國小學童垂直跳與立定跳遠下肢關節動力學參數信度研究
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2003
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大部分的研究，總受限於時間、金錢、設備等因素，選擇較少的實驗施作次數，使得實驗缺乏一定的信度及效度。然而透過實驗所得到的數據資料如果缺乏了信度與效度，所得的結果與結論，即使在統計上達到顯著性，也將不具意義。本研究目的為：(一)分別找出垂直跳與立定跳遠，下肢髖、膝、踝關節運動學參數和動力學參的變異係數。(二)分別找出獲得垂直跳與立定跳遠，下肢髖、膝、踝關節的最大力矩和最大功率的穩定值，所需的最少實驗施作次數。本研究受試者為國小學童30名，隨機分成兩組(垂直跳14 名：年齡12.1±0.8歲，身高153.1±6.9公分，體重50.9±12.4公斤；立定跳遠16名：年齡11.4±0.5歲，身高143.7±11.9公分，體重37.4±12.6公斤)。以一部JVC數位攝影機(60Hz)與Kistler測力板(600Hz)，同步紀錄受試者在垂直跳與立定跳遠項目，矢狀面的運動學、動力學參數。透過動力學逆過程的方法，獲得其下肢關節最大力矩與功率。以序列分析的方法推估國小學童在立定跳遠與垂直跳實驗中，所需的最少實驗施作次數。本研究結論：(一) 垂直跳項目受試者內的動力學參數其變異係數普遍大於運動學參數(離地瞬間的水平速度除外)的變異係數，其中又以髖關節功率的變異係數較大。(二) 立定跳遠項目受試者內的動力學參數其變異係數普遍大於運動學參數的變異係數，其中又以膝關節功率的變異係數較大。(三) 以序列分析推估最佳的實驗施作次數，垂直跳項目為13次，而立定跳遠項目則為14次。本研究結果建議，未來在研究上為了得到動力學參數平均數的穩定值，較多的實驗施作次數是被建議採用的。
In the past, many biomechanical studies were constrained by cost, time, and equipments. One of these factors can lead to poor research directly or indirectly. If researches are not sensitive to the statistical power, it may lead to support null hypothesis and claim the result is demonstrating by the treatments or conditions had the effect. The purpose of this study was to (1) find out every coefficient of variation (CV) of selected kinematic and kinetic parameters on lower limb joint of children during vertical jump (VJ) and standing long jump (SLJ). (2) determine the appropriate number of trials to establish a stable mean and reliability of selected kinetic parameters on lower limb joint of children during VJ and SLJ. Thirty primary school students were selected as subject( In VJ, N=14, age 12.1±0.8 years, height 153.1±6.9 cm ,weight 50.9±12.4 kg; In SLJ, N=16, age 11.4±0.5 years, height 143.7±11.9 cm ,weight 37.4±12.6 kg) to perform 25 trials of maximum VJ or SLJ. One Kistler force plate (600Hz) and one JVC digital camera (60Hz) were used to collect the data. The peak moment and power of lower limb joint were calculated by inverse dynamic method. Sequential estimation technique was used to determine the optimum number of trials. Based on the results of this study (1) In VJ, the most CV of kinetic parameters were bigger than kinematics’. ( not including the horizontal speed of center of gravity of takeoff ) And the kinetic parameter, power of hip joint, was the biggest. (2) In SLJ, the most CV of kinetic parameters were bigger than kinematics’. And the kinetic parameter, power of knee joint, was the biggest. (3) the best number of trials was suggested at least 13-trial for VJ and 14-trial for SLJ by Sequential estimation procedure. Therefore, in order to get a stable mean for kinetic variables, a multiple-trial protocol needed to be adopted.
In the past, many biomechanical studies were constrained by cost, time, and equipments. One of these factors can lead to poor research directly or indirectly. If researches are not sensitive to the statistical power, it may lead to support null hypothesis and claim the result is demonstrating by the treatments or conditions had the effect. The purpose of this study was to (1) find out every coefficient of variation (CV) of selected kinematic and kinetic parameters on lower limb joint of children during vertical jump (VJ) and standing long jump (SLJ). (2) determine the appropriate number of trials to establish a stable mean and reliability of selected kinetic parameters on lower limb joint of children during VJ and SLJ. Thirty primary school students were selected as subject( In VJ, N=14, age 12.1±0.8 years, height 153.1±6.9 cm ,weight 50.9±12.4 kg; In SLJ, N=16, age 11.4±0.5 years, height 143.7±11.9 cm ,weight 37.4±12.6 kg) to perform 25 trials of maximum VJ or SLJ. One Kistler force plate (600Hz) and one JVC digital camera (60Hz) were used to collect the data. The peak moment and power of lower limb joint were calculated by inverse dynamic method. Sequential estimation technique was used to determine the optimum number of trials. Based on the results of this study (1) In VJ, the most CV of kinetic parameters were bigger than kinematics’. ( not including the horizontal speed of center of gravity of takeoff ) And the kinetic parameter, power of hip joint, was the biggest. (2) In SLJ, the most CV of kinetic parameters were bigger than kinematics’. And the kinetic parameter, power of knee joint, was the biggest. (3) the best number of trials was suggested at least 13-trial for VJ and 14-trial for SLJ by Sequential estimation procedure. Therefore, in order to get a stable mean for kinetic variables, a multiple-trial protocol needed to be adopted.
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垂直跳, 立定跳遠, 變異性, 序列分析, vertical jump, standing long jump, variability, sequential estimation procedure