膝關節角度變化對於垂直蹲跳表現之影響

The influence of knee joint angle change on verticallysquat jumps performance

前言：力量與動作時間是影響動作表現的兩大要素，關節角度的不同會形成不同的肌長度與肌肉施力方向，進而改變力量之產生。另外，動作型態的改變會影響動作時間之長度，故本研究旨在探討膝關節不同預蹲角度之蹲踞跳對跳躍動作之力量、時間與跳躍表現的影響。方法：以20名東華大學體育學系男性學生為對象，分別進行五種膝關節預蹲角度（50、70、90、110、130度）之蹲踞跳。以高速攝影機與三軸測力板同步擷取資料。以動作分析軟體執行影像與地面反作用力之資料處理，並將所得之生物力學相關參數以重複量數單因子變異數分析與進行統計考驗，比較五種不同預蹲角度間在下肢力量、動作時間與動作表現等參數上是否有差異，並以皮爾森積差相關探討角度與各參數間之相關，設定α=.05為顯著水準。結果隨著膝關節預蹲角度的增大，跳躍高度、動作時間與衝量值呈現下降的趨勢，而最大地面反作用力、發力率以及爆發力則隨著膝關節預蹲角度的增大而增加。角度與跳躍高度、動作時間及衝量值呈顯著負相關，而角度與最大地面反作用力、發力率以及爆發力則呈顯著正相關。結論與建議：SJ動作中，採不同的膝關節預蹲角度會影響跳躍表現，較小的膝關節預蹲角度可有較長的動作時間，有利於衝量的累積，使得SJ跳躍表現較佳，而較大的膝關節預蹲角度可在SJ動作中產生較佳的肌力表現。

Background: The two major factors of influencing movement performance are strength andmovement time. Different joint angles would lead to different muscle lengths and force directions，and then change the production of strength. In addition， the change of the movement pattern willinfluence the movement time. So， the purpose of this study was to examine the effect of squatjumps (SJ) at different knee starting angles on the strength， movement time and performance.Methods: Twenty male students from the Department of Physical Education of Dong HwaUniversity were recruited and they were required to perform SJ tasks at five knee starting angles(angles: 50°， 70°， 90°， 110°， and 130°). Data was obtained with synchronization using a MegaSpeedhigh-speed cinecamera and three axle force plates of AMTI. The image and ground reacting forcedata were processed with Kown software. The repeated measures of One-way ANOVA analyzingstatistics test for relationship parameter of biomechanics was obtained. We made comparisonsamong five knee starting angles on parameters of lower-limb strength， movement time， andmovement performance. The Pearson’s product-moment correlation coefficient was used to probethe correlation between angles and parameters. The level of significance was α=.05. Results: Alongwith the increase of knee starting angles， the jump height， movement time and impulse had thetendency to decrease whereas the peak ground reaction force (PRFD)， power， and explosive forcehad the tendency to increase. The knee starting angle showed a significant negative correlationbetween jump height， movement time and impulse; but it showed a significant positive correlationbetween peak ground reacting force (PRFD)， power， and explosive force. Discussion andConclusions: The results of this study indicated that different knee starting angles could influencethe jumping performance. The smaller angle could lead to longer movement time which was infavor of impulse accumulation and could help to perform the squat jump better; whereas， the biggeran