Publication:

兒童擺臂與牽張－縮短循環在垂直跳的年齡效應及性別差異

本研究根據「獲取運動速度的最大衝量原理」檢驗垂直跳動作曲線的改變，探討不同年齡及性別的兒童表現有無擺臂及有無SSC行為的垂直跳動作之運動學特徵比較。實驗分別以7、9、11歲之男童與女童各20名為實驗參加者，通過Kistler測力板（model 9287BA，1200Hz）收集實驗參加者執行叉腰蹲踞跳、叉腰垂直跳及擺臂垂直跳的地面反作用力曲線，並以BioWare 3.26版分析軟體進行生物力學參數的計算。統計方法採用3（年齡）× 2（性別）獨立樣本二因子變異數分析，並以Duncan法進行事後比較。研究結果顯示，三種垂直跳躍形式都有年齡及性別上的差異（p< .05），其中叉腰垂直跳表現的年齡差異是由於延長正衝量產生力量的作用力時間（p< .05），致使正衝量隨之增大（p< .05）；而擺臂垂直跳的年齡和性別差異，主要是由於不同年齡及性別兒童擺臂的效益有差異，使正衝量會隨著年齡的增加而變大且男童大於女童（p< .05）。由SSC高度提升率和擺臂提升率發現，7歲兒童已經能有效使用SSC效益，而9歲兒童能有效使用擺臂效益，此外，本研究結果說明各年齡的SSC效益與擺臂效益並無性別差異之存在。

Motor development researchers always regard the proper use of limb swing or proper use of countermovement as the critical indexes for motor skill in child transition to the mature stage. The peak height during a vertical jump is actually enhanced through the effect of vigorous arm swing and the effect of stretch shortening cycle (SSC) that countermoves the lower extremities. The purpose of this study was to investigate the gender difference of the effect of arm swing and SSC in middle/later childhood. Ten boys and ten girls were recruited as the participants and were asked to perform squat jump (SJ), countermovement jump (CMJ) without arm swing, and countermovement jump with arm swing. A Kistler force platform system (type: 9287BA, 1000Hz) was used to acquire and to assess the performance of vertical jump. The results showed takeoff velocity in boys (SJ: 2.23 ± 0.21 m/s; CMJ-arms swing: 2.41 ± 0.22 m/s; CMJ-no arms: 2.31 ± 0.22 m/s) was higher than girls (SJ: 2.02 ± 0.13 m/s; CMJ-arms swing: 2.17 ± 0.14 m/s; CMJ-no arms: 2.12 ± 0.15 m/s) significantly (ps < .05). The peak ground reaction force showed there were no gender difference in conditions of SJ, CMJ-no arms, and CMJ-arms swing (ps > .05). The lengthening force applied time was the main factor to increase jumping height for three kinds of jump (ps < .05). This study calculated the enhanced rates of arm swing effect and SSC effect, and found there were no statistical differences between boys (SSC: 6.7 ± 9.1 %; Arm swing: 10.0 ± 9.4 %) and girls (SSC: 10.1 ± 8.8 %; Arm swing: 5.4 ± 7.9 %) (ps > .05). But the variability of enhanced rates within every gender group for SSC effect and arm swing effect were considerably large.