Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1981;320:253–268. doi: 10.1113/jphysiol.1981.sp013947

Load compensating responses of human abdominal muscles

R W Lansing 1, L Meyerink 1
PMCID: PMC1244045  PMID: 6459450

Abstract

1. We studied abdominal muscle responses to positive pressure loads applied suddenly to the external airway while subjects held a constant lung volume against steady pressure. The pre-loading holding pressure was 6 cm H2O, and the loading pressures were 6 or 12 cm H2O lasting for 2 sec.

2. Surface electromyograms (e.m.g.) were recorded over the internal oblique, external oblique, and rectus abdominis muscles. The latency and pattern of the e.m.g. reactions were studied by measuring the raw record for each loading trial, and by averaging the rectified e.m.g. for many trials.

3. No responses were obtained if subjects were instructed not to respond to the loads. When instructed and trained to maintain their pre-load position in spite of the load, a two-phase compensatory response was found. The initial response (phase I) was 100-300 msec in duration; it was followed by a continuous e.m.g. discharge (phase II) which continued to the offset of the pressure load. Subjects were also trained to make a single respiratory effort as quickly as possible after the load onset or after just an auditory stimulus. These were simple reaction time tasks of a traditional kind and the e.m.g. responses elicited were single, brief bursts.

4. For all subjects and experimental conditions the e.m.g. response of the internal oblique occurred first, followed by the external oblique and then the rectus abdominis. For the `maintain position' task, phase I latencies (internal oblique) averaged 66-90 msec for individual subjects, but for single trials with optimal conditions of practice and preparatory intervals these ranged from 42 to 110 msec with a third of the reactions occurring within 50-60 msec.

5. The latencies for reaction time responses to loading were about 6 msec shorter than the phase I latencies. The latency distributions for the two types of responses were similar, and both were affected to the same degree by practice, and changing the length and variability of the preparatory interval. Because of these similarities we suggest that the phase I reaction was a learned response of a `simple reaction time' type, and not comparable to late stretch reflexes such as the M2 of limb muscles.

6. Arm muscle responses to respiratory pressure changes were measured in three subjects under identical conditions used to obtain load reaction times of abdominal muscles. These simple reaction times averaged 61-71 msec, and ranged from 42 to 97 msec. Therefore very short proprioceptive reaction times are not peculiar to the respiratory system, or to load perturbations of the responding muscle.

7. Mechanical adjustments of airway pressure and lung volume in response to loading are first expressed at the mouth about 90 msec after abdominal muscle activity begins. In the `maintain position' task, the accuracy with which pressure and volume adjustments were made during the last 1.5 sec of the loading period approximated that reported in the literature for trained singers holding a tone using constant expiratory pressure.

Full text

PDF
253

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bouhuys A., Proctor D. F., Mead J. Kinetic aspects of singing. J Appl Physiol. 1966 Mar;21(2):483–496. doi: 10.1152/jappl.1966.21.2.483. [DOI] [PubMed] [Google Scholar]
  2. CAMPBELL E. J. M., GREEN J. H. The expiratory function of the abdominal muscles in man; an electromyographic study. J Physiol. 1953 May 28;120(3):409–418. doi: 10.1113/jphysiol.1953.sp004903. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Crago P. E., Houk J. C., Hasan Z. Regulatory actions of human stretch reflex. J Neurophysiol. 1976 Sep;39(5):925–935. doi: 10.1152/jn.1976.39.5.925. [DOI] [PubMed] [Google Scholar]
  4. DRAPER M. H., LADEFOGED P., WHITTERIDGE D. Expiratory pressures and air flow during speech. Br Med J. 1960 Jun 18;1(5189):1837–1843. doi: 10.1136/bmj.1.5189.1837. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. DRAPER M. H., LADEFOGED P., WHITTERIDGE D. Respiratory muscles in speech. J Speech Hear Res. 1959 Mar;2(1):16–27. doi: 10.1044/jshr.0201.16. [DOI] [PubMed] [Google Scholar]
  6. Davis J. N., Sears T. A. The proprioceptive reflex control of the intercostal muscles during their voluntary activation. J Physiol. 1970 Aug;209(3):711–738. doi: 10.1113/jphysiol.1970.sp009188. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Evarts E. V., Granit R. Relations of reflexes and intended movements. Prog Brain Res. 1976;44:1–14. doi: 10.1016/S0079-6123(08)60719-0. [DOI] [PubMed] [Google Scholar]
  8. Evarts E. V., Tanji J. Gating of motor cortex reflexes by prior instruction. Brain Res. 1974 May 17;71(2-3):479–494. doi: 10.1016/0006-8993(74)90992-5. [DOI] [PubMed] [Google Scholar]
  9. FLOYD W. F., SILVER P. H. S. Electromyographic study of patterns of activity of the anterior abdominal wall muscles in man. J Anat. 1950 Apr;84(2):132–145. [PMC free article] [PubMed] [Google Scholar]
  10. HAMMOND P. H. Involuntary activity in biceps following the sudden application of velocity to the abducted forearm. J Physiol. 1955 Feb 28;127(2):23–5P. [PMC free article] [PubMed] [Google Scholar]
  11. HAMMOND P. H. The influence of prior instruction to the subject on an apparently involuntary neuro-muscular response. J Physiol. 1956 Apr 27;132(1):17–8P. [PubMed] [Google Scholar]
  12. HOSHIKO M. S. Sequence of action of breathing muscles during speech. J Speech Hear Res. 1960 Sep;3:291–297. doi: 10.1044/jshr.0303.291. [DOI] [PubMed] [Google Scholar]
  13. KLEMMER E. T. Time uncertainty in simple reaction time. J Exp Psychol. 1956 Mar;51(3):179–184. doi: 10.1037/h0042317. [DOI] [PubMed] [Google Scholar]
  14. KUGELBERG E., HAGBARTH K. E. Spinal mechanism of the abdominal and erector spinae skin reflexes. Brain. 1958 Sep;81(3):290–304. doi: 10.1093/brain/81.3.290. [DOI] [PubMed] [Google Scholar]
  15. Lee R. G., Tatton W. G. Motor responses to sudden limb displacements in primates with specific CNS lesions and in human patients with motor system disorders. Can J Neurol Sci. 1975 Aug;2(3):285–293. doi: 10.1017/s0317167100020382. [DOI] [PubMed] [Google Scholar]
  16. Marsden C. D., Merton P. A., Morton H. B. Servo action in human voluntary movement. Nature. 1972 Jul 21;238(5360):140–143. doi: 10.1038/238140a0. [DOI] [PubMed] [Google Scholar]
  17. Marsden C. D., Merton P. A., Morton H. B. Servo action in the human thumb. J Physiol. 1976 May;257(1):1–44. doi: 10.1113/jphysiol.1976.sp011354. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES