本研究主要目的在於針對國內優秀拔河選手，以彈性理論為依據，建立拔河靜態姿勢下肢伸展肌群蹬力之彈性模式，模擬選手在不同重心長度變化量以及不同重心角度下所能產生的蹬力。
假定人體為一彈性體，彈性體長度為身體重心至腳支點的長度，恢復力為下肢肌群作用於測力板之蹬力，以進行彈性模式的模擬。所根據之彈性模式為F=k（△L，θ）△L其中k（△L，θ）為彈性係數函數；F為下肢肌群作用於測力板之蹬力；θ為重心角度；△L為重心長度變化量。
研究對象為國家級拔河選手一人。使用Peak動作分析系統，獲得受試者於不同拔河靜態姿勢之身體重心位置座標，以計算出重心長度變化量及重心角度。並以Kistler測力板獲得受試者下肢肌群蹬力的水平分力為基準，和拉力計配合影片分析資料所求得之拉力的水平分力進行比對，以判定所採之樣本是否符合穩定平衡的條件而作為採樣的依據。
實驗結果顯示實驗值和模擬值間的估計標準誤差值為0.16公斤，不超過平均蹬力值百分之一。因此，以彈性模式針對拔河動作進行模擬不僅可達到單純化的目的，同時亦具有極高的精確度，可有效推估受試者在不同重心角度及不同重心長度變化量下，下肢肌群所產生的蹬力值。

The purpose of this study was to establish a elastic model for investigating the reaction force of lower extremity during different length between COG to foot support point and different angle by COG and floor level in the static posture of tug-of-war. Subject was an elite tug-of-war player who was 21 years old, 170cm height, and 72Kg weight.
Assumed the lower extremity structure was an elastic structure. The length of the structure was regarded as the length between COG and foot support point, and the elastic force was regarded as the reaction force obtained by the force plate. The elastic model established by this study was "F=k(△L,θ)△L", in which k(△L,θ) was a function of elastic coefficient, F was the force plate reaction force, and θwas the angle of COG,△L was the changing length of COG.
The horizontal component of force obtained by the load cell and force plate were tested by the SEE, in order to judge whether the subject in an static balance condition which was able to be an standard of sampling.
The standard error of estimate of the reaction force value obtained between the experiment and the elastic model was 0.16Kg weight which was no more than 1%of mean reaction. Therefore, the elastic model established by this study could provide a good and high accuracy simulation of lower extremity's extension force to the static posture of tug-of -war.