The Relationship between Changes in Arterial Pressure, Esophageal Pressure and the EMG (Electromyography) of Various Muscle Groups during the L-1 Straining Maneuver at Different Spine-to-Thigh Angles
Abstract
Changes in arterial blood pressure, intrathoracic pressure, heart rate, and the electromyographic activity of various muscle groups were determined while 9 male subjects performed L-1 straining maneuvers at four spine-to-thigh angles (70, 84, 94, and 105 deg). There was no significant difference between the changes in these physiological variables due to the different angles. At the onset of the L-1, arterial pressure immediately increased to an average of 195 mm Hg but fell progressively during the next 5 sec of the maneuver, to 160 mm Hg. Arterial pressure remained at this level during the middle part of the L-1 and then recovered to 179 mm Hg by the end of the maneuver. Esophageal pressure followed essentially the same pattern of response, but heart rate progressively increased during the L-1. Electromyographic activity of all the muscle groups tested increased immediately at the onset of the straining, and then remained constant for the duration of the L-1. No one muscle group was utilized more than another. Inflation of an anti-G suit to 4 PSI had no effect on the variables measured. Keywords: Gravity tolerance, Flight simulation, Stress (Physiology).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1987
- Accession Number
- ADA196690
Entities
People
- A. Karl
- Carole A. Williams
- Gary W. Miller
- J. E. Douglas
- R. L. Wiley