| Summary: | 碩士 === 國立臺灣師範大學 === 體育學系 === 106 === Introduction: In recent years, Asian athletes have become more competitive in the field of race walking, most notably in their performance at the Olympics. The improvement in performance can be attributed to more advanced training techniques. Previous studies indicate that lower limb movement is the most important factor in overall performance of race walkers. The purpose of this study is to compare the lower limb movements of Taiwanese elite junior race walkers at two different speeds (high speed 90% and low speed 60%) in order to observe any differences in technique. Methods: Eight elite junior race walkers in Taiwan ( 4 males and 4 females, height: 1.64 ±0.08 m, weight: 55.5±6.5 kg, age: 14.6±0.7 years, training age: 3±0.5 years, ) participated in this study. Eight Vicon Motion System cameras ( 200Hz ) and two Kistler force plates ( 1000Hz ) were used in conjunction to capture lower limb movement. Five successful gait cycles for two speeds were collected, of which the most stable gait cycle out of the captured movements was used for comparison of the kinematic and dynamic parameters. A paired sample t test was performed for statistical analysis ( α = .05 ). Results: At the point of the heel strike, the ankle’s angle of dorsiflexion is significantly larger when walking at the higher speed, while the knee does not extend as fully for both speeds. In toe off phase, the ankle’s angle of plantar flexion is significantly smaller at higher speed. Both left and right feet’s GRF in the stance phase is considerably larger at higher speed. At high speed, the stance phase to swing phase time ratio is 48.9 : 51.1, while at low speed the time ratio is 51.9 : 48.1. As the speed increases, time spent in stance phase decreases, while time spent in swing phase increases. Conclusion:（1）When training at low speed for long distances, the athlete’s lower limb joints have more control over the angle of movement in stance phase and can fully extend their movements, therefore effectively increasing utilization of joint mobility.（2）At higher speed, the GRF during stance phase is greater and efficient use of ankle strength can help to drive the body forward.（3）Also at higher speed, time spent in stance phase is reduced, while time spent in swing phase is accordingly increased.
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