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Purpose: This study is to get the relevant data among the acceleration of body’s limbs, rotating speed, and soccer speed by using Inertial Sensors and to discuss the differences between the elites and the sub-elites. Methods: Ten athletes of junior high school were chosen to kick the soccer with right foot. They once won the championship of Futsal held by National Physical Committee (Their average age is 15.4±0.7 years old, average height is 170.9±5.2 centimeters, average weight is 61.0±10.5 kilograms, average playing age is 7.6±1.2 years old). Put Inertial Sensors, which consist of Accelerometer and Gyroscope with sampling speed 620 Hz, on their right and left ankles, right and left knees, right waist, and the soccer itself, with the help of high-speed digital cameras and a speed gun. Then analyze the collected data. Results: 1. There is no significant difference on soccer speed whether the athletes wear the sensors or not. 2. On soccer speed , the elites are faster than the sub-elites, and their difference is significant. 3. Stability analysis. The elites are more stable on the following aspects: acceleration of right ankle x-axis, right ankle z-axis, and right waist x-axis; rotating speed of right ankle x-axis and right ankle z-axis. On the other hand, the sub-elites are more stable on the following aspects: acceleration of left ankle x-axis; rotating speed of left ankle z-axis. 4. Time analysis. The elites’ used time as follows is shorter than the sub-elites’: the time for the soccer from zero time to the maximum three-axis acceleration, the time from zero time to soccer leaving right ankle, the time from zero time to the maximum three-axis acceleration for right knee, and the time from left ankle touching ground to soccer leaving right ankle. 5. Concerning the analysis on acceleration and rotating speed, the elites are bigger than the sub-elites for the following aspects: the soccer speed and the soccer rotating speed, the minimum of right ankle z-axis rotating speed, the maximum of right knee x-axis acceleration, the maximum of right knee three-axis acceleration, the maximum of right knee z-axis rotating speed, the maximum of left ankle x-axis rotating speed, the maximum of left knee x-axis acceleration, the maximum of left knee y-axis acceleration, the maximum of left knee three-axis acceleration, the maximum of left knee z-axis rotating speed, the maximum of right waist x-axis acceleration, the minimum of right waist x-axis acceleration, the maximum of right waist three-axis acceleration, and the minimum of right waist z-axis rotating speed. On the other hand, for the following aspects, the elites are smaller than the sub-elites: the minimum of right knee x-axis acceleration, the minimum of right knee y-axis acceleration, the minimum of right knee z-axis acceleration, the maximum of right knee x-axis rotating speed, the maximum of right knee three-axis rotating speed, the maximum of left ankle x-axis acceleration, the minimum of left ankle x-axis acceleration, the maximum of left ankle y-axis acceleration, the minimum of left ankle y-axis acceleration, the minimum of left ankle z-axis acceleration, the maximum of left ankle y-axis rotating speed, the maximum of left ankle z-axis rotating speed, the minimum of left knee x-axis acceleration, the minimum of left knee y-axis acceleration, the minimum of left knee z-axis acceleration, the minimum of left knee z-axis rotating speed, the maximum of right waist x-axis rotating speed, and the maximum of right waist three-axis rotating speed. 6. Correlativity analysis on acceleration, rotating speed and average soccer speed. Athletes marked a, b, c, d, e, f, g, h, i, and j have significant correlativity on 3, 6, 11, 9, 16, 9, 4, 17, 1, and 7 items respectively. 7. Correlativity analysis on right knee and right ankle. Athletes marked a, b, c, d, e, f, h, and i have significant correlativity on, 2, 1, 2, 1, 3, 2, 1 items respectively. Conclusions 1.Whether the athletes wear the sensors or not may not influence their performance. 2. Inertial Sensors can make the analysis and comparison on soccer speed of both groups. 3.Inertial Sensors can make the analysis on limb’s stability of both groups. 4.Inertial Sensors can make the analysis on the kicking time of both groups. 5. Inertial Sensors can make the analysis on acceleration and rotating speed of soccer and limbs. 6. Inertial Sensors can make the analysis on correlativity among acceleration and average soccer speed, and among rotating speed and average soccer speed. 7. Inertial Sensor can make the analysis on correlativity among the limbs. Suggestions: To undertake the training programs for the sub-elites, coaches may get started from their differences, and make the elites as the standards. With the help of Inertial Sensors and by the professional experiences and judgments, coaches can find out the weakness of limbs for the athletes, design the training programs for different limbs to improve the weakness, and reinforce training on muscular strength and endurance of lower limbs, in order to increases instantaneous force and soccer speed as well. By this, not only the sub-elites but also the elites can improve soccer speed and its rotating speed. That is to get the most effect of training with the least time and to increase the possibility of scoring accordingly.
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