本研究的目的在探討後天環境對單卵雙胞胎健康體適能測試表現的影響。九對桃園縣官立國小的健康單卵雙胞胎(平均年齡10.22歲)，單卵雙胞胎之篩選是以(1)年齡(2)性別(3)型態(4)血型來做鑑刑，分別就健康體適能的五大要素:肌力(左右手握力、屈膝仰臥起坐30秒)、肌耐力(屈膝仰臥起坐60秒)、柔軟度(坐姿體前彎)、身體組成(身體質量指數)和心肺耐力(三分鐘登階測驗)進行測試。資料收集後以SPSS/Windows+套裝軟體加以統計分析，以相依樣本配對組法t檢定和Pearson積差相關法來分析結果，統計顯著水準定為α=0.05。於本研究之範固與限制內，依研究結果顯示，得到下 列之結論:(-→年齡不大的單卵雙胞胎，其因具相同的遺傳因于，故其生理表徵具相當程度的相似性，然於體過能測試表現則差異性頗大，並主現出全身性與局部性運動表現的差異。位)體適能表現受後天生活環境影響的程度，由大到小、 分別為:肌力(左、右手握力»肌耐力(屈膝仰臥起坐»是軟度(生姿體前彎»心肺功能(登階測驗)。

The purpose of this study was to examined the effects of heredity and environment on physical fitness test performance on monozygotic twins. Monozygotic twins were classfied on the .basis of (1)age (2) sex (3) morphology (4) blood type. Nine pairs of Taoyuan county elementary school monozygotic twins (mean age: 10.22 years) were tested for muscle strength (leftand right hand; sit-up 30s)， muscle endurance (sit-up 60s)， flexibility (sit-reach)， body composition (body mass index)， and cardiovascular fitness (3-min step test). Data were analyzed used the SPSS/ Windows + statistical software package with paired-samples t-test and Pearson coηelation coefficients. Statistical significant was set atα=0.05. Theresult of this study was show that: (1)a significant genetic effect is present in monozygotic twins for physique but that a much lower heritability exists for physical fitness test performance. (2)the magnitude of �he environment effects on physical fitness test was as follow: muscle strength (leftand right hand) > muscle endurance (sit-up) > flexibility (sit司reach) > cardiovascular fitness (3-min step test).