Kinematics Analysis of the Glide and Rotational Technique in Shot Put
緒論：過去研究指出，髖關節與軀幹的能量效益在投擲階段與釋放階段過程對投擲距離有較大的影響性，本研究嘗試以鉛球與髂前上棘中心之向量，與矢狀軸形成之夾角，來定義鉛球與髖關節之聯動關係，並比較滑步式與旋轉式動作之各項運動學、鉛球線性動能差異，與瞭解各項運動學參數與投擲距離之關係。方法：以一台Sony DCR-PC330 DV數位攝影機 (Tokyo, Japan) 分別拍攝102年全國運動會五位滑步式與五位旋轉式鉛球投擲，分別各有11次成功投擲，再將影像透過Kwon 3D 3.1版動作分析系統 (Visol, Korea) 進行影像數位化處理並計算各項運動學參數。結果：顯示滑步式與旋轉式在投擲階段時間、出手角度、前導腳著地瞬間之BAX角度與軀幹角度、對側腳離地瞬間之BAX角度達顯著差異 (p < .05)；滑步式之投擲距離與出手速度、離手瞬間之鉛球線性動能為正相關 (p < .05)，且旋轉式之投擲距離與出手速度、對側腳離地瞬間之BAX角度與軀幹角度、出手瞬間之BAX角度、軀幹角度、鉛球線性動能達顯著正相關 (p < .05)。結論：影響滑步式之階段在於投擲階段過程與出手瞬間，而旋轉式則是釋放階段過程與出手瞬間，且滑步式之BAX角度在前導腳著地瞬間必須要越小，旋轉式則在釋放階段要越大。
Purpose: Previous researches indicated that energy efficiency of hip and trunk demonstrated a great influence on throwing distance during the throwing and release phase. So, the current study tried to use the linkage of the mid-point of right and left anterior superior iliac spine and shot put as a vector and measure the angle of the vector relative to the sagittal axis in two dimensions. The purpose of the current study was to compare the difference of the kinematics including the BAX angle between the Glide and Rotational technique and understand the relationship between the kinematic, kinetic energy parameters and throwing distance. Methods: Five Glide technique and 5 Rotational technique shut-putters with 11 successful shot divided were selected in the National Game of Taiwan in 2013. A Sony DCR-PC330 DV camera (Tokyo, Japan) was used to capture their movement and Kwon 3D 3.1 version (Visol, Korea) was used to digitize and calculated each kinematic parameter. Results: It showed that the glide and rotational technique were significantly different (p < .05) in the time duration of throwing, throwing angle, BAX angle and trunk angle at the instant of the leading leg touch down the ground and BAX angle at the instant of the opposite leg off the ground. The throwing distance of the glide technique was positively correlated with the release velocity and linear kinetics at the instant of the release (p < .05). The throwing distance of the rotational technique was positively correlated with the release velocity, BAX angle and trunk angle at the instant of the opposite leg off the ground, and the BAX angle, trunk angle and linear kinetic at the instant of the release (p < .05). Conclusion: The key moment influencing the glide technique was the throwing phase and the instant of the release while that influencing the Rotational technique was the releasing phase and the instant of the release. The BAX angle should be decreased in the Glide technique at the instant of leading leg touch down the ground while that should be increased in the rotational technique in the releasing phase.