Postural Muscle Tone in the Body Axis of Healthy Humans

2006 ◽  
Vol 96 (5) ◽  
pp. 2678-2687 ◽  
Author(s):  
Victor Gurfinkel ◽  
Timothy W. Cacciatore ◽  
Paul Cordo ◽  
Fay Horak ◽  
John Nutt ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Tone ◽  
Critical Role ◽  
Axial Rotation ◽  
The Body ◽  
Neutral Position ◽  
Healthy Humans ◽  
Postural Muscle ◽  
Nonlinear Features ◽  
Postural Tone

Across the entire human body, postural tone might play its most critical role in the body's axis because the axis joins the four limbs and head into a single functioning unit during complex motor tasks as well as in static postures. Although postural tone is commonly viewed as low-level, tonic motor activity, we hypothesized that postural tone is both tonically and dynamically regulated in the human axis even during quiet stance. Our results describe the vertical distribution of postural muscle tone in the neck, trunk, and hips of standing human adults. Each subject stood blindfolded on a platform that axially rotated the neck, trunk, or pelvis at 1°/s and ±10° relative to the neutral position (i.e., facing forward). The measured resistance to axial rotation was highest in the trunk and lowest in the neck and was characterized by several nonlinear features including short-range stiffness and hysteresis. In half of the subjects, axial muscle activity was relatively constant during axial rotation, and in the other half, muscle activity was modulated by lengthening and shortening reactions, i.e., decreasing activity in lengthening muscles and increasing activity in shortening muscles, respectively. Axial resistance to rotation was reduced in subjects whose muscle activity was modulated. The results indicate that axial tone is modulated sensitively and dynamically, this control originates, at least in part, from tonic lengthening and shortening reactions, and a similar type of control appears to exist for postural tone in the proximal muscles of the arm.

scholarly journals Effect of Using Ergobrass Ergonomic Supports on Postural Muscles in Trumpet, Trombone, and French Horn Players

2018 ◽  
Vol 33 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Kevin Price ◽  
Alan HD Watson
Keyword(s):  
Muscle Activity ◽  
Musculoskeletal Injury ◽  
Pectoralis Major ◽  
The Body ◽  
French Horn ◽  
Activity Levels ◽  
Brass Instruments ◽  
Postural Muscle ◽  
The Right ◽  
Postural Muscles

AIMS: Though ergonomic supports are widely used for many groups of instruments, they are rare for brass instruments, despite the instruments’ considerable weight. Musculoskeletal injury and postural problems are common among this group, and so, both adult and young players are likely to benefit from supports that reduce the load placed on the body. This study assessed the effects on postural muscle activity of a recently developed range of supports (Ergobrass) that use a rod to transfer the weight of the instrument to a harness or to the chair or floor. METHODS: Twenty conservatoire students (mean age [SD], 20.9 ± 0.5 yrs) of the trumpet, french horn, or trombone used the supports while playing short brass studies, either sitting or standing. Surface electromyography recordings were made from key postural muscles, and their activity levels were compared with and without the support. RESULTS: Statistically significant reductions (typically 15–30%) were present in many of the muscles when using the supports, though in some players they were much larger. The number of muscles affected was least with the lightest instruments (the trumpet), with the effects mainly in the left deltoid and trapezius muscles. Reductions for the horn were bilateral, principally in biceps, pectoralis major, and deltoid; while in the trombone, they were confined to the left side (pectoralis major, posterior deltoid, and trapezius), as the right arm is in constant use to move the slide. CONCLUSIONS: The supports are effective in reducing postural muscle activity and may be of particular benefit to injured or young players.

scholarly journals Functional Reaction of the Cardiovascular System to Irritation of Vestibular Receptors in Students Engaged in Different Types of Martial Arts

2022 ◽  
Vol 16 ◽  
pp. 96-104
Author(s):  
I. N. Medvedev ◽  
V. Yu. Karpov ◽  
O. N. Makurina ◽  
M. V. Eremin ◽  
A. V. Dorontsev ◽  
...  
Keyword(s):  
Cardiovascular System ◽  
Martial Arts ◽  
Muscle Activity ◽  
Muscle Tone ◽  
The Body ◽  
Current Position ◽  
Different Types ◽  
The Stability ◽  
Flow Of Information ◽  
Functional Reaction

Regular dosed physical activity in all cases has a tonic and healing effect on a person. Feasible muscle activity helps to improve the function of the heart, lungs, blood vessels and the nervous system. In martial arts, the reactivity of the vestibular apparatus is of great importance, providing the flow of information about the current position of the body in space, the success of movement in it and maintaining the stability of the posture due to the effective redistribution of muscle tone. Purpose of the work: to find out the dependence of the reaction of the cardiovascular system to the arising vestibular irritation in different types of martial arts. Martial arts classes help to increase the degree of vestibular stability. The statokinetic stability is very pronounced and increases in the course of hand-to-hand combat, which has a lot of moments with different severity of angular accelerations. The peculiarities of motor activity in any kind of martial arts inevitably affect the peculiarities of the reaction to the test with a change in the position of the head.

Osteopathic support of sportsmen during the annual training process

2020 ◽  
pp. 37-43 ◽  
Author(s):  
R. A. Yakupov ◽  
G. I. Safiullina ◽  
A. A. Safiullina ◽  
E. R. Burganov
Keyword(s):  
Musculoskeletal Diseases ◽  
Muscle Tone ◽  
The Body ◽  
Training Process ◽  
Health Maintenance ◽  
Osteopathic Treatment ◽  
Leading Position ◽  
Myofascial Syndrome ◽  
Sports Activities ◽  
Timely Treatment

Introduction. Modern sports places high demands on the functional systems of the body at all stages of the training and competitive processes. High loads create signifi cant background for the occurrence of musculoskeletal diseases, among which the myofascial syndrome (MFS) holds the leading position. MFS negatively affects the functional readiness of the sportsman′s body and is a risk factor for injuries of the musculoskeletal system. In this regard, timely treatment of MFS is important. It creates the conditions for the improvement of sports achievements, for health maintenance and sports longevity. Treatment of patients with MFS should include methods that normalize trophism and muscle tone. Given the problem of doping, the use of non-drug methods, including osteopathy, is preferable. The goal of research — to develop a system of monitoring and osteopathic correction of myofascial disorders (MFD) and to introduce it into the practice of medical and biological support for sportsmen of different categories and levels during the annual training process.Materials and methods. 93 sportsmen (45 women and 48 men), mean age 22,1±1,1 years, representing diffe rent sports were examined. The essence of the proposed system is regular clinical and electroneurophysiological monitoring of the body condition and preventive correction of myofascial disorders in order to exclude their infl uence on the success of sports activities.Results. It was established that the proposed system of monitoring and osteopathic correction led to a signifi cant reduction in clinical and electroneurophysiological manifestations both in local and in extensive forms of myofascial disorders, which allowed to maintain the optimal functional readiness of sportsmen throughout the entire annual training cycle.Conclusion. The system of monitoring and correction of MFS with the use of osteopathic treatment can be one of the elements of medical and biological support for sportsmen during the annual training process.

Updating long-held assumptions about fat stigma: For women, body shape plays a critical role

2020 ◽  
Author(s):  
Jaimie Krems ◽  
Steven L. Neuberg
Keyword(s):  
Body Shape ◽  
Critical Role ◽  
The Body ◽  
Theoretical Assumption ◽  
Obesity Stigma ◽  
Obese Female ◽  
Three Samples ◽  
Female Bodies ◽  
Different Parts ◽  
Fat Stigma

Heavier bodies—particularly female bodies—are stigmatized. Such fat stigma is pervasive, painful to experience, and may even facilitate weight gain, thereby perpetuating the obesity-stigma cycle. Leveraging research on functionally distinct forms of fat (deposited on different parts of the body), we propose that body shape plays an important but largely underappreciated role in fat stigma, above and beyond fat amount. Across three samples varying in participant ethnicity (White and Black Americans) and nation (U.S., India), patterns of fat stigma reveal that, as hypothesized, participants differently stigmatized equally-overweight or -obese female targets as a function of target shape, sometimes even more strongly stigmatizing targets with less rather than more body mass. Such findings suggest value in updating our understanding of fat stigma to include body shape and in querying a predominating, but often implicit, theoretical assumption that people simply view all fat as bad (and more fat as worse).

scholarly journals PPARs as Metabolic Sensors and Therapeutic Targets in Liver Diseases

2021 ◽  
Vol 22 (15) ◽  
pp. 8298
Author(s):  
Hugo Christian Monroy-Ramirez ◽  
Marina Galicia-Moreno ◽  
Ana Sandoval-Rodriguez ◽  
Alejandra Meza-Rios ◽  
Arturo Santos ◽  
...  
Keyword(s):  
Liver Diseases ◽  
Metabolic Regulation ◽  
Structural Changes ◽  
Critical Role ◽  
The Body ◽  
Molecular Characteristics ◽  
Signal Pathways ◽  
Virus Infections ◽  
Physiological Processes ◽  
Hepatic Level

Carbohydrates and lipids are two components of the diet that provide the necessary energy to carry out various physiological processes to help maintain homeostasis in the body. However, when the metabolism of both biomolecules is altered, development of various liver diseases takes place; such as metabolic-associated fatty liver diseases (MAFLD), hepatitis B and C virus infections, alcoholic liver disease (ALD), and in more severe cases, hepatocelular carcinoma (HCC). On the other hand, PPARs are a family of ligand-dependent transcription factors with an important role in the regulation of metabolic processes to hepatic level as well as in other organs. After interaction with specific ligands, PPARs are translocated to the nucleus, undergoing structural changes to regulate gene transcription involved in lipid metabolism, adipogenesis, inflammation and metabolic homeostasis. This review aims to provide updated data about PPARs’ critical role in liver metabolic regulation, and their involvement triggering the genesis of several liver diseases. Information is provided about their molecular characteristics, cell signal pathways, and the main pharmacological therapies that modulate their function, currently engaged in the clinic scenario, or in pharmacological development.

Postural adjustments for online corrections of arm movements in standing humans

2011 ◽  
Vol 105 (5) ◽  
pp. 2375-2388 ◽  
Author(s):  
Julia A. Leonard ◽  
Valeriya Gritsenko ◽  
Ryan Ouckama ◽  
Paul J. Stapley
Keyword(s):  
Muscle Activity ◽  
Arm Movements ◽  
Task Demands ◽  
Target Displacement ◽  
Postural Adjustments ◽  
Central Target ◽  
Postural Muscle ◽  
Online Corrections ◽  
Standing Humans ◽  
The Right

The aim of this study was to investigate how humans correct ongoing arm movements while standing. Specifically, we sought to understand whether the postural adjustments in the legs required for online corrections of arm movements are predictive or rely on feedback from the moving limb. To answer this question we measured online corrections in arm and leg muscles during pointing movements while standing. Nine healthy right-handed subjects reached with their dominant arm to a visual target in front of them and aligned with their midline. In some trials, the position of the target would switch from the central target to one of the other targets located 15°, 30°, or 45° to the right of the central (midline) target. For each target correction, we measured the time at which arm kinematics, ground reaction forces, and arm and leg muscle electromyogram significantly changed in response to the target displacement. Results show that postural adjustments in the left leg preceded kinematic corrections in the limb. The corrective postural muscle activity in the left leg consistently preceded the corrective reaching muscle activity in the right arm. Our results demonstrate that corrections of arm movements in response to target displacement during stance are preceded by postural adjustments in the leg contralateral to the direction of target shift. Furthermore, postural adjustments preceded both the hand trajectory correction and the arm-muscle activity responsible for it, which suggests that the central nervous system does not depend on feedback from the moving arm to modify body posture during voluntary movement. Instead, postural adjustments lead the online correction in the arm the same way they lead the initiation of voluntary arm movements. This suggests that forward models for voluntary movements executed during stance incorporate commands for posture that are produced on the basis of the required task demands.

The C-start escape response ofPolypterus senegalus: bilateral muscle activity and variation during stage 1 and 2

2002 ◽  
Vol 205 (17) ◽  
pp. 2591-2603 ◽  
Author(s):  
Eric D. Tytell ◽  
George V. Lauder
Keyword(s):  
Muscle Activity ◽  
Escape Response ◽  
High Speed ◽  
Wave Speed ◽  
Activity Patterns ◽  
Motor Pattern ◽  
The Body ◽  
Wide Range ◽  
Fast Start ◽  
Stage 1

SUMMARYThe fast-start escape response is the primary reflexive escape mechanism in a wide phylogenetic range of fishes. To add detail to previously reported novel muscle activity patterns during the escape response of the bichir, Polypterus, we analyzed escape kinematics and muscle activity patterns in Polypterus senegalus using high-speed video and electromyography (EMG). Five fish were filmed at 250 Hz while synchronously recording white muscle activity at five sites on both sides of the body simultaneously (10 sites in total). Body wave speed and center of mass velocity, acceleration and curvature were calculated from digitized outlines. Six EMG variables per channel were also measured to characterize the motor pattern. P. senegalus shows a wide range of activity patterns, from very strong responses, in which the head often touched the tail, to very weak responses. This variation in strength is significantly correlated with the stimulus and is mechanically driven by changes in stage 1 muscle activity duration. Besides these changes in duration, the stage 1 muscle activity is unusual because it has strong bilateral activity, although the observed contralateral activity is significantly weaker and shorter in duration than ipsilateral activity. Bilateral activity may stiffen the body, but it does so by a constant amount over the variation we observed; therefore, P. senegalus does not modulate fast-start wave speed by changing body stiffness. Escape responses almost always have stage 2 contralateral muscle activity, often only in the anterior third of the body. The magnitude of the stage 2 activity is the primary predictor of final escape velocity.

Anticipatory weight shift between arms when reaching from a crouched posture

2021 ◽  
Author(s):  
Rosemary Gallagher ◽  
Stephaine Perez ◽  
Derek DeLuca ◽  
Isaac L. Kurtzer
Keyword(s):  
Body Weight ◽  
Muscle Activity ◽  
Force Plate ◽  
Vertical Axis ◽  
The Body ◽  
Reaching Movements ◽  
Reactive Control ◽  
Step Initiation ◽  
Weight Shift ◽  
The Many

Reaching movements performed from a crouched body posture require a shift of body weight from both arms to one arm. This situation has remained unexamined despite the analogous load requirements during step initiation and the many studies of reaching from a seated or standing posture. To determine whether the body weight shift involves anticipatory or exclusively reactive control we obtained force plate records, hand kinematics, and arm muscle activity from 11 healthy right-handed participants. They performed reaching movements with their left and right arm in two speed contexts - 'comfortable' and 'as fast as possible' - and two postural contexts - a less stable knees-together posture and more stable knees-apart posture. Weight-shifts involved anticipatory postural actions (APA) by the reaching and stance arms that were opposing in the vertical axis and aligned in the side-to-side axis similar to APAs by the legs for step initiation. Weight-shift APAs were correlated in time and magnitude, present in both speed contexts, more vigorous with the knees placed together, and similar when reaching with the dominant or non-dominant arm. The initial weight-shift was preceded by bursts of muscle activity in the shoulder and elbow extensors (posterior deltoid and triceps lateral) of the reach arm and shoulder flexor (pectoralis major) of the stance arm which indicates their causal role; leg muscles may have indirectly contributed but were not recorded. The strong functional similarity of weight-shift APAs during crouched reaching to human stepping and cats reaching suggests that they are a core feature of posture-movement coordination.

Neuronal Sodium Leak Channel Is Responsible for the Detection of Sodium in the Rat Median Preoptic Nucleus

2011 ◽  
Vol 105 (2) ◽  
pp. 650-660 ◽  
Author(s):  
Christina Tremblay ◽  
Emmanuelle Berret ◽  
Mélaine Henry ◽  
Benjamin Nehmé ◽  
Louis Nadeau ◽  
...  
Keyword(s):  
Close Contact ◽  
Critical Role ◽  
Reversal Potential ◽  
Outward Current ◽  
The Body ◽  
Equilibrium Potential ◽  
Preoptic Nucleus ◽  
Leak Channel ◽  
Median Preoptic Nucleus ◽  
Electrophysiological Recordings

Sodium (Na+) ions are of primary importance for hydromineral and cardiovascular homeostasis, and the level of Na+ in the body fluid compartments [plasma and cerebrospinal fluid (CSF)] is precisely monitored in the hypothalamus. Glial cells seem to play a critical role in the mechanism of Na+ detection. However, the precise role of neurons in the detection of extracellular Na+ concentration ([Na+]out) remains unclear. Here we demonstrate that neurons of the median preoptic nucleus (MnPO), a structure in close contact with the CSF, are specific Na+ sensors. Electrophysiological recordings were performed on dissociated rat MnPO neurons under isotonic [Na+] (100 mM NaCl) with local application of hypernatriuric (150, 180 mM NaCl) or hyponatriuric (50 mM NaCl) external solution. The hyper- and hyponatriuric conditions triggered an in- and an outward current, respectively. The reversal potential of the current matched the equilibrium potential of Na+, indicating that a change in [Na+]out modified the influx of Na+ in the MnPO neurons. The conductance of the Na+ current was not affected by either the membrane potential or the [Na+]out. Moreover, the channel was highly selective for lithium over guanidinium. Together, these data identified the channel as a Na+ leak channel. A high correlation between the electrophysiological recordings and immunofluorescent labeling for the NaX channel in dissociated MnPO neurons strongly supports this channel as a candidate for the Na+ leak channel responsible for the Na+-sensing ability of rat MnPO neurons. The absence of NaX labeling and of a specific current evoked by a change in [Na+]out in mouse MnPO neurons suggests species specificity in the hypothalamus structures participating in central Na+ detection.

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