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The effect of head and body position on +Gz acceleration tolerance.
Aviat Space Environ Med. 1994 May; 65(5 Suppl):A90-4.AS

Abstract

It has been suggested there is a relationship between acceleration-induced loss of consciousness (G-LOC) and head/body position. A two-part investigation was conducted to determine whether head and body position affects acceleration tolerance. A retrospective analysis of high-G training data (N = 1,914) compared G-LOC occurrence during straight-ahead exposure to a "check-6" exposure [10 s at +9 Gz; 6 G/s onset rate; G-suit inflated; anti-G straining maneuver (AGSM) performed]. A prospective study (N = 12) was conducted with acceleration exposures using light loss criteria with subjects in straight-ahead, above, over-the-right shoulder, or over-the-left shoulder positions. Profiles consisted of 0.1 G/s onset-rate runs (no G-suit inflation; relaxed) to a maximum of +9 Gz and 0.5 G/s onset-rate runs (G-suit inflated; AGSM performed) to +9 Gz for up to 26 s. In the retrospective study, no significant difference existed between G-LOC occurrence during straight-ahead (22/1914) and check-6 (32/1914) positions. During the prospective study with AGSM runs, there was no significant difference in the time at maximum G among any of the positions. During the relaxed runs, several comparisons yielded significant differences in peak G attained. These results indicate there may be an underlying physiologic effect of head and body position on acceleration tolerance; however, the AGSM and the G-suit overcame this effect. Although task saturation and distraction may compromise performance of the AGSM and subsequently predispose acceleration-related hazards, a proper AGSM, combined with effective protective systems, remains essential components of a protection strategy.

Authors+Show Affiliations

Tong A
Combined Stress Branch, Armstrong Laboratory, Wright-Patterson AFB, OH.
Hill RC
No affiliation info available
Tripp L
No affiliation info available
Webb JT
No affiliation info available

MeSH

AccelerationAdultAerospace MedicineFemaleGravitationGravity SuitsHeadHumansMalePostureProspective StudiesRetrospective StudiesUnconsciousness

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

8018087

Citation

Tong, A, et al. "The Effect of Head and Body Position On +Gz Acceleration Tolerance." Aviation, Space, and Environmental Medicine, vol. 65, no. 5 Suppl, 1994, pp. A90-4.
Tong A, Hill RC, Tripp L, et al. The effect of head and body position on +Gz acceleration tolerance. Aviat Space Environ Med. 1994;65(5 Suppl):A90-4.
Tong, A., Hill, R. C., Tripp, L., & Webb, J. T. (1994). The effect of head and body position on +Gz acceleration tolerance. Aviation, Space, and Environmental Medicine, 65(5 Suppl), A90-4.
Tong A, et al. The Effect of Head and Body Position On +Gz Acceleration Tolerance. Aviat Space Environ Med. 1994;65(5 Suppl):A90-4. PubMed PMID: 8018087.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The effect of head and body position on +Gz acceleration tolerance. AU - Tong,A, AU - Hill,R C, AU - Tripp,L, AU - Webb,J T, PY - 1994/5/1/pubmed PY - 1994/5/1/medline PY - 1994/5/1/entrez SP - A90 EP - 4 JF - Aviation, space, and environmental medicine JO - Aviat Space Environ Med VL - 65 IS - 5 Suppl N2 - It has been suggested there is a relationship between acceleration-induced loss of consciousness (G-LOC) and head/body position. A two-part investigation was conducted to determine whether head and body position affects acceleration tolerance. A retrospective analysis of high-G training data (N = 1,914) compared G-LOC occurrence during straight-ahead exposure to a "check-6" exposure [10 s at +9 Gz; 6 G/s onset rate; G-suit inflated; anti-G straining maneuver (AGSM) performed]. A prospective study (N = 12) was conducted with acceleration exposures using light loss criteria with subjects in straight-ahead, above, over-the-right shoulder, or over-the-left shoulder positions. Profiles consisted of 0.1 G/s onset-rate runs (no G-suit inflation; relaxed) to a maximum of +9 Gz and 0.5 G/s onset-rate runs (G-suit inflated; AGSM performed) to +9 Gz for up to 26 s. In the retrospective study, no significant difference existed between G-LOC occurrence during straight-ahead (22/1914) and check-6 (32/1914) positions. During the prospective study with AGSM runs, there was no significant difference in the time at maximum G among any of the positions. During the relaxed runs, several comparisons yielded significant differences in peak G attained. These results indicate there may be an underlying physiologic effect of head and body position on acceleration tolerance; however, the AGSM and the G-suit overcame this effect. Although task saturation and distraction may compromise performance of the AGSM and subsequently predispose acceleration-related hazards, a proper AGSM, combined with effective protective systems, remains essential components of a protection strategy. SN - 0095-6562 UR - https://www.unboundmedicine.com/medline/citation/8018087/The_effect_of_head_and_body_position_on_+Gz_acceleration_tolerance_ L2 - https://medlineplus.gov/guidetogoodposture.html DB - PRIME DP - Unbound Medicine ER -