Fang Liu , Alice Y.M. Jones , Raymond C.C. Tsang , Timothy T.T. Yam , William W.N. Tsang
{"title":"健康年轻人在吸气压力负荷增加时横膈膜和胸锁乳突肌的募集。","authors":"Fang Liu , Alice Y.M. Jones , Raymond C.C. Tsang , Timothy T.T. Yam , William W.N. Tsang","doi":"10.1016/j.resp.2024.104365","DOIUrl":null,"url":null,"abstract":"<div><h3>Background</h3><div>Inspiratory muscle training (IMT) is often employed to enhance improvement in inspiratory muscle strength. However, the relationship between inspiratory muscle recruitment patterns and increasing inspiratory load remains unclear. Furthermore, the effect of breathing instructions on diaphragm activity at various inspiratory loads is unknown.</div></div><div><h3>Objective</h3><div>To investigate the recruitment activity of the diaphragm and sternocleidomastoid (SCM) muscle under increased inspiratory pressure loading, with and without diaphragmatic breathing instructions, in healthy young adults.</div></div><div><h3>Methods</h3><div>Participants were invited to breathe, in random order, 6 sets of 10 breaths at inspiratory loads of 30 % to 80 % maximal inspiratory pressure (MIP), in 10 % increments. The measurement process was repeated with a specific focus of diaphragmatic descent during inspiration. During each targeted breath, recordings of surface electromyography of the right SCM muscle and thickness of the right hemi-diaphragm measured by ultrasonography were undertaken concurrently.</div></div><div><h3>Results</h3><div>Sixty-two adults (31 males, age: 23±3 years) participated in the study. Irrespective of breathing instructions, computed diaphragm thickening fraction (DTf) increased with increasing inspiratory load but peaked at 50 % MIP and declined with increasing load to 80 % MIP. SCM recruitment increased with increasing inspiratory load to 80 % MIP. Forced inspiration with diaphragmatic breathing was associated with a higher DTf and lower SCM muscle activity. The above pattern was similar for both male and female participants. Female participants produced higher SCM activity compared with males but only at inspiration loads below 50 % MIP.</div></div><div><h3>Conclusions</h3><div>In a cohort of young healthy adults, magnitude of diaphragmatic effort was greatest at 50 % MIP but declined with increasing inspiratory load to 80 % MIP. Forced inspiration combined with focused diaphragmatic breathing accentuated diaphragm contraction and reduced SCM muscle contribution. Our findings show that diaphragmatic muscle recruitment is non-linear and that the generic clinical prescription of an IMT program may need to be reconfigured.</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104365"},"PeriodicalIF":1.9000,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Recruitment of the diaphragm and sternocleidomastoid muscle during increasing inspiratory pressure loads in healthy young adults\",\"authors\":\"Fang Liu , Alice Y.M. Jones , Raymond C.C. Tsang , Timothy T.T. Yam , William W.N. Tsang\",\"doi\":\"10.1016/j.resp.2024.104365\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><h3>Background</h3><div>Inspiratory muscle training (IMT) is often employed to enhance improvement in inspiratory muscle strength. However, the relationship between inspiratory muscle recruitment patterns and increasing inspiratory load remains unclear. Furthermore, the effect of breathing instructions on diaphragm activity at various inspiratory loads is unknown.</div></div><div><h3>Objective</h3><div>To investigate the recruitment activity of the diaphragm and sternocleidomastoid (SCM) muscle under increased inspiratory pressure loading, with and without diaphragmatic breathing instructions, in healthy young adults.</div></div><div><h3>Methods</h3><div>Participants were invited to breathe, in random order, 6 sets of 10 breaths at inspiratory loads of 30 % to 80 % maximal inspiratory pressure (MIP), in 10 % increments. The measurement process was repeated with a specific focus of diaphragmatic descent during inspiration. During each targeted breath, recordings of surface electromyography of the right SCM muscle and thickness of the right hemi-diaphragm measured by ultrasonography were undertaken concurrently.</div></div><div><h3>Results</h3><div>Sixty-two adults (31 males, age: 23±3 years) participated in the study. Irrespective of breathing instructions, computed diaphragm thickening fraction (DTf) increased with increasing inspiratory load but peaked at 50 % MIP and declined with increasing load to 80 % MIP. SCM recruitment increased with increasing inspiratory load to 80 % MIP. Forced inspiration with diaphragmatic breathing was associated with a higher DTf and lower SCM muscle activity. The above pattern was similar for both male and female participants. Female participants produced higher SCM activity compared with males but only at inspiration loads below 50 % MIP.</div></div><div><h3>Conclusions</h3><div>In a cohort of young healthy adults, magnitude of diaphragmatic effort was greatest at 50 % MIP but declined with increasing inspiratory load to 80 % MIP. Forced inspiration combined with focused diaphragmatic breathing accentuated diaphragm contraction and reduced SCM muscle contribution. Our findings show that diaphragmatic muscle recruitment is non-linear and that the generic clinical prescription of an IMT program may need to be reconfigured.</div></div>\",\"PeriodicalId\":20961,\"journal\":{\"name\":\"Respiratory Physiology & Neurobiology\",\"volume\":\"331 \",\"pages\":\"Article 104365\"},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2024-11-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Respiratory Physiology & Neurobiology\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1569904824001587\",\"RegionNum\":4,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"PHYSIOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Respiratory Physiology & Neurobiology","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1569904824001587","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSIOLOGY","Score":null,"Total":0}
Recruitment of the diaphragm and sternocleidomastoid muscle during increasing inspiratory pressure loads in healthy young adults
Background
Inspiratory muscle training (IMT) is often employed to enhance improvement in inspiratory muscle strength. However, the relationship between inspiratory muscle recruitment patterns and increasing inspiratory load remains unclear. Furthermore, the effect of breathing instructions on diaphragm activity at various inspiratory loads is unknown.
Objective
To investigate the recruitment activity of the diaphragm and sternocleidomastoid (SCM) muscle under increased inspiratory pressure loading, with and without diaphragmatic breathing instructions, in healthy young adults.
Methods
Participants were invited to breathe, in random order, 6 sets of 10 breaths at inspiratory loads of 30 % to 80 % maximal inspiratory pressure (MIP), in 10 % increments. The measurement process was repeated with a specific focus of diaphragmatic descent during inspiration. During each targeted breath, recordings of surface electromyography of the right SCM muscle and thickness of the right hemi-diaphragm measured by ultrasonography were undertaken concurrently.
Results
Sixty-two adults (31 males, age: 23±3 years) participated in the study. Irrespective of breathing instructions, computed diaphragm thickening fraction (DTf) increased with increasing inspiratory load but peaked at 50 % MIP and declined with increasing load to 80 % MIP. SCM recruitment increased with increasing inspiratory load to 80 % MIP. Forced inspiration with diaphragmatic breathing was associated with a higher DTf and lower SCM muscle activity. The above pattern was similar for both male and female participants. Female participants produced higher SCM activity compared with males but only at inspiration loads below 50 % MIP.
Conclusions
In a cohort of young healthy adults, magnitude of diaphragmatic effort was greatest at 50 % MIP but declined with increasing inspiratory load to 80 % MIP. Forced inspiration combined with focused diaphragmatic breathing accentuated diaphragm contraction and reduced SCM muscle contribution. Our findings show that diaphragmatic muscle recruitment is non-linear and that the generic clinical prescription of an IMT program may need to be reconfigured.
期刊介绍:
Respiratory Physiology & Neurobiology (RESPNB) publishes original articles and invited reviews concerning physiology and pathophysiology of respiration in its broadest sense.
Although a special focus is on topics in neurobiology, high quality papers in respiratory molecular and cellular biology are also welcome, as are high-quality papers in traditional areas, such as:
-Mechanics of breathing-
Gas exchange and acid-base balance-
Respiration at rest and exercise-
Respiration in unusual conditions, like high or low pressure or changes of temperature, low ambient oxygen-
Embryonic and adult respiration-
Comparative respiratory physiology.
Papers on clinical aspects, original methods, as well as theoretical papers are also considered as long as they foster the understanding of respiratory physiology and pathophysiology.