鉛球投擲技術之生物力學分析

Abstract

本研究的目的為（1）分析旋轉式與背向滑步式投擲技術之運動學參數，並探討其與成績表現之相關性。（2）分析旋轉式與背向滑步式投擲技術之地面反作用力參數，並探討其與成績表現之相關性。（3）分析旋轉式與背向滑步式投擲技術之關節力矩、功率參數，應用逆動力學模型來探討鉛球投擲過程中，投擲臂與下肢關節肌肉作用的控制機轉，釐清鉛球投擲技術關節肌肉作用的模式。使用之方法以男性旋轉式與背向滑步式鉛球投擲優秀選手各三位為受試者（均以右手投擲），利用四台高速數位攝影機（125 Hz）同步擷取記錄鉛球選手的三維投擲動作資料，並與兩個測力板（1250 Hz）分別置於投擲圈中間與抵趾板前，同步收集下肢地面反作用力資料，然後透過Kwon 3D動作分析系統與Kwon GRF軟體，進行各參數的分析運算。得到主要結果在旋轉式投擲地面反作用力方面，成績表現與右腳的最大垂直力、最大垂直力發力率、主動期時間、主動期垂直力衝量、垂直總衝量、水平總衝量均有顯著的正相關存在；與左腳最大水平制動力、垂直總衝量、地面反作用力總時間有顯著的正相關存在，與左腳最大水平制動力產生時間-離左腳著地後、水平總衝量有顯著的負相關存在。在旋轉式投擲下肢力矩、功率方面，右腳著地期間，右踝關節為蹠屈力矩起主要作用，並先呈現吸收功率，然後呈現產生功率；右膝關節肌肉作用為屈曲力矩先起主要作用，呈現產生功率，然後伸展力矩起主要作用，並先呈現吸收功率再呈現產生功率；右髖關節為伸展力矩起主要作用，額狀面為先短暫的外展力矩，後為較長的內收力矩起主要作用，並先呈現產生功率，再呈現吸收功率，然後又再呈現產生功率。旋轉式投擲左腳著地期間，左踝關節為蹠屈力矩起主要作用，並先呈現吸收功率，然後呈現產生功率；左膝關節肌肉作用均為伸展力矩起主要作用，並呈現產生功率；左髖關節均為屈曲起主要作用，額狀面均為外展力矩起主要作用，並先呈現吸收功率，然後再呈現產生功率。本研究主要結論在旋轉式投擲方面，旋轉式投擲下肢作用，右腳著地支撐的關鍵期是在主動期作用時間，而且右腳垂直力扮演重要且關鍵的角色，並且要減少右腳的制動作用；左腳的制動作用，雖然與投擲行進方向相反，但是卻有助於投擲成績表現，而且扮演相當關鍵的角色，此外須很快地達到最大水平制動力，並且增加左腳的垂直衝量。旋轉式投擲踝、膝、髖關節肌肉作用，在右腳著地支撐期間，踝關節肌群負責先緩衝，而後推蹬；膝、髖關節肌群負責先旋轉驅動，接下來緩衝，而後推蹬。在左腳著地支撐期間，踝、髖關節肌群負責先緩衝，而後推蹬；膝關節肌群則全程負責推蹬。

Purposes: The purposes of this study were (1) to analyze the kinematics of spin and glide shot put technique and correlate it with performance. (2) to analyze the ground reaction force and impulse and correlate them with performance. (3) to analyze the moment and power of joints of lower limbs. Methods: Three right-handed male spin shot putters and three glide shot putters were subjects. Four high-speed cameras (125 Hz) were synchronized to sample the motion data and were gen-locked with two force plate forms (1250 Hz) which were set in the middle and front of the circle respectively to sample the ground reaction force. Those data were then digitized and calculated with Kwon 3D and Kwon GRF system to get the parameters. Results: In the aspect of spin technique: There were significant positive correlations between the performance and maximal vertical force, maximal loading rate of vertical force, propulsive phase time, vertical impulse in propulsive phase, total vertical impulse and total horizontal impulse on right leg, and maximal horizontal braking force, total vertical force and total ground reaction force time on left leg. There were significant negative correlations between the performance and the time of maximal horizontal braking force and total horizontal impulse. During the right foot landing, the muscle moment about the ankle was net plantar flexion moment and showed power absorption at first and then power generation; the muscle moment about the knee was net flexion moment and showed power generation at first, and then the net extension moment and showed power absorption and then power generation again; the muscle moment about the hip was net extension moment, and on the frontal plane, was net abduction moment at first in a short time and then net adduction moment latter in long time, and showed power generation at first, and then power absorption, and then power generation again. During the left foot landing, the muscle moment about the ankle was net plantar flexion moment and showed power absorption at first and then power generation; the muscle moment about the knee was net extension moment and showed power generation; the muscle moment about the hip was net flexion moment, and on the frontal plane, was net abduction moment and showed power absorption and then power generation. Conclusions: In the aspect of spin technique: The key phase during right foot support was the propulsive phase. The vertical force was crucial and the braking effect of right foot should be reduced in the phase. The braking effect of left foot was in the opposite direction of the throwing, however it was contributive to the performance and crucial. Moreover, the maximal horizontal braking force should be reached quickly and the vertical impulse should be increased. During right foot support, the ankle joint muscles took charge of cushion at fist and then push; the knee and hip joint muscles took charge of spin and the following cushion, and then push. During left foot support, the ankle and hip joint muscles took charge of cushion at fist and then push; the knee joint muscles took charge of push.