Study on the relationship between leg strength characteristics and G-tolerance of flying cadets based on isokinetic muscle strength test
10.3760/cma.j.cn113854-20240923-00144
- VernacularTitle:基于等速肌力测试的飞行学员腿部力量特征与抗荷耐力关系研究
- Author:
Jie YU
1
;
Jing XUE
;
Xuejian WANG
;
Zhao JIN
;
Baohui LI
;
Yan XU
;
Ke JIANG
;
Xiaoyang WEI
;
Qianyun ZHU
;
Minghao YANG
Author Information
1. 空军军医大学空军特色医学中心加速度生理研究室，北京 100142
- Publication Type:Journal Article
- Keywords:
Acceleration;
Isokinetic muscle strength test;
G-tolerance;
Flying cadets
- From:
Chinese Journal of Aerospace Medicine
2024;35(4):255-261
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the application of isokinetic muscle strength test in the evaluation of flying cadets′ G-tolerance by investigating the leg strength characteristics of different G-tolerance flying cadets.Methods:G-tolerance test: the AMSACC-4E human centrifuge closed-loop mode was used to test the +8 G z tolerance of 89 male fighter flying cadets. The G-tolerance end point of the flying cadets were determined according to physiological signal monitoring, facial expression characteristics and objective comments. According to the test results, the flying cadets were divided into 3 groups: excellent group, good group and failing group.The grouping criteria: excellent group: could complete the +8 G z 10 s test at one time, with no change in the main complaint light and good consciousness. Good group: could complete the +8 G z 10 s test at one time, the main complaint peripheral light dimmed or disappeared, the central light did not change. Failing group: failure to complete the +8 G z 10 s test at one time, occur G-induced loss of consciousness or almost loss of consciousness. Isokinetic muscle strength test: Biodex System 4 Pro isometric test system was used to test the maximum strength, strength endurance and muscle force balance of the leg flexor and extensor muscles of flying cadets. The test indicators include: peak torque, relative peak torque, average power and peak torque flexion ratio. The test site was knee joint of legs. The test angular speeds were 60°/s and 180°/s. The flying cadets were tested once at each angular speed. They were required to do their best to complete 5 times of consecutive flexion and extension at 60°/s, and 20 times of consecutive flexion and extension at 180°/s. Resting 1 min between different speed, and 3 min between different legs test. The leg strength characteristics were compared among 3 groups. Results:There were 52 flying cadets in excellent group, 29 in good group and 8 in failing group. In terms of leg strength: ①maximum strength: under the test of angular speed 60°/s, there was no significant difference in the peak moment and relative peak moment of leg flexor and extensor muscles among 3 groups (all P>0.05). The peak moment and relative peak moment of flexor muscle of left leg in excellent group were lower than those of right leg, with significant differences ( t=2.14, 2.20, P=0.037, 0.032). ②Strength endurance: under the test of angular speed 180°/s, there was a significant difference in the average power of right leg extensor muscle among 3 groups ( F=3.39, P=0.038). The average power of right leg extensor muscle in excellent group was higher than that in good group, with significant difference ( P=0.015). The average power of the left leg flexor muscle in the excellent group was lower than that of the right leg ( t=2.78, P=0.008). ③Muscle force balance: there were no significant differences between the leg peak torque flexion ratio of flying cadets at 60°/s and 180°/s angular speeds (all P>0.05). The peak torque flexion ratio of the left leg of the excellent group was lower than that of the right leg at both angular speeds ( t=3.96, 3.30, P<0.001,=0.002). Conclusions:The strength endurance of the right leg extensor muscles of the flying cadets with excellent G-tolerance is better, suggesting that under the test of angular speed 180°/s, there may be a certain correlation between the average power of leg extensor muscles and the G-tolerance. Maximum strength and muscle balance of the leg are not significant to the G-tolerance of the flying cadets.
