부산대학교 도서관

Purpose: To explore the factors that may affect the successful rate of performing lotus kick with 360˚ twist followed by one knee raised landing in taijiquan athletes. Methods: Eight college level of taijiquan athletes participated in this study. A high speed infrared camera system was synchronized with a force plate for data collection and motion analysis. Each athlete required to perform 10 times of the designated movement. Whether each of the performance was successful or not was decided by three national-level referees. Biomechanical variables analyzed in this study included jump height, jump power, time difference between the moment of slamming the kicking leg and the moment of center of mass (COM) reaching the highest point, vertical displacement of the COM, direction and speed of the kicking leg, horizontal displacement of the COM after landing, and the time difference between the moments of the hip and knee joint movement start. Mann-Whitney U tests were used to compare the differences in demographic data and the variability of each biomechanical variable between 4 athletes with higher successful rate and 4 athletes with lower successful rate. Due to the sample size in this study was small, each biomechanical variable was categorized into several levels. Chi-square tests were conducted to examine whether there were significant relationships between successful (33 times)/unsuccessful (47 times) jumps and the count distribution of different levels in each biomechanical variable. Results: The group with higher successful rate had heavier body weight and longer practicing experience. They also had less variability in the variables of jump height, time difference between the moment of slamming the kicking leg and the moment of COM reaching the highest point, and direction of the kicking leg. Chi-square tests revealed that successful jumps had greater jump height than unsuccessful jumps. Conclusion: In addition to the body weight and practicing experience that may affect the successful rate of performing the lotus kick in this study, taijiquan athletes can try to increase their jump height and to improve the consistency of their own jump movements to increase their successful rate.