高台落下跳躍重複施測時測驗間不同間隔休息時間之影響

The Interfering Effects of Lengths of Rest for Repeatedly-Tested Drop Jumps

目的：本研究欲透過40公分高台落下跳躍連續施測結合不同間隔休息時間探究此連續施測之實驗設計是否會對實驗結果形成自身影響。方法：以15名大學體育與運動科學系之非校隊之男性學生為研究對象，進行40公分高台落下跳躍3次，次間休息之操弄共分為三種：30、60、120秒。以兩塊三軸測力板與八台光學攝影機同步擷取資料。以SPSS for Windows 14.0版套裝軟體進行統計分析，並以重複量數單因子變異數分析 (one-way ANOVA)，分別比較以30、60、120秒為高台落下跳躍連續測試次間間隔休息時間為安排時，各運動生物力學參數在三次跳躍的各次結果 (DJ1, DJ2, DJ3)，以及三次結果的平均值 (DJm) 間是否有差異。統計顯著水準訂為α=0.05。結果：以60秒為次間間隔休息時間時，DJ2以及DJm的最大蹬伸力量與反應肌力指數，顯著的較DJ1時大 (p < 0.05)，著地期時間以及膝關節屈曲、蹬伸角位移，顯著的較DJ1時小 (p < 0.05)。結論：本研究在連續三次施測的DJ實驗中發現，以60秒為次間的間隔休息時間時，測驗本身應會對最大蹬伸力量、著地期時間、反應肌力指數，以及膝關節角位移形成影響。若以30秒或120秒為次間的間隔休息時間進行連續施測，則較不易對結果參數形成影響，且以任一次跳躍之結果或以三次結果的平均數進行資料處理，應不會有差別存在。以此，可作為實驗設計或訓練安排時之參考。

 

Purpose: The current study is dedicated to exploring whether the lengths of rests between tests interfere with internal validity of the experiment. Drop jumps from a 40-cm-high platform were discussed in this study. Method: 15 male non-varsity-team undergraduate students from PE department performed drop jumps 3 times repeatedly. Rests between tests were set to be 30 seconds, 60 seconds, and 120 seconds per the purpose of the current study. Kinematic and ground reaction force data were collected using 8 optical cameras and 2 force platforms. A repeated-measure one-way ANOVA was adopted to examine whether the biomechanical parameters were statistically different across drop jumps with different lengths of rests (DJ1, DJ2, DJ3) and between the means of them (DJm). Significance level was set to α=0.05. Results: For tests with 60-sec rest, the peak ground reaction forces and reactive strength indices for DJ2 and DJm were significantly greater than those for DJ1 (p<0.05); the contact times and the angular changes among lower limb joints during squatting and extending phase for DJ2 and DJm were significantly smaller than those for DJ1 (p<0.05). Conclusion: Our findings indicate that for tests with 60-sec rest, the peak ground reaction forces, reactive strength indices, the contact times, and the angular changes among lower limb joints during squatting and extending phase were significantly different. In other words, to avoid unnecessary interference, tests with 30-sec or 120-sec rests were recommended for experiment designs with repeated drop jumps from a 40-cm-high platform. Moreover, DJ1, DJ2, DJ3 and DJm collected from tests with 30-sec or 120-sec rests are more likely to be interference-free for analyses.