Activation of the human diaphragm during a repetitive postural task

Hodges, PW and Gandevia, SC (2000) Activation of the human diaphragm during a repetitive postural task. Journal of Physiology-london, 522 1: 165-175. doi:10.1111/j.1469-7793.2000.t01-1-00165.xm


Author Hodges, PW
Gandevia, SC
Title Activation of the human diaphragm during a repetitive postural task
Journal name Journal of Physiology-london   Check publisher's open access policy
ISSN 0022-3751
Publication date 2000-01-01
Year available 2000
Sub-type Article (original research)
DOI 10.1111/j.1469-7793.2000.t01-1-00165.xm
Open Access Status DOI
Volume 522
Issue 1
Start page 165
End page 175
Total pages 11
Place of publication NEW YORK
Publisher CAMBRIDGE UNIV PRESS
Language eng
Abstract 1. The co-ordination between respiratory and postural functions of the diaphragm was investigated during repetitive upper Limb movement. It was hypothesised that diaphragm activity would occur either tonically or phasically in association with the forces from each movement and that this activity would combine with phasic respiratory activity. 2. Movements of the upper limb and ribcage were measured while standing subjects performed repetitive upper limb movements 'as fast as possible'. Electromyographic (EMG) recordings of the costal diaphragm were made using intramuscular electrodes in four subjects. Surface electrodes were placed over the deltoid and erector spinae muscles. 3. In contrast to standing at rest, diaphragm activity was present throughout expiration at 78 +/- 17% (mean +/- S.D.) of its peak inspiratory magnitude during repeated upper limb movement. 4. Bursts of deltoid and erector spinae EMG activity occurred at the Limb movement frequency (similar to 2.9 Hz). Although the majority of diaphragm EMG power was at the respiratory frequency (similar to 0.4 Hz), a peak was also present at the movement frequency. This finding was corroborated by averaged EMG activity triggered from upper limb movement. In addition, diaphragm EMG activity was coherent with ribcage motion at the respiratory frequency and with upper limb movement at the movement frequency. 5. The diaphragm response was similar when movement was performed while sitting. In addition, when subjects moved with increasing frequency the peak upper limb acceleration correlated with diaphragm EMG amplitude. These findings support the argument that diaphragm contraction is related to trunk control. 6. The results indicate that activity of human phrenic motoneurones is organised such that it contributes to both posture and respiration during a task which repetitively challenges trunk posture.
Keyword Physiology
Intra-abdominal Pressure
Voluntary Arm Movements
Trunk Muscle-activity
Intraabdominal Pressure
Adjustments
Contraction
Receptors
Responses
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Health and Rehabilitation Sciences Publications
 
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Created: Mon, 13 Aug 2007, 21:34:18 EST