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Flexion-relaxation ratio in computer workers with and without chronic neck pain
This study evaluated the flexion-relaxation phenomenon (FRP) and flexion-relaxation ratios (FR-ratios) using surface electromyography (sEMG) of the cervical extensor muscles of computer workers with and without chronic neck pain, as well as of healthy subjects who were not computer users. This study comprised 60 subjects 20-45 years of age, of which 20 were computer workers with chronic neck pain (CPG), 20 were computer workers without neck pain (NPG), and 20 were control individuals who do not use computers for work and use them less than 4 h/day for other purposes (CG). (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - January 6, 2016 Category: Neurology Authors: Carina Ferreira Pinheiro, Marina Foresti dos Santos, Thais Cristina Chaves Source Type: research

The translational value of shoulder biomechanics research
The 10th Conference of the International Shoulder Group was held July 13-15 at the University of Waterloo and hosted by Dr. Clark Dickerson of the Kinesiology department there. Over 70 shoulder researchers gathered to discuss current concepts and developments in the area of transdisciplinary shoulder biomechanics. Nearly 50 scientific abstracts were presented over the course of the conference. These were supplemented by two keynote lectures from Ontario leaders in medical research: (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 24, 2015 Category: Neurology Authors: Clark R. Dickerson, Andrea G. Cutti Source Type: research

Micro movements of the upper limb in fibromyalgia: The relation to proprioceptive accuracy and visual feedback
The purpose of this study was to explore the role of visual and proprioceptive feedback in upper limb posture control in fibromyalgia (FM) and to assess the coherence between acceleration measurements of upper limb micro movements and surface electromyography (sEMG) of shoulder muscle activity (upper trapezius and deltoid). Twenty-five female FM patients and 25 age- and sex-matched healthy controls (HCs) performed three precision motor tasks: 1) maintain a steady shoulder abduction angle of 45˚ while receiving visual feedback about upper arm position and supporting external loads (0.5, 1, or 2 kg), 2) maintain the same sh...
Source: Journal of Electromyography and Kinesiology - December 22, 2015 Category: Neurology Authors: Ellen Marie Bardal, Karin Roeleveld, Espen Ihlen, Paul Jarle Mork Source Type: research

Effects of Scapular Upward Rotation Exercises on Alignment of Scapula and Clavicle and Strength of Scapular Upward Rotators in Subjects With Scapular Downward Rotation Syndrome
The purpose of this study was to investigate the effects of a 6–week scapular upward rotation exercise (SURE) on scapular and clavicular alignment and scapular upward rotators strength in subjects with scapular downward rotation syndrome (SDRS). Seventeen volunteer subjects with SDRS were recruited from university populations. The alignment of the scapula and clavicle was measured using radiographic analysis and compared in subjects before and after a 6–week self–SURE program. A hand–held dynamometer was used to measure the strength of the scapular upward rotators. (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 22, 2015 Category: Neurology Authors: Sung-min Ha, Oh-yun Kwon, Chung-hwi Yi, Heon-seock Cynn, Jong-hyuck Weon, Tae-ho Kim Source Type: research

Surface electromyography in animal biomechanics: A systematic review
The study of muscle activity using surface electromyography (sEMG) is commonly used for investigations of the neuromuscular system in man. Although sEMG has faced methodological challenges, considerable technical advances have been made in the last few decades. Similarly, the field of animal biomechanics, including sEMG, has grown despite being confronted with often complex experimental conditions. In human sEMG research, standardised protocols have been developed, however these are lacking in animal sEMG. (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 21, 2015 Category: Neurology Authors: Stephanie Valentin, Rebeka R. Zsoldos Tags: Review Source Type: research

Acute severe male hypo-testosteronemia affects central motor command in humans
To indirectly evaluate the effect of androgens on neuromuscular system in humans we analyzed if an induced short-term hypogonadal state (serum total testosterone-TT (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 19, 2015 Category: Neurology Authors: Felici Francesco, Bazzucchi Ilenia, Sgrò Paolo, Quinzi Federico, Conti Alessandra, Aversa Antonio, Gizzi Leonardo, Mezzullo Marco, Romanelli Francesco, Pasquali Renato, Lenzi Andrea, Di Luigi Luigi Source Type: research

Anticipation of direction and time of perturbation modulates the onset latency of trunk muscle responses during sitting perturbations
The objectives of this study were to identify the responses of trunk muscles to sudden support surface translations and quantify the effects of anticipation of direction and time of perturbation on the trunk neuromuscular responses. Twelve able-bodied individuals participated in the study. Participants were seated on a kneeling chair and support surface translations were applied in the forward and backward directions with and without direction and time of perturbation cues. (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 18, 2015 Category: Neurology Authors: Matija Milosevic, Masahiro Shinya, Kei Masani, Kramay Patel, Kristiina M.V. McConville, Kimitaka Nakazawa, Milos R. Popovic Source Type: research

The surface electromyographic evaluation of the Functional Reach in elderly subjects
This study proposes a comprehensive assessment of myoelectric activity of the main muscles involved in the Functional Reach (FR) test, in 24 elderly subjects. A specific protocol for the surface electromyography (sEMG) signal acquisition during FR-test was developed. Results show that anterior muscles activate following a caudo-cranial order. Tibialis Anterior (TA) is the first to be activated (-18.0±16.3% of the FR-period), together with Rectus Femoris (-10.4±17.9%). Then, Rectus Abdominis (19.7±24.7%) and Sternocleidomastoideus (19.9±15.6%) activate after the FR-start. (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 17, 2015 Category: Neurology Authors: E. Maranesi, S. Fioretti, G.G. Ghetti, R.A. Rabini, L. Burattini, O. Mercante, F. Di Nardo Source Type: research

An Approach for Improving Repeatability and Reliability of Non-negative Matrix Factorization for Muscle Synergy Analysis
The aim of this study was to evaluate non-negative matrix factorization (NMF) and concatenated NMF (CNMF) to analyze and reliably extract muscle synergies. NMF and CNMF were used to extract knee joint muscle synergies from surface EMGs collected during a weight bearing, force matching task. Repeatability and between subject similarity were evaluated for each method using intra-class correlation coefficients (ICCs). High repeatability was found for CNMF (>0.99; 0.99-1.0) compared to NMF (>0.26; range 0.26-0.98). (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 16, 2015 Category: Neurology Authors: Mohammad S. Shourijeh, Teresa E. Flaxman, Daniel L. Benoit Source Type: research

Comparison between the effectiveness of expiration and abdominal bracing maneuvers in maintaining spinal stability following sudden trunk loading
The purpose of this study was to clarify the effectiveness of expiration and abdominal bracing maneuvers in response to sudden trunk loading in healthy subjects. Fifteen healthy male subjects were anteriorly loaded under different experimental conditions. Tests were conducted at rest and while performing each of the stabilization maneuvers (expiration and abdominal bracing) at 15% of the maximal voluntary isometric contraction of the internal oblique muscle. Subjects had no knowledge of the perturbation timing. (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 12, 2015 Category: Neurology Authors: Hiroshi Ishida, Tadanobu Suehiro, Chiharu Kurozumi, Susumu Watanabe Source Type: research

The relationship between dynamic balancing ability and posture-related modulation of the soleus H-reflex
This study examined the relationship between dynamic balancing ability and soleus H-reflex posture-related modulation. (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 11, 2015 Category: Neurology Authors: Yu Kawaishi, Kazuhisa Domen Source Type: research

Correlation between semitendinosus and gracilis tendon cross-sectional area determined using ultrasound, magnetic resonance imaging and intraoperative tendon measurements
The purpose of this study was to examine the correlation in semitendinosus (ST) and gracilis (GT) tendon cross-sectional area (CSA) evaluated directly during anterior cruciate ligament (ACL) surgery and pre-operatively using ultrasound (US) and magnetic resonance imaging (MRI). A total of 14 patients undergoing ACL reconstruction with a quadruple ST - GT graft by the same orthopaedic surgeon participated in this study. Pre-operative evaluation included determination of ST and GT CSA area using US and MRI. (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 10, 2015 Category: Neurology Authors: Nikiforos Galanis, Matthaios Savvidis, Ioannis Tsifountoudis, George Gkouvas, Ilias Alafropatis, Ioannis Kirkos, Eleftherios Kellis Source Type: research

Biceps femoris and semitendinosus tendon/aponeurosis strain during passive and active (isometric) conditions
The purpose of this study was to quantify strain and elongation of the long head of the biceps femoris (BFlh) and the semitendinosus (ST) tendon/aponeurosis. Forty participants performed passive knee extension trials from 90° of knee flexion to full extension (0°) followed by ramp isometric contractions of the knee flexors at 0, 45 and 90° of knee flexion. Two ultrasound probes were used to visualize the displacement of BFlh and ST tendon/aponeurosis. Three-way analysis of variance designs indicated that: (a) Tendon/aponeurosis (passive) elongation and strain were higher for the BFlh than the ST as the knee was passivel...
Source: Journal of Electromyography and Kinesiology - December 10, 2015 Category: Neurology Authors: Eleftherios Kellis Source Type: research

Ciliary muscle contraction force and trapezius muscle activity during manual tracking of a moving visual target
Previous studies have shown an association of visual demands during near work and increased activity of the trapezius muscle. Those studies were conducted under stationary postural conditions with fixed gaze and artificial visual load. The present study investigated the relationship between ciliary muscle contraction force and trapezius muscle activity across individuals during performance of a natural dynamic motor task under free gaze conditions. Participants (N=11) tracked a moving visual target with a digital pen on a computer screen. (Source: Journal of Electromyography and Kinesiology)
Source: Journal of Electromyography and Kinesiology - December 9, 2015 Category: Neurology Authors: Dmitry Domkin, Mikael Forsman, Hans O. Richter Source Type: research

Motor unit firing rates of the gastrocnemii during maximal brief steady-state contractions in humans
The human triceps surae (soleus, medial (MG) and lateral (LG) gastrocnemii) is complex and important for posture and gait. The soleus exhibits markedly low motor unit firing rates (MUFRs; ∼16Hz) during maximal voluntary isometric contraction (MVC) than other limb muscles, but this information is unknown for the MG and LG. During multiple visits, subjects performed a series of 5-7, ∼7-s plantar flexor MVCs with tungsten microelectrodes inserted into the MG and LG. During a separate testing session, another group of subjects performed submaximal isometric contractions at 25, 50, and 75% MVC with inserted fine-wires in th...
Source: Journal of Electromyography and Kinesiology - November 30, 2015 Category: Neurology Authors: Mitchell T. Graham, Charles L. Rice, Brian H. Dalton Source Type: research