Effects of the optimal flexor/extensor ratio on G-tolerance

• Published in: Journal of Physical Therapy Science 2016, Vol.28(9), pp.2660-2665
• Main Authors: Park, Jung Sub, Choi, Jean, Kim, Jung Woon, Jeon, Sang Yun, Kang, Sunghwun
• Format: Article
• Language: English
• Subjects: Acceleration; G-tolerance; Isokinetic; Original
• ISSN: 0915-5287; 2187-5626
• DOI: 10.1589/jpts.28.2660

[Purpose] The aim of this study was to examine the flexor/extensor ratio of the knee joints and compare it with the results of Korean Air Force students in G-tolerance test. [Subjects and Methods] The body composition of Korea Air Force students (n=77) was measured by an impedance method. A muscular function test was performed using a Humac Norm (USA) at angular speeds of 60°/sec and 240°/sec and an isokinetic muscular function test was also conducted. [Results] In the failed C and passing groups, muscle mass and fat percentages were significantly higher than those of students in the failed A group. The BMI of the failed C and passing groups were significantly higher than that of the failed A group. The group that passed had a significantly higher value of left knee 60°/sec flexion peak torque than the failed B group. Moreover, the total work of left knee extension of the failed C group and the passing group was significantly higher than that of the failed A group. The C group and the passing group had significantly higher values of the trunk 60°/sec flexor/extensor ratio than the failed A group, and the total work flexor/extensor ratio of the passing group was significantly higher than that of the failed A group. [Conclusions] Based on these results, balance the right and left knee flexor/extensor ratio, and a high flexor/extensor ratio of the trunk are required to endure a high G-tolerance test (+6G/30 sec). Moreover, an improvement in the maximum muscular strength is necessary to endure a situation of rapidly increasing acceleration in the early stage.