip abduction are other options to target the anterior GMed segment, while isometric standing hip abduction can be used for the posterior GMed segment. For the middle GMed segment, the single leg bridge; side-lying hip abduction with hip internal rotation; lateral step-up; standing hip abduction on stance or swing leg with added resistance; and resisted side-step were the best options for generating at least high activity. Standing isometric hip abduction and different variations of the hip hitch/ pelvic drop exercise generated at least high activity in all GMin segments, while side-lying hip abduction, the dip test, single leg bridge and single leg squat can also be used for targeting the posterior GMin segment. The findings from this review provide the clinician with confidence in exercise prescription for targeting individual GMed and GMin segments for potential strengthening following injury or ageing. Level 1. Previous reviews on GMed exercises have been based on single electrode, surface EMG measures at middle GMed segment. It is not known whether these exercises effectively target the other segments of GMed or the GMin at a sufficient intensity for strengthening. This review provides the clinician with confidence in exercise prescription of common therapeutic exercises to effectively target individual GMed and GMin segments for potential strengthening.

The Effect of ICA and Non-negative Matrix Factorization Analysis for EMG Signals Recorded From Multi-Channel EMG Sensors.

Surface electromyography (EMG) measurements are affected by various noises such as power source and movement artifacts and adjacent muscle activities. Hardware solutions have been found that use multi-channel EMG signal to attenuate noise signals related to sensor positions. However, studies addressing the overcoming of crosstalk from EMG and the division of overlaid superficial and deep muscles are scarce. In this study, two signal decompositions—independent component analysis and non-negative matrix factorization—were used to create a low-dimensional input signal that divides noise, surface muscles, and deep muscles and utilizes them for movement classification based on direction. In the case of index finger movement, it was confirmed that the proposed decomposition method improved the classification performance with the least input dimensions. These results suggest a new method to analyze more dexterous movements of the hand by separating superficial and deep muscles in the future using multi-channel EMG signals.

Quantification of abdominal and back muscles forces: calibration for the Sorensen test

In the human body, assessing muscle forces can be done using either experimental or mathematical approaches. The former often relies on the use of surface electromyography (EMG) measurements, altho...