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Journal of Electromyography and Kinesiology

M Rinaldi, C D'Anna, M Schmid, S Conforto
Muscle co-activation is the mechanism that regulates simultaneous activity of agonist and antagonist muscles crossing the same joint. During functional movements, robust measurement techniques are required for an accurate determination of muscle co-activation, since various environmental and processing factors in the surface electromyography (sEMG) measurement process might influence the estimation of linear envelope profiles, and therefore the outcome of co-activation evaluated from the signal envelope. The aim of this study is to verify the performance of the co-activation indexes introduced in six different techniques used to assess muscle co-activation...
October 21, 2018: Journal of Electromyography and Kinesiology
Andreia S P Sousa
PURPOSE: This study aims to evaluate bilateral ankle antagonist co-activation during compensatory postural responses, including short latency responses (SLR) and medium latency responses (MLR), in response to a unilateral sudden ankle inversion in subjects with chronic ankle instability (CAI). METHODS: Twenty-four participants with CAI and 20 controls participated in the present study. Bilateral eletromyography of peroneus longus (PL), peroneus brevis (PB), tibialis anterior (TA) and soleus (SOL) muscles was collected during a unilateral sudden inversion perturbation (30°) to assess antagonist co-activation of SOL/TA and TA/P pairs during SLR and MLR in both support and perturbed positions...
October 15, 2018: Journal of Electromyography and Kinesiology
Liang He, Pierre A Mathieu
With modern upper limb myoelectric prostheses, many movements can be produced when many control signals are available. Some of them could originate from the multifunctional biceps brachii which appears to be composed of up to six individually innervated compartments. Given its compartmental nature, this muscle behaves as if composed of many individual muscles acting in synergy to achieve a given motor task. Through an appropriate synergy model, its EMG signals could thus be used to produce some of the many control signals required with modern upper limb myoelectric prostheses...
October 13, 2018: Journal of Electromyography and Kinesiology
Maria Knikou, Lynda M Murray
The objective of this study was to establish neural interactions between transspinal evoked potentials (TEPs) and muscle spindle group Ia afferents in healthy humans. Soleus H-reflexes were assessed following transspinal stimulation at conditioning-test (C-T) intervals that ranged from negative to positive 100 ms. TEPs were recorded from the right and left ankle/knee flexor and extensor muscles, and their amplitude was assessed following stimulation of soleus muscle spindle group Ia afferents at similar C-T intervals...
October 9, 2018: Journal of Electromyography and Kinesiology
Xun Yang, Yuzhou Liu, Xin Zhao, Jie Lao
In this study, we investigated the electrophysiologic recovery of the abductor pollicis brevis (APB) muscle after contralateral seventh cervical (cC7) nerve transfer for the treatment of global brachial plexus avulsion (GBPA). We retrospectively analyzed the electromyography records of 95 patients with GBPA, comprising 81 men and 14 women, focusing on the motor unit potential (MUP) recovery of the APB. All patients underwent cC7-median nerve (MN) transfer. The cC7 nerve was transferred to the MN alone in 58 patients (One-Nerve Group), whereas 37 patients underwent cC7 transfer to the MN and another nerve (Two-Nerve Group)...
October 8, 2018: Journal of Electromyography and Kinesiology
Sebastian Roldan-Vasco, Sebastian Restrepo-Agudelo, Yorhagy Valencia-Martinez, Andres Orozco-Duque
Swallowing is a complex process that involves sequential voluntary and involuntary muscle contractions. Malfunctioning of swallowing related muscles could lead to dysphagia. However, there is a lack of standardized and non-invasive methods that support and improve the diagnosis and ambulatory care. This paper presents a classification scheme of two swallowing phases (oral and pharyngeal) based on signals of surface electromyography (sEMG). Eight acquisition channels recorded the EMG activity of 47 healthy subjects while they swallowed water, yogurt and saliva...
October 6, 2018: Journal of Electromyography and Kinesiology
Tim J L Raven, Lise R Lothe, Gunnar Sandbæk, Torsten Eken
Precise electrode placement is essential for obtaining useful electromyographic (EMG) recordings. Our aim was to develop a protocol for computerized-tomography (CT) guided fine-wire (FW) electrode placement that permits confirmation of the final electrode position in the deep posterior cervical multifidus (CM). FW-EMG electrodes were custom-made from three 50-µm diameter Teflon-insulated platinum/iridium wires. The electrodes were inserted bilaterally in the CM in 15 healthy adult subjects through a 45-mm cannula under CT guidance...
October 6, 2018: Journal of Electromyography and Kinesiology
T Varrecchia, M Rinaldi, M Serrao, F Draicchio, C Conte, S Conforto, M Schmid, A Ranavolo
Muscle coactivation is the mechanism that regulates the simultaneous activity of antagonist muscles around the same joint. During walking, muscle joint coactivation varies within the gait cycle according to the functional role of the lower limb joints. In the present study, we used a time-varying multi-muscle coactivation function (TMCf) with the aim of investigating the coactivation of 12 lower limb muscles and its relationship with the gait cycle, gait speed (low, self-selected, and fast), ground reaction force, gait variability, and mechanical energy consumption, and recovery in a sample of 20 healthy subjects...
September 28, 2018: Journal of Electromyography and Kinesiology
Annamaria Otto, Kim Emery, Julie N Côté
Fatigue is a risk factor for the development of work-related musculoskeletal disorders (WMSDs) of the neck/shoulder, and exertion is a state that connects the sensory/affective and physical aspects of fatigue. Relationships between ratings of perceived exertion (RPE) and electromyogram (EMG) signal characteristics have been identified. However, the sex-specific effects on these relationships are unclear and could be affected by personal factors such as skinfold thickness. 28 healthy young adults completed a fatiguing task with the arm held at shoulder height...
September 25, 2018: Journal of Electromyography and Kinesiology
Mina Alizadeh, Gregory G Knapik, William S Marras
The importance of surface-EMG placement for development and interpretation of EMG-assisted biomechanical models is well established. Since MR has become a reliable noninvasive cervical spine musculoskeletal diagnostic tool, this investigation attempted to illustrate the anatomical relationships of individual cervical spine muscles with their paired surface-EMG electrodes. The secondary purpose of this investigation was to provide an MR cross-sectional pictorial and descriptive guideline of the cervical spine musculature...
September 25, 2018: Journal of Electromyography and Kinesiology
Daniel F Feeney, Robyn A Capobianco, Jana R Montgomery, Joseph Morreale, Alena M Grabowski, Roger M Enoka
Walking is often compromised in individuals with low back and hip disorders, such as sacroiliac joint dysfunction (SIJD). The disorder involves reduced coactivation of the gluteus maximus and contralateral latissimus dorsi, which together provide joint stability during walking. The purpose of our study was to compare the kinematics and contributions of selected muscles to identified synergies during walking between healthy individuals and those with SIJD. Six women with unilateral SIJD and six age-matched healthy controls walked on a force-measuring treadmill at 1 m/s while we recorded kinematics and the activity of 16 muscles with surface EMG...
September 22, 2018: Journal of Electromyography and Kinesiology
Jakob L Dideriksen, Francesco Negro
Spike-triggered averaging is a commonly used technique for the estimation of motor unit twitches during voluntary contractions, although the obtained twitch estimates are known to be inaccurate in several conditions. Nevertheless, it is commonly assumed that a careful selection of the triggers may reduce the inaccuracy. This study aimed to analyze the impact of trigger selection criteria and thereby to identify the minimum estimation errors using a computational neuromuscular model. Force signals of five-minute duration were simulated at 10 contraction levels between 1 and 30% of the maximal voluntary contraction level (MVC) for motor unit pools of varying size (100, 300, and 800 motor units)...
September 22, 2018: Journal of Electromyography and Kinesiology
Simon Avrillon, François Hug, Gaël Guilhem
PURPOSE: This study aimed to assess muscle coactivation in quadriceps and hamstring muscles using ultrasound shear wave elastography. METHODS: During maximal voluntary isometric contractions (MVC), both myoelectrical activity and shear modulus of antagonist muscles were measured (i.e., rectus femoris, vastus lateralis and vastus medialis during knee flexions and semitendinosus, semimembranosus and biceps femoris long head during knee extensions). To account for changes induced by inevitable joint rotation during MVC, the shear modulus values were compared to those measured at the same knee angle during a passive cycle...
September 21, 2018: Journal of Electromyography and Kinesiology
Christopher McDowell, Matthew Smyk, Paul S Sung
Compensatory trunk and hip motions following slip perturbations may compromise the control of lumbopelvic movement. However, it is unclear how postural integration of the trunk and hips can be transferred to treadmill-induced slip perturbations in subjects with chronic low back pain (LBP). The purpose of this study was to investigate trunk reaction times and three-dimensional trunk-hip angle changes following a slip perturbation (duration: 0.12 sec, velocity: 1.37 m/sec, displacement: 8.22 cm) with a handheld task between subjects with and without chronic LBP...
September 15, 2018: Journal of Electromyography and Kinesiology
Simone C Gafner, Veronika Hoevel, Ilona M Punt, Stefan Schmid, Stephane Armand, Lara Allet
Diminished hip abductor strength decreases postural control which is a parameter that is associated with an increased risk of ankle sprains. In our study we evaluated the influence of hip abductor fatigue on sagittal plane ankle kinematics and shank muscle activity during a single-leg forward jump. Sagittal ankle plane kinematics are important in ankle sprains but less studied than frontal plane kinematics. Therefore, we evaluated differences in sagittal ankle kinematics (12-camera motion capture system) and lower limb surface electromyographic muscle activity in 20 healthy, recreationally active adults (9 females, 11 males, mean age 30...
September 12, 2018: Journal of Electromyography and Kinesiology
Marija Trajkov, Ivan Cuk, Fadilj Eminovic, Dragana Kljajic, Milivoj Dopsaj
Physical activity, muscle strength and the ability to maintain postural stability (PS) are important for well-being in old age. Therefore, the first aim of this study was to assess the contractile abilities of the hand muscles (CAHM) in physically active (PA) and sedentary (SED) older women. The second aim was to examine the relationship between CAHM and PS indicators in older women. The sample of 75 women (aged 65-86 years), was divided into PA and SED group. Differences in CAHM, namely rate of force development and muscular endurance, were confirmed in favor of PA group, whereas, no differences were found between PA and SED group regarding maximum force...
September 12, 2018: Journal of Electromyography and Kinesiology
David C Kingston, Stacey M Acker
Activation waveforms of vastus intermedius, adductor magnus, and semimembranosus have not been reported for high knee flexion activities such as kneeling or squatting, likely due to the invasive procedures required for their measurement. Their relatively large physiological cross sectional areas would suggest their contributions to knee joint loading could be considerable. Therefore, the purpose of this study was to quantify the activities of these muscles using fine-wire EMG and to assess easy to measure surface sites (vastus lateralis, rectus femoris, vastus medialis, semitendinosus, and biceps femoris) for their potential as proxy measures using <10 %MVC RMS and >0...
September 12, 2018: Journal of Electromyography and Kinesiology
Alister du Rose, Alex Breen, Alan Breen
Muscle strengthening exercises are commonly used in primary care for the treatment of chronic, non-specific low back pain (CNSLBP) as it has been theorised that increased muscle activity contributes to the stabilisation of inter-vertebral motion segments during bending and other spinal movements, however this has never been demonstrated in vivo. This study used contemporaneous quantitative fluoroscopy (QF) and surface electromyography (sEMG) to investigate relationships between continuous inter-vertebral motion variables and muscle electrical activity in the lumbar multifidus (LMU), lumbar and thoracic erector spinae (LES and TES) during standardised lumbar flexion and return in 18 healthy male human subjects...
September 12, 2018: Journal of Electromyography and Kinesiology
Kaja Kastelic, Matej Voglar, Nejc Šarabon
INTRODUCTION: Prolonged sitting is often proposed as a risk factor for low back pain development. The purpose of this study was to evaluate the acute effect of full time office work on sensorimotor trunk functions. METHODS: Seventeen healthy office workers participated in the study. Maximal lumbar flexion range of motion, anticipatory postural adjustments and postural reflex reactions were tested before and after full time office work in a real life environment...
September 11, 2018: Journal of Electromyography and Kinesiology
Elisa S Arch, Sarah Colon, Karin Grävare Silbernagel, Jeremy R Crenshaw
Individuals with plantar flexor weakness often require rehabilitation and/or orthoses, which should be personalized based on level of weakness. While plantar flexor weakness can be measured via peak plantar flexion moment during gait (MGAIT ), motion analysis systems are often not clinically available. Clinical measures, such as the single-leg heel rise (SLHR) test and isometric muscle test, may provide surrogate measures of plantar flexor function during gait. However, it is currently unknown if a relationship(s) exists between such measures...
September 11, 2018: Journal of Electromyography and Kinesiology
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