Objective:To explore the relationship among maximal oxygen uptake (VO 2max), heart rate recovery after exercise (HRR) and anti-G ability of fighter pilots. Methods:A total of 90 fighter pilots were selected by cluster sampling method, and the +G z tolerance that devoted by anti-G staining manoeuvre performing was predicted by anti-G and anti-hypoxia ability detector and G tolerance empirical formula. The values of VO 2max and HRR were collected under 25 W/min power increasing rate scheme. According to the level of VO 2max, pilots were divided into 3 groups: low level (the bottom third), intermediate level (the middle third) and high level (the top third). The differences of HRR value and +G z tolerance increment among the first, second and third minutes after exercise were compared among the pilots of different level of VO 2max. The correlation among the values of HRR, VO 2max and +G z tolerance increment were analyzed. Results:There were significant differences in the values of HRR and +G z tolerance increment at the second and the third minutes of exercise among the pilots with different VO 2max levels in 3 groups ( F=7.65, 10.64, 10.28, all P≤0.001). There was no obvious correlation between the values of HRR, VO 2max and +G z tolerance increment at the first minute after exercise ( r=0.020, -0.017, P=0.852, 0.871). The value of HRR at the second minute after exercise was positively correlated with VO 2max ( r=0.288, P=0.006), but not obviously with the +G z tolerance increment ( r=-0.017, P=0.150). The value of HRR value at the third minute was positively correlated with the increase of VO 2max and +G z tolerance increment ( r=0.433, 0.240, P<0.001, =0.023). VO 2max was positively correlated with the increase of +G z tolerance increment ( r=0.436, P<0.001). Conclusions:The increase of pilots′ VO 2max is conducive to the improvement of anti-G ability. The value of HRR at the third minute after exercise can be used as a sensitive monitoring index to predict pilot′s G-tolerance.

Objective:To explore the relationship among maximal oxygen uptake (VO 2max), heart rate recovery after exercise (HRR) and anti-G ability of fighter pilots. Methods:A total of 90 fighter pilots were selected by cluster sampling method, and the +G z tolerance that devoted by anti-G staining manoeuvre performing was predicted by anti-G and anti-hypoxia ability detector and G tolerance empirical formula. The values of VO 2max and HRR were collected under 25 W/min power increasing rate scheme. According to the level of VO 2max, pilots were divided into 3 groups: low level (the bottom third), intermediate level (the middle third) and high level (the top third). The differences of HRR value and +G z tolerance increment among the first, second and third minutes after exercise were compared among the pilots of different level of VO 2max. The correlation among the values of HRR, VO 2max and +G z tolerance increment were analyzed. Results:There were significant differences in the values of HRR and +G z tolerance increment at the second and the third minutes of exercise among the pilots with different VO 2max levels in 3 groups ( F=7.65, 10.64, 10.28, all P≤0.001). There was no obvious correlation between the values of HRR, VO 2max and +G z tolerance increment at the first minute after exercise ( r=0.020, -0.017, P=0.852, 0.871). The value of HRR at the second minute after exercise was positively correlated with VO 2max ( r=0.288, P=0.006), but not obviously with the +G z tolerance increment ( r=-0.017, P=0.150). The value of HRR value at the third minute was positively correlated with the increase of VO 2max and +G z tolerance increment ( r=0.433, 0.240, P<0.001, =0.023). VO 2max was positively correlated with the increase of +G z tolerance increment ( r=0.436, P<0.001). Conclusions:The increase of pilots′ VO 2max is conducive to the improvement of anti-G ability. The value of HRR at the third minute after exercise can be used as a sensitive monitoring index to predict pilot′s G-tolerance.

Objective To evaluate the clinical results of free vascularized fibular grafting (FVFG) for the treatment of osteonecrosis of the femoral head (ONFH).Methods From July,2009 to January,2013,85 cases (120 hips) of ONFH were treated with free vascularized fibular grafting.These cases included 61 males (87 hips) and 24 females (33 hips) with an average age of 36.5 years (22-51 years);7 hips (Ⅰ A 2 hips,Ⅰ B 3 hips,Ⅰ C 2 hips) were at stage Ⅰ,98 hips (Ⅱ A 24 hips,ⅡB 39 hips,ⅡC 35 hips) at stage Ⅱ and 15 hips (ⅢA 9 hips,ⅢB 4 hips,Ⅱ C 2 hips) at stage]Ⅲ according to the classification system of Association Research Circulation Osseous (ARCO).The mean preoperative Harris hip score was (60.21±6.85) points (42-71 points),The follow-up items included the X-ray examination,the Harris scores of the hip,and the evaluation of the complications.Results Eighty-three cases (117 hips) were followed up.The average duration of follow-up was 25 months (range from 12 months to 42 months).The mean postoperative Harris hip score was increased to (81.26±5.84) points (67-91 points) by the end of the follow-up,compared with the preoperation,the score improved significantly,the difference was statistically significant (P＜0.05).Comparing with postoperative X-ray,101 hips (86.3％) were improved,12 hips (10.3％) had no significant changes and deterioration occurred in 4 hips (3.4％).Conclusion The free vascularized fibular grafting is an effective method for treating osteonecrosis of and preventing the collapse of the femoral head.