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Journal of Electromyography and Kinesiology

Maurice Mohr, Kristin Lorenzen, Luz Palacios-Derflingher, Carolyn Emery, Benno M Nigg
Despite the frequent use of the electromyography-based muscle co-contraction index (CCI) to examine muscular control of the knee joint in young adults with and without knee injury history, the reliability of the CCI in this population is unknown. The purpose of this study was to quantify within-day and between-day reliability of the knee muscle CCI during gait in young adults with and without knee injury history. Twenty young adults (10 males, 10 females) with and without history of intra-articular knee injury performed repeated gait analyses on two different days...
November 6, 2017: Journal of Electromyography and Kinesiology
Silvija Angelova, Simeon Ribagin, Rositsa Raikova, Ivanka Veneva
After a stroke, motor units stop working properly and large, fast-twitch units are more frequently affected. Their impaired functions can be investigated during dynamic tasks using electromyographic (EMG) signal analysis. The aim of this paper is to investigate changes in the parameters of the power/frequency function during elbow flexion between affected, non-affected, and healthy muscles. Fifteen healthy subjects and ten stroke survivors participated in the experiments. Electromyographic data from 6 muscles of the upper limbs during elbow flexion were filtered and normalized to the amplitudes of EMG signals during maximal isometric tasks...
October 31, 2017: Journal of Electromyography and Kinesiology
Tyson A C Beach, Tatjana Stankovic, Danielle R Carnegie, Rachel Micay, David M Frost
"Use your legs" is commonly perceived as sound advice to prevent lifting-related low-back pain and injuries, but there is limited evidence that this directive attenuates the concomitant biomechanical risk factors. Body segment kinematic data were collected from 12 men and 12 women who performed a laboratory lifting/lowering task after being provided with different verbal instructions. The main finding was that instructing participants to lift "without rounding your lower back" had a greater effect on the amount of spine flexion they exhibited when lifting/lowering than instructing them to lift "with your legs instead of your back" and "bend your knees and hips"...
October 31, 2017: Journal of Electromyography and Kinesiology
Sung-Hoon Jung, Ui-Jae Hwang, Jun-Hee Kim, Gyeong-Tae Gwak, Oh-Yun Kwon
Increased activity of the serratus anterior (SA) muscle combined with decreased activity of the pectoralis major (PM) muscle during scapular protraction exercise is a widely used method for selective strengthening of the former muscle. However, the role played by the PM during maximal scapular protraction remains unclear. The objective of our study was to investigate the effects of horizontal shoulder abduction (decreasing PM activity) and adduction (increasing activity) on the strength and activity of the scapular protractors (the SA and PM) during maximal protraction...
October 27, 2017: Journal of Electromyography and Kinesiology
Ryoichi Ema, Taku Wakahara, Yasuo Kawakami
This study tested the hypothesis that the effect of hip joint angle on concentric knee extension torque depends on knee joint angle during a single knee extension task. Twelve men performed concentric knee extensions in fully extended and 80° flexed hip positions with maximal effort. The angular velocities were set at 30° s(-1) and 180° s(-1). The peak torque and torques attained at 30°, 50°, 70° and 90° (anatomical position = 0°) of the knee joint were compared between the two hip positions...
October 26, 2017: Journal of Electromyography and Kinesiology
V J M M Festen-Schrier, P C Amadio
Carpal Tunnel Syndrome (CTS) is the most common surgically treated problem in the hand. Aside from the neuropathy itself, the most common findings are fibrosis of the subsynovial connective tissue (SSCT) and increased intra carpal tunnel pressure. Normally, the SSCT is a multilayer tissue interspersed among the carpal tendons and nerve. As the tendons move, successive SSCT layers are recruited, forming a gliding unit and providing a limit to differential movement. Exceeding this limit, damages the SSCT as has been shown in both cadavers and animal models...
October 24, 2017: Journal of Electromyography and Kinesiology
Michael F Knox, Lucy S Chipchase, Siobhan M Schabrun, Paul W M Marshall
The purpose of this study was to determine if 8 weeks of exercise affects motor control in people with chronic low back pain (CLBP), measured by anticipatory (APAs) and compensatory postural adjustments (CPAs). APAs and CPAs were measured prior to and following 8 weeks in two groups of people with CLBP: an exercise group (n=12) who attended three exercise sessions per week for 8 weeks; and a non-exercise control group (n=12) who were advised to continue their usual activities for the duration of the study. APAs and CPAs were recorded during unilateral arm flexion, bilaterally from rectus abdominis (RA), transverse abdominis/internal oblique (TA/IO), and erector spinae (ES) via surface electromyography...
October 20, 2017: Journal of Electromyography and Kinesiology
C L Liu, Y N Feng, H Q Zhang, Y P Li, Y Zhu, Z J Zhang
BACKGROUND: Increasing stiffness in the upper trapezius muscle may contribute to imbalance of scapular motion, and result in shoulder and neck discomfort during shoulder flexion. Therefore, it is essential to quantify upper trapezius stiffness in various shoulder positions in order to aid in the prevention of these disorders and to optimize rehabilitation. OBJECTIVES: The objectives of the present study were to examine the intra and inter-tester reliability of MyotonPRO device in measuring upper trapezius stiffness and its ability to determine changes in stiffness during shoulder flexion...
October 19, 2017: Journal of Electromyography and Kinesiology
Deniz Simsek
The purpose of this study was to determine the effects of static whole-body vibration (WBV) on the Electromyograhic (EMG) responses of leg muscles, which are fatigue-resistant in different manner. The study population was divided into two groups according to the values obtained by the Fatigue Index [Group I: Less Fatigue Resistant (LFR), n=11; Group II: More Fatigue Resistant (MFR), n=11]. The repeated electromyographic (EMG) activities of four leg muscles were analyzed the following determinants: (1) frequency (30 Hz, 35 Hz and 40 Hz); (2) stance position (static squat position); (3) amplitude (2 mm and 4 mm) and (4) knee flexion angle (120°), (5) vertical vibration platform...
October 19, 2017: Journal of Electromyography and Kinesiology
Yuichi Nishikawa, Kohei Watanabe, Tetsuya Takahashi, Naoya Orita, Hiroaki Kimura, Masayasu Matsumoto, Hirofumi Maruyama
Parkinson's disease (PD) related decreases in muscle strength may result from both central and peripheral factors. However, the effect of PD on the neuromuscular system, such as motor unit activation properties, remains unclear. The purpose of the present study was to compare the spatial distribution pattern of electromyographic activity during sustained contractions in healthy subjects and PD patients. Twenty-five female PD patients and 25 healthy age-matched female control subjects performed ramp submaximal contractions during an isometric knee extension from 20% to 80% of the maximal voluntary contraction (MVC)...
October 19, 2017: Journal of Electromyography and Kinesiology
Armin Paravlić, Damir Zubac, Boštjan Šimunič
Electromechanical efficiency (EME) of skeletal muscle represents the dissociation between the mechanomyographic (MMG) to electromyographic (EMG) amplitudes and was commonly used in clinical settings (e.g. muscle disease, atrophy, rehabilitation). However, due to lower reliability and of both MMG and EMG as well as lower validity of MMG we aimed to establish the intra-day, inter-day and inter-rater reliability of modified EME. Reliability was examined for maximal soleus twitch amplitudes of tensiomyographic (Dm) and M-wave (Mptp) responses, as well as for EME derived as Dm/Mptp, in 18 healthy participants (55% males; 30...
October 19, 2017: Journal of Electromyography and Kinesiology
Francesco Negro, Claudio Orizio
The characteristics of motor unit force twitch profiles provide important information for the understanding of the muscle force generation. The twitch force is commonly estimated with the spike-triggered averaging technique, which, despite the many limitations, has been important for clarifying central issues in force generation. In this study, we propose a new technique for the estimation of the average twitch profile of populations of motor units with uniform contractile properties. The method encompasses a model-based deconvolution of the force signal using the identified discharge times of a population of motor units...
October 18, 2017: Journal of Electromyography and Kinesiology
Huub Maas, H E J Dirkjan Veeger, Dick F Stegeman
No abstract text is available yet for this article.
October 16, 2017: Journal of Electromyography and Kinesiology
T-J Grewal, A C Cudlip, C R Dickerson
Altered scapular motions premeditate shoulder impingement and other musculoskeletal disorders. Divergent experimental conditions in previous research precludes rigorous comparisons of non-invasive scapular tracking techniques. This study evaluated scapular orientation measurement methods across an expanded range of humeral postures. Scapular medial/lateral rotation, anterior/posterior tilt and protraction/retraction was measured using an acromion marker cluster (AMC), a scapular locator, and a reference stylus...
October 12, 2017: Journal of Electromyography and Kinesiology
Marzieh M Ardestani, Philip Malloy, Denis Nam, Aaron G Rosenberg, Markus A Wimmer
Nearly 20% of patients who have undergone total knee arthroplasty (TKA) report persistent poor knee function. This study explores the idea that, despite similar knee joint biomechanics, the neuro-motor synergies may be different between high-functional and low-functional TKA patients. We hypothesized that (1) high-functional TKA recruit a more complex neuro-motor synergy pattern compared to low-functional TKA and (2) high-functional TKA patients demonstrate more stride-to-stride variability (flexibility) in their synergies...
September 28, 2017: Journal of Electromyography and Kinesiology
Lucio Marinelli, Antonio Currà, Carlo Trompetto, Elisabetta Capello, Carlo Serrati, Francesco Fattapposta, Elisa Pelosin, Chetan Phadke, Claire Aymard, Luca Puce, Franco Molteni, Giovanni Abbruzzese, Fabio Bandini
BACKGROUND: Spasticity and spastic dystonia are two separate phenomena of the upper motor neuron syndrome. Spasticity is clinically defined by velocity-dependent hypertonia and tendon jerk hyperreflexia due to the hyper-excitability of the stretch reflex. Spastic dystonia is the inability to relax a muscle leading to a spontaneous tonic contraction. Both spasticity and spastic dystonia are present in patients who are at rest; however, only patients with spasticity are actually able to kept their muscles relaxed prior to muscle stretch...
September 27, 2017: Journal of Electromyography and Kinesiology
Yuta Koshino, Masanori Yamanaka, Yuya Ezawa, Takumi Okunuki, Tomoya Ishida, Mina Samukawa, Harukazu Tohyama
The objective of the current study was to investigate the kinematic relationships between the rearfoot and hip/knee joint during walking and single-leg landing. Kinematics of the rearfoot relative to the shank, knee and hip joints during walking and single-leg landing were analyzed in 22 healthy university students. Kinematic relationships between two types of angular data were assessed by zero-lag cross-correlation coefficients and coupling angles, and were compared between joints and between tasks. During walking, rearfoot eversion/inversion and external/internal rotation were strongly correlated with hip adduction/abduction (R=0...
September 22, 2017: Journal of Electromyography and Kinesiology
Paul Ansdell, Kevin Thomas, Glyn Howatson, Sandra Hunter, Stuart Goodall
Females are less fatigable than males during isometric contractions across various muscles and intensities. However, sex differences in knee-extensor fatigability remain relatively unexplored. PURPOSE: To determine the sex difference in performance fatigability for intermittent, isometric contractions of the knee-extensor muscles. METHODS: Eighteen participants (10 males, 8 females) performed intermittent, isometric, knee-extensor contractions at 30% of their maximal voluntary force (MVC) for 30min and in a separate session at 50% MVC until task-failure...
September 21, 2017: Journal of Electromyography and Kinesiology
Alireza Sedighi, Maury A Nussbaum
Existing research indicates that repetitive motions are strongly correlated with the development of work-related musculoskeletal disorders (WMSDs). Resulting from the redundant degrees-of-freedom in the human body, there are variations in motions that occur while performing a repetitive task. These variations are termed motor variability (MV), and may be beneficial for reducing WMSD risks. To better understand the potential role of MV in preventing injury risk, we evaluated the effects of fatigue on MV using data collected during a lab-based prolonged, repetitive lifting/lowering task...
September 15, 2017: Journal of Electromyography and Kinesiology
Luca Zoffoli, Massimiliano Ditroilo, Ario Federici, Francesco Lucertini
This study used surface electromyography (EMG) to investigate the regions and patterns of activity of the external oblique (EO), erector spinae longissimus (ES), multifidus (MU) and rectus abdominis (RA) muscles during walking (W) and pole walking (PW) performed at different speeds and grades. Eighteen healthy adults undertook W and PW on a motorized treadmill at 60% and 100% of their walk-to-run preferred transition speed at 0% and 7% treadmill grade. The Teager-Kaiser energy operator was employed to improve the muscle activity detection and statistical non-parametric mapping based on paired t-tests was used to highlight statistical differences in the EMG patterns corresponding to different trials...
September 9, 2017: Journal of Electromyography and Kinesiology
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