The development and evaluation of a structured conditioning programme on physiological performance under conditions of high +Gz

Student thesis: Doctoral ThesisDoctor of Philosophy


There remains concern over the ability of aviators to tolerate the considerable +Gz stressors of the modern high performance aviation environment. The aim of this thesis was to further understand the present status of +Gz related incidents in the Royal Air Force (RAF), to design and construct validate a physical conditioning programme, then test its efficacy on performance under high +Gz. A survey was conducted asking 2351 aircrew (1878 pilots, 473 weapon systems operators) to describe details of G-induced loss of consciousness (G-LOC) and almost loss of consciousness (A-LOC) events. The results revealed that the prevalence of reported +Gz related incidents in the RAF remains a hazard to all aircrew with 14.8% reporting a G-LOC and 32.2% reporting an A-LOC event at some point in their flying career. Student aircrew reported a higher incidence of both events, presumably due to their relative inexperience in both +Gz awareness and ability to perform an effective anti- G straining manoeuvre (AGSM). An Aircrew Conditioning Programme (ACP) was developed which incorporated exercises designed to enhance performance through improvements in the ability to repeatedly perform an AGSM and subjected to construct validity by a panel of experts. The ACP demonstrated excellent content validity for the individual exercise sessions and for the overall programme in terms of relevance and simplicity for delivery to the aircrew population. A controlled trial was undertaken into order to test the efficacy of the ACP (n=16 ACP, and 19 controls) took part in a 12 week programme after which performance on the man carrying centrifuge under high +Gz was assessed. The ACP did not negatively affect relaxed or straining +Gz-level tolerance (SGT). However, during the +5.5 Gz SGT step a lower physiological strain was indicated in the ACP group by a lower heart rate for the equivalent load (pre 146.0 ± 4.4, post 136.9 ± 5.6 beats.min-1) compared with the Control group (pre 148.0 ± 3.2, post 153.1 ± 3.3 beats.min-1), while mean arterial blood pressure was unchanged. During the simulated air combat manoeuvre runs the number of +7 Gz peaks completed by each subject (maximum of 16) had a tendency to increase in the ACP group only (pre 14.0 ± 1.2, post 15.4 ± 0.4) whereas the control group had a tendency to reduce (pre 14.0 ± 0.9, post 13.6 ± 1.1). Overall the data in this thesis suggest that G-LOC remains a significant issue among fast jet air crew and that the use of an ACP may help to ameliorate physiological challenges faced under high Gz.
Date of Award1 Dec 2018
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorStephen Harridge (Supervisor) & Dianne Newham (Supervisor)

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