Inspiratory muscle activity during unloaded and obstructed rebreathing in dogs

1988 ◽  
Vol 64 (1) ◽  
pp. 90-101 ◽  
Author(s):  
E. D'Angelo ◽  
N. Garzaniti ◽  
F. Bellemare
Keyword(s):  
Muscle Activity ◽  
Moving Average ◽  
Inspiratory Muscle ◽  
Central Control ◽  
Control Mechanisms ◽  
Peak Activity ◽  
Airway Occlusion ◽  
Inspiratory Muscles ◽  
Thoracic Muscles ◽  
Proprioceptive Inputs

Moving-average electromyogram (EMG) of the diaphragm (DI), scalenes, and cranial and caudal parasternals was assessed in anesthetized, supine, and head-up dogs during rebreathing. The shape of EMG trajectory was similar for all muscles and conditions; activation of different muscles could be thus compared on the basis of changes in peak activity. In intact dogs changes in peak activity were greater for the scalenes and cranial parasternals than for the caudal parasternals and greater for the inspiratory thoracic muscles (ITM) than for the DI. Posture, vagotomy, and cordotomy at C7-T1 did not affect the rate of rise of DI activity. The relations between peak activity of ITM did not change because of posture, vagotomy, and phrenicotomy. Vagotomy selectively depressed the rate of rise of ITM activity, but relative changes in peak ITM activity for a given change in peak DI activity were independent of intact vagi. Differences in the pattern of activation between inspiratory muscles with rebreathing are largely independent of proprioceptive inputs and likely reflect properties of central control mechanisms. However, airway occlusion at end expiration caused a reflex fall of DI activity and reflex increase of ITM activity in intact and vagotomized dogs. Cordotomy at C7-T1 did not change DI response, whereas reduction of ITM activity occurred after phrenicotomy, indicating that both facilitatory and inhibitory segmental inputs are involved in ITM response to loading.

scholarly journals Performance Evaluation of Fixed Sample Entropy in Myographic Signals for Inspiratory Muscle Activity Estimation

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 183 ◽  
Author(s):  
Manuel Lozano-García ◽  
Luis Estrada ◽  
Raimon Jané
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Cardiac Activity ◽  
Sample Entropy ◽  
Inspiratory Muscle ◽  
Chronic Obstructive ◽  
Inspiratory Muscles ◽  
Fixed Sample ◽  
Cross Covariance ◽  
Activity Estimation

Fixed sample entropy (fSampEn) has been successfully applied to myographic signals for inspiratory muscle activity estimation, attenuating interference from cardiac activity. However, several values have been suggested for fSampEn parameters depending on the application, and there is no consensus standard for optimum values. This study aimed to perform a thorough evaluation of the performance of the most relevant fSampEn parameters in myographic respiratory signals, and to propose, for the first time, a set of optimal general fSampEn parameters for a proper estimation of inspiratory muscle activity. Different combinations of fSampEn parameters were used to calculate fSampEn in both non-invasive and the gold standard invasive myographic respiratory signals. All signals were recorded in a heterogeneous population of healthy subjects and chronic obstructive pulmonary disease patients during loaded breathing, thus allowing the performance of fSampEn to be evaluated for a variety of inspiratory muscle activation levels. The performance of fSampEn was assessed by means of the cross-covariance of fSampEn time-series and both mouth and transdiaphragmatic pressures generated by inspiratory muscles. A set of optimal general fSampEn parameters was proposed, allowing fSampEn of different subjects to be compared and contributing to improving the assessment of inspiratory muscle activity in health and disease.

scholarly journals Effects of Inspiratory Muscles Training Plus Rib Cage Mobilization on Chest Expansion, Inspiratory Accessory Muscles Activity and Pulmonary Function in Stroke Patients

2020 ◽  
Vol 10 (15) ◽  
pp. 5178
Author(s):  
Shin Jun Park
Keyword(s):  
Pulmonary Function ◽  
Muscle Activity ◽  
Inspiratory Muscle ◽  
Inspiratory Muscle Training ◽  
Control Group ◽  
Muscle Training ◽  
Rib Cage ◽  
Joint Mobilization ◽  
Chest Expansion ◽  
Inspiratory Muscles

After stroke, limited ribcage movement may lead to impaired respiratory function. Combining threshold inspiratory muscle training with rib cage joint mobilization has been shown to enhance the recovery of respiratory function in patients with stroke. The present study investigated whether the combination of rib cage joint mobilization and inspiratory muscle training would improve chest expansion, inspiratory muscle activity, and pulmonary function after stroke. Thirty stroke patients were recruited and randomly assigned to one of the two groups, namely 6-week rib cage joint mobilization with inspiratory muscle training (experimental group) or inspiratory muscle training alone (control group). Outcome measures included upper and lower chest expansion, activity of accessory inspiratory muscles (latissimus dorsi (LD) and upper trapezius (UT)), and pulmonary function (forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and peak expiratory flow (PEF)). All evaluations were conducted at baseline and after 6 weeks of inspiratory muscle training. Significant increases were observed in upper and lower chest expansion, LD and UT muscle activity, FVC, FEV1, and PEF in both the groups. Upper and lower chest expansion and muscle activity of UT and LD were significantly higher in the experimental group than in the control group. No significant differences were observed in FVC, FEV1, and PEF between the groups. Inspiratory muscle training is effective in improving chest expansion, inspiratory muscle activity, and pulmonary function after stroke. The addition of rib cage joint mobilization further increases chest expansion and inspiratory muscle activity.

Breathing in Singing

2014 ◽  
pp. 86-108
Author(s):  
Alan Watson
Keyword(s):  
Abdominal Wall ◽  
Muscle Activity ◽  
Abdominal Muscle ◽  
Inspiratory Muscle ◽  
Lung Volumes ◽  
Inspiratory Muscles

Accounts of breathing in methodological books on singing are often confusing or inaccurate rather than helpful. This chapter provides an overview of the principles ofrespiration and how this is modified for singing. Inspiration results from an increase inthoracic dimensions caused by activity in the diaphragm and external intercostal muscles.At high lung volumes the sternocleidomastoids and scalenes also aid chest expansion.Subglottic pressure is created during expiration by the contraction of the abdominal wall,predominantly as a result of lateral abdominal muscle activity, which drives the relaxeddiaphragm upwards while simultaneously the internal intercostals pull the ribsdownwards. When the lungs are full and the inspiratory muscles release, elastic recoilforces alone can drive out the air and in order to regulate subglottic pressure theseforces must be resisted by gradually reducing inspiratory muscle activity. How different patterns of activity in these and other muscles contribute to singing is described and theway in which similar ends can be achieved by different means in different singers isexplained.

Selective activation of quadriceps muscle fibers according to bicycling rate

1984 ◽  
Vol 57 (2) ◽  
pp. 371-379 ◽  
Author(s):  
G. Citterio ◽  
E. Agostoni
Keyword(s):  
Muscle Activity ◽  
Peak Power ◽  
Moving Average ◽  
Quadriceps Muscle ◽  
Velocity Curve ◽  
Movement Speed ◽  
Selective Activation ◽  
Muscle Properties ◽  
Inspiratory Muscles ◽  
Constant Rate

Moving average electromyography (MA) of quadriceps muscle bellies has been recorded during bicycling at different rates (30–70 cycles/min) or forces (1–3 kg). For power increments (50–100%) achieved by increasing force at constant rate, MA during pedal downstroke always increased. For similar power increments achieved by increasing the rate at constant force, MA did not increase (37% of cases), increased less (37%), or increased similarly (26%). Investigations by others on the rat suggest that the lack of increase of MA despite power increment was not compensated by other muscle activity; hence it indicates a shift from slow to fast fibers, which provide greater power per unit stimulus. Smaller increase of MA with increasing rate rather than force at isopower could depend on this shift or on muscle properties, if operating on ascending limb of power-velocity curve. This, however, does not seem the case for slow fibers, which should develop peak power at about 25 cycles/min. Hence, fibers of quadriceps muscle of humans seem selectively activated according to movement speed, as previously found in inspiratory muscles of rabbits.

Tonic inspiratory muscle activity as a cause of hyperinflation in asthma

1981 ◽  
Vol 50 (2) ◽  
pp. 279-282 ◽  
Author(s):  
N. Muller ◽  
A. C. Bryan ◽  
N. Zamel
Keyword(s):  
Muscle Activity ◽  
Inspiratory Muscle ◽  
Tonic Activity ◽  
Surface Electrodes ◽  
Inspiratory Muscles ◽  
Thoracic Gas Volume ◽  
Before And After ◽  
Male Patients ◽  
Gas Volume ◽  
Proportional Reduction

We studied tonic activity of the inspiratory muscles during exacerbation of asthma in five female and two male patients. Exacerbation was provoked by withholding bronchodilatory medication for 12 h prior to the study. Thoracic gas volume (TGV) at the end of resting expiration was determined before and after albuterol (salbutamol) inhalation with a body plethysmograph. Intercostal muscle electromyogram (EMG) was recorded with surface electrodes and diaphragmatic EMG with esophageal electrodes. Tonic activity was defined as electrical activity in the EMG present throughout expiration. After salbutamol the TGV decreased 13.4 +/- 2.9% (mean +/- SE) (P less than 0.01). This decrease in TGV was accompanied by a proportional reduction in tonic intercostal (r = 0.78, P less than 0.05) and diaphragmatic activity (r = 0.84, P less than 0.05). These findings suggest that the hyperinflation present during exacerbation of asthma is at least in part due to active inspiratory muscle activity present throughout expiration.

Tonic inspiratory muscle activity as a cause of hyperinflation in histamine-induced asthma

1980 ◽  
Vol 49 (5) ◽  
pp. 869-874 ◽  
Author(s):  
N. Muller ◽  
A. C. Bryan ◽  
N. Zamel
Keyword(s):  
Lung Volume ◽  
Muscle Activity ◽  
Normal Subjects ◽  
Inspiratory Muscle ◽  
Intercostal Muscle ◽  
Tonic Activity ◽  
Surface Electrodes ◽  
Inspiratory Muscles ◽  
Thoracic Gas Volume ◽  
Gas Volume

We studied the change in tonic activity of the inspiratory muscles during acute hyperinflation. Hyperinflation was provoked in two asthmatic and three normal subjects by progressively doubling doses of histamine. Changes in lung volume were determined with magnetometers and with a body plethysmograph. Intercostal muscle activity was recorded with surface electrodes and diaphragmatic activity with esophageal electrodes. Tonic activity was defined as electrical activity in the electromyogram present at end expiration. After histamine the maximal observed increase in plethysmographic thoracic gas volume in the five subjects was 29.8 +/- 6.4% of control (mean +/- SE). Hyperinflation was accompanied by a significant increase in tonic activity of the intercostal muscles (P < 0.01) and the diaphragm (P < 0.01). There was a significant correlation between the increase in thoracic gas volume and the increase in tonic intercostal (r = 0.82, P = 0.003) and diaphragmatic (r = 0.89, P = 0.003) activity. We conclude that histamine-induced hyperinflation is accompanied by persistent inspiratory muscle activity throughout expiration.

Relation Between Inspiratory Muscle Strength and Recruitment Onset of Neck Inspiratory Muscles

2017 ◽  
Vol 49 (5S) ◽  
pp. 798
Author(s):  
Sohei Washino ◽  
Hironori Watanabe ◽  
Hiroaki Kanehisa ◽  
Yasuhide Yoshitake
Keyword(s):  
Muscle Strength ◽  
Inspiratory Muscle ◽  
Inspiratory Muscles ◽  
Inspiratory Muscle Strength

Effect of hypoxia on the pressure developed by inspiratory muscles during airway occlusion

1976 ◽  
Vol 40 (3) ◽  
pp. 372-378 ◽  
Author(s):  
S. G. Kelsen ◽  
M. D. Altose ◽  
N. N. Stanley ◽  
R. S. Levinson ◽  
N. S. Cherniack ◽  
...  
Keyword(s):  
Pressure Response ◽  
Occlusion Pressure ◽  
Airway Occlusion ◽  
Single Breath ◽  
Inspiratory Muscles ◽  
Resistive Loading ◽  
Expired Gas ◽  
Motoneuron Activity ◽  
Maximal Pressure ◽  
Ventilatory Response To Hypoxia

The effect of progressive isocapnic hypoxia on the pressure generated by the inspiratory muscle during airway occlusion was studied in 10 awake subjects during normal and obstructed breathing. Isocapnic hypoxia was produced by rebreathing a gas mixture of 6% CO2 in air while the expired gas was passed through a CO2 scrubber so as to maintain PACO2 constant (42.6 mmHg +/- 2.2 SE). Occlusion of the airway was performed randomly for a single breath at FRC. In all 10 subjects maximal pressure (Ppeak) and the pressures measured 100, 200, 300, and 400 ms after the onset of inspiration increased during hypoxia. Furthermore, good correlation was noted between the occlusion pressure response to hypoxia (delta P/DELTA[1/PO2-32]) and simultaneous changes in ventilatory response to hypoxia (delta VI/DELTA[1/PO2-32]). The occlusion pressure response to hypoxia therefore seems to be a reliable measure of respiratory center output. When rebreathing was repeated during inspiratory resistive loading, the occlusion pressure at any given PO2 and delta P/DELTA(1PO2-32) measured in the first 400 ms of inspiration increased in 9 of 10 subjects. Since PACO2 and PAO2 during both control and loaded experiments were the same, the increase in occlusion pressure in the presence of flow-resistive loading appeared to represent a neurally mediated increase in inspiratory motoneuron activity.

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