不同蹲踞式起跑動作加速期之生物力學分析

Abstract

目的：本研究主要目的在探討不同蹲踞式起跑動作對起跑出發階段以及起跑後加速度階段之差異。方法：受試者為8名大學田徑隊短距離男子選手(身高：173.16±4.77公分；體重：65.55±4.52公斤；年齡：20.06±1.09歲)，實驗中，起跑出發階段與起跑後加速度階段分別使用1部iX Cameras, i-SPEED 210高速攝影機(250Hz)和3部CASIO, EX-ZR100高速攝影機(240Hz)，分別收集起跑出發階段至起跑後加速度階段前三步以及起跑後加速度15、25、35公尺動作影像資料，再以Kwon 3D軟體計算相關運動學參數。而起跑架前、後踏板反作用力則是以40片壓力感測片(前、後各安裝20片)，擷取頻率1000Hz，收集踏板動力學資料，另於0-60公尺架設6部樹莓派相機(30Hz)，擷取每10公尺區間之分段時間資料。實驗數據以無母數統計弗里曼二因子等級變異數分析，比較起跑模式間的差異，若有達到顯著差異，則進行事後比較，事後比較採等級平均數法進行，顯著水準為 α=.05。結果與討論：結果顯示不同起跑模式在預備階段，臀部及重心高度會直接影響前、後腳髖、膝、踝關節角度，進而影響鳴槍後相關動力學參數與起跑後前三步步幅、著地重心速度以及15、25、35公尺平均步幅。在起跑出發階段，長式的身體重心位移距離長，重心速度快，後腳推蹬踏板產生的初始發力率、最大發力率較大；但短式起跑的時間有最短的趨勢。在起跑後加速度階段，長式起跑第一步步幅大、前二步著地重心速度快；至於起跑出發階段銜接起跑後加速度階段則以中式起跑法在0-60公尺時間表現上，有較佳的表現。結論與建議：結果發現短式起跑有較佳的起動表現；而中式起跑可以增加起跑出發階段銜接起跑後的加速穩定性。建議我國的選手未來可以在起跑出發階段方面，改變起跑架前踏板與起跑線的距離為 1.5個足長，以利整體起跑出發表現。

Purpose: The purposes of this study were to compare the differences among the different crouching start block patterns in the starting phase and the acceleration phase after the trigger. Methods: Eight collegiate track and field short-distance runners served as the participants (height: 173.16±4.77 cm; weight: 65.55±4.52 kg; age: 20.06±1.09 years old). One iX Cameras, i-SPEED 210 high-speed camera (250 Hz) and three CASIO, EX-ZR100 high-speed cameras (240 Hz) were used in the starting phase and the post-start acceleration phase, respectively. The kinematic variables of the start and the acceleration phase and the 15, 25, 35m motion image data were calculated by Kwon 3D software. Twenty pieces of reaction tranducer sensors (1000Hz) were installed on the front and rear pedals each of the start block to measured the reaction force during start phase. Six Raspberry Pi cameras (30 Hz) collected every 10m interval duration time from 0-60m. The experimental data were compared by the Friedman two-way analysis of variance by ranks nonparametric statistical test among the different patterns at a .05 significant level. Results and discussion: The results showed that the different starting modes were in the set stage, and the hip and COM directly affect the angles of the hips, knees and ankles of the front and rear feet, and the kinetic parameters after the trigger. That might influence the performance of the first three steps after the start, the speed of the center of gravity and the average stride length of 15, 25, 35 meters. Since we found that the kinematics and dynamics parameters were better in the starting phase in the elongated start mode, but the overall starting time was better in the shorten mode. Conclusions and Suggestions: From the results, we found there were no significant differences among the four starting mode. The shorten mode seemed performed the fastest trend in the start phase of the starting. The medium start mode could maintain the connection between the starting phase and the acceleration phase after the start in increasing velocity of the start and the stability during the start and the acceletaion phase of the sprint. We recommend that changing the distance between the front pedal and the start line to one and half foot length to increase the performance of the sprint start.