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Muscle co contraction

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https://www.readbyqxmd.com/read/27922972/idiopathic-synkinesis-of-the-facial-musculature-oculo-nasal-oculo-zygomatic-and-fronto-nasal-synkinesis
#1
Sujin Bahk, SeungHwan Hwang, SuRak Eo
Facial synkinesis is the simultaneous contraction of the certain facial musculature accompanying a motion of designated muscle in the face. With the exception of rare afflictions that are congenital in origin, most patients develop as a sequel to facial nerve paralysis due to trauma, tumor, and surgical injury. As an idiopathic congenital form, oculo-nasal synkinesis which reveals co-contraction of orbicularis oculi and the compressor narium minor muscles which are innervated by separate branches of the facial nerve have been already reported...
December 5, 2016: Journal of Craniofacial Surgery
https://www.readbyqxmd.com/read/27918960/effects-of-knee-action-phase-and-fatigue-on-rectus-femoris-and-biceps-femoris-co-activation-during-the-eggbeater-kick
#2
Nuno Oliveira, Ross H Sanders
The purpose of this study was to investigate the effect of knee extension/flexion and fatigue on muscle co-activation of the Rectus Femoris (RF) and Biceps Femoris (BF) during the eggbeater kick. Ten national level male water polo players executed eggbeater kicks at maximum effort for the duration of the test. The eggbeater kick cycle was divided into four phases (FLX1, FLX2, EXT1, EXT2). Surface electromyographs were recorded from RF and BF. EMG activity normalized to the maximum voluntary isometric contraction, muscle co-activation (CCI) and angular velocity (AV) of the right and left knee were calculated...
December 2, 2016: Human Movement Science
https://www.readbyqxmd.com/read/27914205/mitochondrial-genotype-and-phenotypic-plasticity-of-gene-expression-in-response-to-cold-acclimation-in-killifish
#3
Timothy M Healy, Heather J Bryant, Patricia M Schulte
Adjustments of aerobic metabolic processes are critical components of organismal responses to environmental change that require tight co-ordination between the nuclear and mitochondrial genomes. Intraspecific differences in mitochondrial genotype can affect gene transcription in both genomes. Thus, variation in mitochondrial genotype may be associated with differences in the plasticity of gene expression when organisms are faced with changes in environmental conditions. Cold acclimation is known to result in metabolic responses involving increases in mitochondrial amount and capacity, suggesting that low temperatures may pose a particular challenge when co-ordinating the functions of the nuclear and mitochondrial genomes...
December 3, 2016: Molecular Ecology
https://www.readbyqxmd.com/read/27911944/specific-stimuli-induce-specific-adaptations-sensorimotor-training-vs-reactive-balance-training
#4
Kathrin Freyler, Anne Krause, Albert Gollhofer, Ramona Ritzmann
Typically, balance training has been used as an intervention paradigm either as static or as reactive balance training. Possible differences in functional outcomes between the two modalities have not been profoundly studied. The objective of the study was to investigate the specificity of neuromuscular adaptations in response to two balance intervention modalities within test and intervention paradigms containing characteristics of both profiles: classical sensorimotor training (SMT) referring to a static ledger pivoting around the ankle joint vs...
2016: PloS One
https://www.readbyqxmd.com/read/27909885/kinematics-and-muscle-activation-patterns-during-a-maximal-voluntary-rate-activity-in-healthy-elderly-and-young-adults
#5
Eva Chadnova, Nancy St-Onge, Richard Courtemanche, Robert D Kilgour
BACKGROUND: Maximal voluntary rate (MVR) performance tasks can provide important age-related information to the limiting factors associated with movement and the development of fatigue. AIM: To determine whether kinematic and muscle activation patterns during an MVR task differ between young and older adults. METHODS: We continuously measured frequency, amplitude, peak velocity, index of co-contraction and median frequencies of the index finger flexors and extensors during a 20-s MVR task in 10 young and 10 older subjects...
December 1, 2016: Aging Clinical and Experimental Research
https://www.readbyqxmd.com/read/27906129/the-evolutionary-origin-of-bilaterian-smooth-and-striated-myocytes
#6
Thibaut Brunet, Antje Hl Fischer, Patrick Rh Steinmetz, Antonella Lauri, Paola Bertucci, Detlev Arendt
The dichotomy between smooth and striated myocytes is fundamental for bilaterian musculature, but its evolutionary origin is unsolved. In particular, interrelationships of visceral smooth muscles remain unclear. Absent in fly and nematode, they have not yet been characterized molecularly outside vertebrates. Here, we characterize expression profile, ultrastructure, contractility and innervation of the musculature in the marine annelid Platynereis dumerilii and identify smooth muscles around the midgut, hindgut and heart that resemble their vertebrate counterparts in molecular fingerprint, contraction speed, and nervous control...
December 1, 2016: ELife
https://www.readbyqxmd.com/read/27859527/gait-mechanics-and-second-acl-rupture-implications-for-delaying-return-to-sport
#7
Jacob J Capin, Ashutosh Khandha, Ryan Zarzycki, Kurt Manal, Thomas S Buchanan, Lynn Snyder-Mackler
Second anterior cruciate ligament rupture is a common and devastating injury among young women who return to sport after ACL reconstruction, but it is inadequately understood. The purpose of this study was to compare gait biomechanics and return-to-sport time frames in a matched cohort of young female athletes who, after primary ACLR, returned to sport without re-injury or sustained a second ACL injury. Approximately 6 months after primary reconstruction, 14 young women (age 16 ± 2 years) involved in jumping, cutting, and pivoting sports underwent motion analysis testing after physical therapy and impairment resolution...
November 9, 2016: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
https://www.readbyqxmd.com/read/27854219/sil1-mutant-mice-elucidate-chaperone-function-in-neurological-disorders
#8
Stephan Buchkremer, José Andrés González Coraspe, Joachim Weis, Andreas Roos
Chaperone dysfunction leading to the build-up of misfolded proteins could frequently be linked to clinical manifestations also affecting the nervous system and the skeletal muscle. In addition, increase in chaperone function is beneficial to antagonize protein aggregation and thus represents a promising target for therapeutic concepts for many genetic and acquired chaperonopathies. However, little is known on the precise molecular mechanisms defining the cell and tissue abnormalities in the case of impaired chaperone function as well as on underlying effects in the case of compensatory up-regulation of chaperones...
May 27, 2016: Journal of Neuromuscular Diseases
https://www.readbyqxmd.com/read/27825072/surface-emg-analysis-for-the-quantification-of-thigh-muscle-dynamic-co-contractions-during-normal-gait
#9
Annachiara Strazza, Alessandro Mengarelli, Sandro Fioretti, Laura Burattini, Valentina Agostini, Marco Knaflitz, Francesco Di Nardo
The research purpose was to quantify the co-contraction patterns of quadriceps femoris (QF) vs. hamstring muscles during free walking, in terms of onset-offset muscular activation, excitation intensity, and occurrence frequency. Statistical gait analysis was performed on surface-EMG signals from vastus lateralis (VL), rectus femoris (RF), and medial hamstrings (MH), in 16315 strides walked by 30 healthy young adults. Results showed full superimpositions of MH with both VL and RF activity from terminal swing, 80 to 100% of gait cycle (GC), to the successive loading response (≈0-15% of GC), in around 90% of the considered strides...
January 2017: Gait & Posture
https://www.readbyqxmd.com/read/27810649/the-influence-of-digital-filter-type-amplitude-normalisation-method-and-co-contraction-algorithm-on-clinically-relevant-surface-electromyography-data-during-clinical-movement-assessments
#10
Daniel Devaprakash, Gillian J Weir, James J Dunne, Jacqueline A Alderson, Cyril J Donnelly
There is a large and growing body of surface electromyography (sEMG) research using laboratory-specific signal processing procedures (i.e., digital filter type and amplitude normalisation protocols) and data analyses methods (i.e., co-contraction algorithms) to acquire practically meaningful information from these data. As a result, the ability to compare sEMG results between studies is, and continues to be challenging. The aim of this study was to determine if digital filter type, amplitude normalisation method, and co-contraction algorithm could influence the practical or clinical interpretation of processed sEMG data...
December 2016: Journal of Electromyography and Kinesiology
https://www.readbyqxmd.com/read/27775537/can-a-soft-robotic-probe-use-stiffness-control-like-a-human-finger-to-improve-efficacy-of-haptic-perception
#11
Nantachai Sornkarn, Thrishantha Nanayakkara
When humans are asked to palpate a soft tissue to locate a hard nodule, they regulate the stiffness, speed, and force of the finger during examination. If we understand the relationship between these behavioral variables and haptic information gain (transfer entropy) during manual probing, we can improve the efficacy of soft robotic probes for soft tissue palpation, such as in tumor localization in minimally invasive surgery. Here, we recorded the muscle co-contraction activity of the finger using EMG sensors to address the question as to whether joint stiffness control during manual palpation plays an important role in the haptic information gain...
October 19, 2016: IEEE Transactions on Haptics
https://www.readbyqxmd.com/read/27773588/differences-in-active-range-of-motion-measurements-in-the-upper-extremity-of-patients-with-writer-s-cramp-compared-with-healthy-controls
#12
Prachaya Srivanitchapoom, Ejaz A Shamim, Pierre Diomi, Takaaki Hattori, Sanjay Pandey, Sherry Vorbach, Jung E Park, Tianxia Wu, Sungyoung Auh, Mark Hallett
STUDY DESIGN: Exploratory case-control study. INTRODUCTION: Writer's cramp (WC) is a type of focal hand dystonia. The central nervous system plays a role in its pathophysiology, but abnormalities in the affected musculoskeletal components may also be relevant. PURPOSE OF THE STUDY: We compared the active range of motion (ROM) in patients with WC and healthy volunteers (HVs) and correlated the findings with disease duration and severity. METHODS: Affected limb joints were measured with goniometers...
October 2016: Journal of Hand Therapy: Official Journal of the American Society of Hand Therapists
https://www.readbyqxmd.com/read/27756572/musculoskeletal-modeling-of-human-lower-limb-during-normal-walking-one-legged-forward-hopping-and-side-jumping-comparison-of-measured-emg-and-predicted-muscle-activity-patterns
#13
A D Wibawa, N Verdonschot, J P K Halbertsma, J G M Burgerhof, R L Diercks, G J Verkerke
This study focused on comparing muscle activities predicted by the Musculoskeletal Modeling System with EMG from ten healthy subjects who performed normal walking, one-legged forward hopping and side jumping. Eight EMG electrodes measured the activity of eight right leg muscles. Specific thresholds per muscle were applied on the EMG prior comparison. These thresholds were determined by equalizing the duration of EMG to AMS muscle activity. Three graph variables, number of onsets, offsets and hills were used to quantify the level of agreement by using Cohen׳s kappa analysis...
October 6, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27753740/correlated-emg-oscillations-between-antagonists-during-co-contraction-in-men
#14
Yasuhide Yoshitake, Hiroaki Kanehisa, Minoru Shinohara
PURPOSE: The purpose of this study was to determine the modulation of common low-frequency oscillations in pools of motor units across antagonistic muscles due to the difference in the activation level of pools of spinal motor neurons and the presence of neuromuscular fatigue during intended co-contraction. METHODS: Ten healthy young men (21.8 ± 1.5 yr) performed intended steady co-contractions of elbow flexors and extensors at maximal and a submaximal (10% of maximal electromyogram, EMG) effort...
October 6, 2016: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/27751947/mrtf-a-signaling-regulates-the-acquisition-of-the-contractile-phenotype-in-dedifferentiated-chondrocytes
#15
Justin Parreno, Sneha Raju, Po-Han Wu, Rita A Kandel
Chondrocyte culture as a monolayer for cell number expansion results in dedifferentiation whereby expanded cells acquire contractile features and increased actin polymerization status. This study determined whether the actin polymerization based signaling pathway, myocardin-related transcription factor-a (MRTF-A) is involved in regulating this contractile phenotype. Serial passaging of chondrocytes in monolayer culture to passage 2 resulted in increased gene and protein expression of the contractile molecules alpha-smooth muscle actin, transgelin and vinculin compared to non-passaged, primary cells...
October 14, 2016: Matrix Biology: Journal of the International Society for Matrix Biology
https://www.readbyqxmd.com/read/27721087/selective-activation-of-lower-leg-muscles-during-maximum-voluntary-isometric-contractions
#16
Marco Hagen, Gerrit Schwiertz, Karl B Landorf, Hylton B Menz, George S Murley
The pronators and supinators play a key role in the medio-lateral stability of the ankle joint complex (i.e. talo-crural and subtalar joints). We hypothesized that each shank muscle has a specific activation pattern determined by its anatomical course around the axes of the subtalar and talo-crural joints. A secondary objective was to examine the effect of foot posture on these activation patterns. Forty-nine young adults (25 normal-arched feet, 24 flat-arched feet) performed maximum voluntary isometric contractions against manual resistance in four movement directions: plantarflexion (PF), dorsiflexion (DF), pronation (PRO) and supination (SUP)...
December 2016: Human Movement Science
https://www.readbyqxmd.com/read/27716255/alterations-in-neuromuscular-function-in-girls-with-generalized-joint-hypermobility
#17
Bente Rona Jensen, Jesper Sandfeld, Pia Sandfeld Melcher, Katrine Lyders Johansen, Peter Hendriksen, Birgit Juul-Kristensen
BACKGROUND: Generalized Joint Hypermobility (GJH) is associated with increased risk of musculoskeletal joint pain. We investigated neuromuscular performance and muscle activation strategy. METHODS: Girls with GJH and non-GJH (NGJH) performed isometric knee flexions (90°,110°,130°), and extensions (90°) at 20 % Maximum Voluntary Contraction, and explosive isometric knee flexions while sitting. EMG was recorded from knee flexor and extensor muscles. RESULTS: Early rate of torque development was 53 % faster for GJH...
October 3, 2016: BMC Musculoskeletal Disorders
https://www.readbyqxmd.com/read/27696494/muscle-and-nerve-net-organization-in-stalked-jellyfish-medusozoa-staurozoa
#18
Hannah E Westlake, Louise R Page
Staurozoan cnidarians display an unusual combination of polyp and medusa characteristics and their morphology may be informative about the evolutionary origin of medusae. We studied neuromuscular morphology of two staurozoans, Haliclystus 'sanjuanensis' and Manania handi, using whole mount immunohistochemistry with antibodies against FMRFamide and α-tubulin to label neurons and phalloidin to label muscles. All muscles appeared to lack striations. Longitudinal interradial muscles are probable homologues of stalk muscles in scyphopolyps, but in adult staurozoans they are elaborated to inwardly flex marginal lobes of the calyx during prey capture; these muscles are pennate in M...
October 2, 2016: Journal of Morphology
https://www.readbyqxmd.com/read/27690099/ex-vivo-smooth-muscle-pharmacological-effects-of-a-novel-bradykinin-related-peptide-and-its-analogue-from-chinese-large-odorous-frog-odorrana-livida-skin-secretions
#19
Jie Xiang, Hui Wang, Chengbang Ma, Mei Zhou, Yuxin Wu, Lei Wang, Shaodong Guo, Tianbao Chen, Chris Shaw
Bradykinin-related peptides (BRPs) are one of the most extensively studied frog secretions-derived peptide families identified from many amphibian species. The diverse primary structures of BRPs have been proven essential for providing valuable information in understanding basic mechanisms associated with drug modification. Here, we isolated, identified and characterized a dodeca-BRP (RAP-L1, T6-BK), with primary structure RAPLPPGFTPFR, from the skin secretions of Chinese large odorous frogs, Odorrana livida...
2016: Toxins
https://www.readbyqxmd.com/read/27684529/lower-limb-joint-stiffness-and-muscle-co-contraction-adaptations-to-instability-footwear-during-locomotion
#20
Charlotte Apps, Thorsten Sterzing, Thomas O'Brien, Mark Lake
Unstable shoes (US) continually perturb gait which can train the lower limb musculature, but muscle co-contraction and potential joint stiffness strategies are not well understood. A shoe with a randomly perturbing midsole (IM) may enhance these adaptations. This study compares ankle and knee joint stiffness, and ankle muscle co-contraction during walking and running in US, IM and a control shoe in 18 healthy females. Ground reaction forces, three-dimensional kinematics and electromyography of the gastrocnemius medialis and tibialis anterior were recorded...
December 2016: Journal of Electromyography and Kinesiology
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