شناسايي استراتژي كنترل تعادل، در اجراي بالانس روي پارالل

Applied strategies for maintaining handstand posture on the parallel bars

The purpose of this study was to determine the applied strategies for maintaining handstand posture on the parallel bars. Methods: Eight experienced gymnasts (mean age 16.62 ｱ 1.59 years, height 160.75 ｱ 4.94 cm and weight 53.24ｱ 7.14 kg) participated in the study. Eighteen reflective markers were placed on anatomical landmarks to define different body segments. The subjects were instructed to maintain a handstand posture on the simulated parallel bars (three trials). Data collected using three high­speed cameras (Motion Analysis System) at 120 Hz for 5 seconds. Anthropometric parameters including total body mass, as well as length and mass of each segment were recorded. The joint angle ranges, angular velocity and acceleration of the joints were calculated with Eva software. Inverse dynamic equations in MATLAB environment were employed to calculate wrist, elbow, shoulder and hip joint torques using a 5-segment model. The data was filtered with cut-off frequency of 2 Hz. MANOVA and paired t-test were used for statistical analyses (p<0.05). Results: Whole-body COM and center of mass of segments of the body deviations both were greater in anterior-posterior direction than medio-lateral direction. All joint torques contributed to control of posture, but wrist joint played a dominant role in comparison with the others. Conclusion: Results demonstrated that the strategy for maintaining an inverted balance on the parallel bars a multiple joints torques including wrist, elbow, shoulder and hip are exhibited great magnitude during handstand position respectively.