King's College London

Introduction: Physical conditioning may improve aircrew performance during exposure to high +G _z acceleration, although few studies have directly assessed this. The present study investigated the effects of a 12-wk Aircrew Conditioning Programme (ACP) on markers of G tolerance. The ACP comprises aerobic and muscle strengthening exercise performed twice weekly and targets improved fitness and reduced injury risk. Methods: There were 36 UK Royal Air Force and Royal Navy aircrew who volunteered; 17 performed the ACP (Ex) and 19 acted as a control group (Con). Centrifuge testing was performed before and after the intervention. Relaxed G tolerance (RGT) and straining G tolerance (SGT), which had the addition of muscle tensing, were assessed. G endurance was also determined via repeated simulated air combat maneuvers (SACMs). During these centrifuge runs a number of physiological variables were recorded. Results: During the G profile to determine RGT, neither RGT, HR, nor blood pressure responses were affected by the ACP. During SGT profiles, a lower HR at a given +G _z (+5.5 G _z) level following the ACP was observed (Ex: pre 146.0 ± 4.4, post 136.9 ± 5.6 bpm; Con: pre 148.0 ± 3.2, post 153.1 ± 3.3 bpm). BP was maintained and there was a tendency toward an improved SGT. The ACP increased the proportion of individuals completing the number of SACM profiles, although no meaningful differences were found between groups in other variables. Conclusion: Overall the ACP has no negative effect on RGT, reduced the physiological strain associated with a given level of +G _z (during SGT), and tended to improve the ability to tolerate repeated G _z exposure.