Abstract： Objective To investigate the change features in the physical performance of helicopter aviators who stayed onboard for a prolonged time,to develop schemes of physical performance training directed at shipboard helicopter aviators and finally to analyze and assess the effects of the intervention schemes,through detection of physical performance parameters of the aviators at different stages of deployment.Methods Fiftyeight helicopter aviators from different batches of escort personnel in the Gulf of Aden were selected as our research subjects.Bilateral gripping power,lumboabdominal muscle strength,PWC170,amplitude of variations in body mass index (BMI),fat percentage and weight were measured or tested at different stages of deployment both before and after physical performance training.Changes in physical performance induced by prolonged stay onboard the ship and the effects of training intervention were discussed in detail,through comparisons of self control and parallel control between groups.Results Before enforcement of physical performance training intervention,bilateral gripping power of the aviators detected at d 48 all decreased by 25％ (left:28.6 ± 5.67 ;right:33.55 ± 6.82),then kept at a relatively lower level till day 71 (left:28.88 ± 4.68; right:32.45 ± 5.55).This trend of decrease by about 5-7％ continued all the way till day 92 (left:26.57 ± 6.74,fight:31.63±6.00).Statistical significance could be noted,when the decreased levels were compared with those before they deployed onboard ships (left:39.94 ± 5.76 ; right:43.04 ± 4.75) (P ＜ 0.05).In total,the decrease in physical performance was as high as 33％.When they returned to their organic units,scores of push-ups and sit-ups were obviously decreased (19.15 ± 3.75,19.0 ± 6.6),and statistical significance could be found,when they were compared with those before deployment (24.65 ± 3.3,23.8 ± 5.9) (P ＜ 0.05).Amplitude of variations in body mass and BMI for the shipboard aviators (3.30 ± 3.01,1.08 ± 0.99) was obviously higher,when it was compared with those of the onshore control group(0.55 ±0.55,0.14 ±0.16) (P＜0.01).Following physical performance training intervention,bilateral gripping power at d 48 (left:38.56 ± 6.06,right:42.28 ± 6.50)were decreased by only 5 ～ 7％,then displayed a slow ascending trend.At day 92,no statistical significance could be seen in physical performance (left:42.28 ± 6.50; right:45.44 ± 4.96),when compared with those before they stayed onboard (P ＞ 0.05).When they were compared with those of the onshore control group,no statistical differences could be noted in the indices of lumboabdominal muscle strength,PWC170,BMI and fat percentage for the shipboard aviators both before and after deployment(P ＞ 0.05).Conclusions The physical performance training scheme could produce good effects on the reduction of physical performance in shipboard aviators,during their prolonged deployment at sea.Due to the fact that significant decrease in physical performance occurred at the end of the first month deployment,physical performance training intervention should be started immediately after they came onboard,not later than one month.