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Physiological Reports Mar 2022Horses' muscular tension during acute stress remains unexplored. Our aim was to assess muscular, behavioral, cortisol, and hematocrit responses to social isolation...
Horses' muscular tension during acute stress remains unexplored. Our aim was to assess muscular, behavioral, cortisol, and hematocrit responses to social isolation (ISO), novel object exposure (NOV), and sham clipping (CLIP). Altered stress responses were expected. Eight mature Standardbred horses (four mares and four geldings) were exposed to acute stressors and a control period (CON) in a balanced, replicated 4×4 Latin Square experimental design with 3 min treatment periods and 10 min washout periods. Surface electromyography collected from the masseter, brachiocephalas, cervical trapezius, and longissimus dorsi was processed to derive average rectified value (ARV) and median frequency (MF) during the initial, middle, and final 30 s of treatments. ARV and MF data were log transformed then analyzed using a mixed model, repeated measures ANOVA along with plasma cortisol and hematocrit. Behavior data were analyzed using a negative binomial distribution mixed model ANOVA. CLIP resulted in greater (p < 0.05) log ARV in the masseter (1.5 + 1.5%, mean + SD) and brachiocepahlas (2.2 + 2.0%) than CON (-1.2 + 1.4%, 0.1 + 1.5%). ISO resulted in greater (p < 0.05) log ARV in the masseter (0.2 + 1.3%) and cervical trapezius (0.6 + 1.3%) than CON (-1.2 + 1.4%, -1.0 + 1.7%). ISO increased (p < 0.05) the total number of stress-related behaviors and hematocrit. No changes in cortisol were observed. We suggest that muscular tension can be used as an indicator of acute stress in horses. Incorporating muscle activity into an array of measurements may provide a more nuanced understanding of stress responses.
Topics: Animals; Electromyography; Female; Horses; Hydrocortisone; Male; Muscle Tonus
PubMed: 35307975
DOI: 10.14814/phy2.15220 -
Clinical and Experimental Pharmacology... Jul 20081. Duchenne muscular dystrophy (DMD), a severe muscle wasting disease of young boys with an incidence of one in every 3000, results from a mutation in the gene that... (Comparative Study)
Comparative Study Review
1. Duchenne muscular dystrophy (DMD), a severe muscle wasting disease of young boys with an incidence of one in every 3000, results from a mutation in the gene that encodes dystrophin. The absence of dystrophin expression in skeletal muscles and heart results in the degeneration of muscle fibres and, consequently, severe muscle weakness and wasting. The mdx mouse discovered in 1984, with some adjustments for differences, has proven to be an invaluable model for scientific investigations of dystrophy. 2. The development of the diaphagm strip preparation provided an ideal experimental model for investigations of skeletal muscle impairments in structure and function induced by interactions of disease- and age-related factors. Unlike the limb muscles of the mdx mouse, which show adaptive changes in structure and function, the diaphragm strip preparation reflects accurately the deterioration in muscle structure and function observed in boys with DMD. 3. The advent of sophisticated servo motors and force transducers interfaced with state-of-the-art software packages to drive complex experimental designs during the 1990s greatly enhanced the capability of the mdx mouse and the diaphragm strip preparation to evaluate more accurately the impact of the disease on the structure-function relationships throughout the life span of the mouse. 4. Finally, during the 1990s and through the early years of the 21st century, many promising, sophisticated genetic techniques have been designed to ameliorate the devastating impact of muscular dystrophy on the structure and function of skeletal muscles. During this period of rapid development of promising genetic therapies, the combination of the mdx mouse and the diaphragm strip preparation has provided an ideal model for the evaluation of the success, or failure, of these genetic techniques to improve dystrophic muscle structure, function or both. With the 2 year life span of the mdx mouse, the impact of age-related effects can be studied in this model.
Topics: Animals; Diaphragm; Disease Models, Animal; Genetic Therapy; In Vitro Techniques; Mice; Mice, Inbred mdx; Muscle Tonus; Muscular Dystrophy, Duchenne
PubMed: 18215182
DOI: 10.1111/j.1440-1681.2007.04865.x -
The American Journal of Case Reports Oct 2018BACKGROUND The aim of the present study was to investigate the effect of horizontal whole-body vibration (WBV) training on trunk and lower-extremity muscle tone and... (Review)
Review
BACKGROUND The aim of the present study was to investigate the effect of horizontal whole-body vibration (WBV) training on trunk and lower-extremity muscle tone and activation, balance, and gait in a child with spastic diplegia cerebral palsy. CASE REPORT A 10-year-old male with spastic diplegia cerebral palsy received horizontal WBV training followed by conventional physiotherapy (50 min per day, 12 days per month), but only conventional physiotherapy during followup. Muscle tone was assessed using the Modified Ashworth Scale (MAS) and muscle activation with surface electromyography. Balance was assessed using the Timed Up and Go test (TUG) and Pediatric Balance Scale (PBS), and gait parameters were assessed using the GAITRite system. Assessment was performed at 3 points: pre-intervention, post-intervention, and follow-up. Following the intervention, MAS decreased in both the hip extensor and right ankle plantar flexor. Muscle activation increased post-intervention in the bilateral erector spinae (ES), rectus abdominis (RA), rectus femoris (RF), and right tibialis anterior (TA) during standing, and in the left RA, bilateral RF, gastrocnemius (GCM), and left TA during squatting. At follow-up, activation increased in the right ES, left RA, and RF during standing. At post-intervention and follow-up, improvement was observed in PBS score, gait velocity, right step length, and right stride length, with decreased single-leg support time, and double support and toe deviation angle. CONCLUSIONS Horizontal WBV training can safely and effectively maintain and improve physical performance and can be considered for inclusion in rehabilitation programs.
Topics: Cerebral Palsy; Child; Follow-Up Studies; Gait; Humans; Lower Extremity; Male; Muscle Tonus; Patient Positioning; Postural Balance; Risk Assessment; Severity of Illness Index; Thorax; Treatment Outcome; Vibration
PubMed: 30377290
DOI: 10.12659/AJCR.910468 -
Journal of Sports Science & Medicine Mar 2021Increased muscle stiffness of the pectoralis minor (PMi) could deteriorate shoulder function. Stretching is useful for maintaining and improving muscle stiffness in... (Randomized Controlled Trial)
Randomized Controlled Trial
Increased muscle stiffness of the pectoralis minor (PMi) could deteriorate shoulder function. Stretching is useful for maintaining and improving muscle stiffness in rehabilitation and sport practice. However, the acute and prolonged effect of stretching on the PMi muscle stiffness is unclear due to limited methodology for assessing individual muscle stiffness. Using shear wave elastography, we explored the responses of shear modulus to stretching in the PMi over time. The first experiment (n = 20) aimed to clarify the acute change in the shear modulus during stretching. The shear modulus was measured at intervals of 30 s × 10 sets. The second experiment (n = 16) aimed to observe and compare the prolonged effect of different durations of stretching on the shear modulus. Short and long stretching duration groups underwent 30s × 1 set and 30s × 10 sets, respectively. The assessments of shear modulus were conducted before, immediately after, and at 5, 10, and 15 min post-stretching. In experiment I, the shear modulus decreased immediately after a bout (30 s) of stretching (p < 0.001, change: -2.3 kPa, effect size: = 0.72) and further decreased after 3 repetitions (i.e., 90 s) of stretching (p = 0.03, change: -1.0 kPa, effect size: = 0.53). In experiment II, the change in the shear modulus after stretching was greater in the long duration group than in the short duration group (p = 0.013, group mean difference: -2.5 kPa, partial = 0.36). The shear modulus of PMi decreased immediately after stretching, and stretching for a long duration was promising to maintain the decreased shear modulus. The acute and prolonged effects on the PMi shear modulus provide information relevant to minimum and persistent stretching time in rehabilitation and sport practice.
Topics: Adult; Analysis of Variance; Biomechanical Phenomena; Elastic Modulus; Elasticity Imaging Techniques; Humans; Male; Muscle Stretching Exercises; Muscle Tonus; Pectoralis Muscles; Time Factors
PubMed: 33707982
DOI: 10.52082/jssm.2021.17 -
Der Nervenarzt Dec 2013Spasticity develops as a consequence of damage to the central nervous system (CNS). Clinically, spasticity is characterized by muscle hypertension and exaggerated... (Review)
Review
Spasticity develops as a consequence of damage to the central nervous system (CNS). Clinically, spasticity is characterized by muscle hypertension and exaggerated reflexes and is associated with varying degrees of paresis. Together this results in the syndrome of spastic paresis. Patients suffer from impeded and retarded movement ability. Electrophysiological investigations of functional arm and leg movements (e.g. in walking) show a reduced activation of arm and leg muscles which can be explained by the loss of activating signals from motor brain centers and functional reflex systems. This effect predominates over the increased tendon-reflex activity. The reduced muscle activation caused by paresis is partially compensated by structural alterations of the muscle fibers (e.g. loss of sarcomeres). For this reason a functional improvement mostly cannot be achieved by antispastic medication which targets the deactivation of tendon-reflexes. However, they are useful in immobilized patients. In mobile patients functional improvement can be achieved by functional training which is accompanied by an adapted, i.e. reduced, spastic muscle tone.
Topics: Central Nervous System; Combined Modality Therapy; Humans; Mobility Limitation; Muscle Hypertonia; Muscle Spasticity; Muscle Tonus; Muscle, Skeletal; Paraplegia; Parasympatholytics; Physical Therapy Modalities; Reflex, Abnormal; Reflex, Stretch; Treatment Outcome
PubMed: 24271110
DOI: 10.1007/s00115-013-3933-2 -
Journal of Dental Research Apr 2016The role of masticatory muscle activation on pain in temporomandibular muscle and joint disorders (TMJD) is controversial. This single-group, prospective panel study...
The role of masticatory muscle activation on pain in temporomandibular muscle and joint disorders (TMJD) is controversial. This single-group, prospective panel study examined the relationships among masticatory muscle tension, emotional distress, and TMJD pain in a sample of 7,023 observations obtained from 171 individuals using longitudinal multilevel modeling. Three main hypotheses were tested. The first posited that emotional distress and muscle tension directly influenced pain (hypothesis 1a: Distress → TMJD Pain; hypothesis 1b: Muscle Tension → TMJD Pain). The second posited that emotional distress directly influenced muscle tension (Distress → Muscle Tension), and the third posited that the effect of emotional distress on pain was mediated by muscle tension (Distress → Muscle Tension → TMJD pain). We also examined the fit of the data to possible alternative models. All the data used in this study were collected via an experience sampling methodology. The fit of the preferred models was better than that of the alternative models, with the preferred models explaining large proportions of the data, especially for level 2 variance (hypothesis 1a = 41% variance; hypothesis 1b = 69% variance; hypothesis 2 = 48% variance). In the mediation model, the addition of muscle tension to the model reduced the impact of emotional distress. The findings support a causal role for masticatory muscle tension in TMJD pain. Clinically, the results suggest that addressing tension and other oral parafunctions in those diagnosed with TMJDs should be an important part of the conservative, noninvasive care of individuals diagnosed with the myofascial pain or arthralgia of TMJD.
Topics: Adult; Facial Pain; Female; Humans; Linear Models; Longitudinal Studies; Male; Masticatory Muscles; Muscle Tonus; Pain Measurement; Prospective Studies; Risk Factors; Stress, Psychological; Temporomandibular Joint Disorders
PubMed: 26758381
DOI: 10.1177/0022034515625216 -
The Laryngoscope Oct 2023The purpose of this study was to determine whether automated estimates of vocal creak would differentiate speakers with adductor laryngeal dystonia (AdLD) from speakers...
OBJECTIVE
The purpose of this study was to determine whether automated estimates of vocal creak would differentiate speakers with adductor laryngeal dystonia (AdLD) from speakers with muscle tension dysphonia (MTD) and speakers without voice disorders.
METHODS
Sixteen speakers with AdLD, sixteen speakers with MTD, and sixteen speakers without voice disorders were recorded in a quiet environment reading aloud a standard paragraph. An open-source creak detector was used to calculate the percentage of creak (% creak) in each of the speaker's six recorded sentences.
RESULTS
A Kruskal-Wallis one-way analysis of variance revealed a statistically significant effect of group on the % creak with a large effect size. Pairwise Wilcoxon tests revealed a statistically significant difference in % creak between speakers with AdLD and controls as well as between speakers with AdLD and MTD. Receiver operating characteristic curve analyses indicated that % creak differentiated AdLD from both controls and speakers with MTD with high sensitivity and specificity (area under the curve statistics of 0.94 and 0.86, respectively).
CONCLUSION
Percentage of creak as calculated by an automated creak detector may be useful as a quantitative indicator of AdLD, demonstrating the potential for use as a screening tool or to aid in a differential diagnosis.
LEVEL OF EVIDENCE
3 Laryngoscope, 133:2687-2694, 2023.
Topics: Humans; Dysphonia; Muscle Tonus; Dystonia; Voice Quality; Voice; Laryngeal Muscles
PubMed: 36715109
DOI: 10.1002/lary.30588 -
Medical Science Monitor : International... Jan 2022BACKGROUND The aims of this study were to (1) calculate the correlation between different tensile force levels and corresponding muscle stiffness both in vitro and in...
BACKGROUND The aims of this study were to (1) calculate the correlation between different tensile force levels and corresponding muscle stiffness both in vitro and in vivo; (2) determine whether muscle stiffness assessed using a MyotonPRO myotonometer can be used to accurately estimate muscle activity level; and (3) evaluate the inter-operator reliability of MyotonPRO-based measurement in assessing biceps brachii muscle (BBM) stiffness. MATERIAL AND METHODS In Experiment I, muscle stiffness, as measured using the MyotonPRO, was obtained at 0 N, 2 N, 4 N, 6 N, 8 N, and 10 N of applied force on 6 fresh medial gastrocnemius muscle specimens. In Experiment II, 11 healthy subjects were recruited. BBM stiffness, assessed by the same device, was obtained at different tensile force levels, from 0 to 50% of maximal voluntary contraction (MVC). For the reliability test, the score for each subject was quantified by 2 operators (I and II), thrice, at 30-minute intervals on the same day. RESULTS A strong correlation was found between the different tensile force levels, which corresponded to muscle stiffness in vitro (r=0.71-0.95, all P<0.05). In vivo, muscle stiffness increased linearly with an increase of the tensile force levels from 0 to 50% of MVC (r=0.99, P=0.00) and there was a significant difference in BBM stiffness among the incremental isometric tasks (F [1.76, 17.60]=91.52, P=0.00). The inter-operator reliability for the measurement of BBM stiffness was good (ICC=0.86). CONCLUSIONS Our findings indicate that muscle stiffness measured using the MyotonPRO is strongly related to muscle activity level and that the MyotonPRO is a feasible tool for quantifying BBM stiffness as well as for quantifying changes in MVC levels.
Topics: Adult; Animals; Chickens; Elasticity; Equipment Design; Feasibility Studies; Humans; Models, Animal; Muscle Contraction; Muscle Tonus; Muscle, Skeletal; Reference Values; Reproducibility of Results
PubMed: 35087016
DOI: 10.12659/MSM.934121 -
Journal of Biomechanics Jul 2018Intramuscular pressure (IMP) is the fluid pressure generated within skeletal muscle and directly reflects individual muscle tension. The purpose of this study was to...
INTRODUCTION
Intramuscular pressure (IMP) is the fluid pressure generated within skeletal muscle and directly reflects individual muscle tension. The purpose of this study was to assess the development of force, IMP, and electromyography (EMG) in the tibialis anterior (TA) muscle during ramped isometric contractions and evaluate electromechanical delay (EMD).
METHODS
Force, EMG, and IMP were simultaneously measured during ramped isometric contractions in eight young, healthy human subjects. The EMD between the onset of force and EMG activity (Δt-EMG force) and the onset of IMP and EMG activity (Δt EMG-IMP) were calculated.
RESULTS
A statistically significant difference (p < 0.05) was found between the mean force-EMG EMD (36 ± 31 ms) and the mean IMP-EMG EMD (3 ± 21 ms).
CONCLUSIONS
IMP reflects changes in muscle tension due to the contractile muscle elements.
Topics: Adult; Electromyography; Female; Humans; Isometric Contraction; Male; Muscle Tonus; Muscle, Skeletal; Pressure; Rotation; Young Adult
PubMed: 29908653
DOI: 10.1016/j.jbiomech.2018.05.029 -
Allergology International : Official... Sep 2011
Topics: Humans; Male; Muscle Tonus; Muscle, Skeletal; Skin
PubMed: 21502807
DOI: 10.2332/allergolint.10-LE-0286