研究的主要目的在瞭解台北市國中學生之身體活動量、社會影響因素與健康體能之狀況並比較體適能水準、社會支持、自我效能及體適能知識在不同等級身體活動量之差異。本研究以台北市八所國民中學學生為母群，採分層隨機抽樣法抽出研究樣本676名，參加體能檢測與問卷調查，體能測試項目有1.身體質量指數，2.一分鐘仰臥起坐，3坐姿體前彎，4.心肺耐力。本研究將身體活動量以百分位法分成低、中、高三組做比較，所獲得的資料與活動量值以單因子變異數與逐步迴歸分析處理，結果發現：一、本研究對象的身體活動量因性別、年級等個人背景因素而有顯著的差異。二、本研究對象在假日所從事的中重度身體活動頻率較平時多，且其中以類似打棒(壘)球、排球、桌球、保齡球、騎腳踏車等的休閒活動居多。 三、本研究對象的身體活動量與運動社會支持、運動自我效能、健康體適能因素呈顯著正相關四、身體活動量可由社會支持、自我效能、有無規律運動來預測，並可解釋18.3 %的變異量* F若加入性別、年級一併分析，則可解釋23.8 %的變異量，其中以自我效能最具預測力。五、在高活動量組中，研究對象之運動自我效能、運動社會支持、體適能之肌力與 肌耐力、心肺耐力顯著高於中活動量組；中活動量組之運動自我效能、運動社會支持、體適能之心肺耐力顯著高於低活動量組。根據本研究結果，適度增加學生之社會支持及運動自我效能有助於學生 身體活動量的提昇，且不論是休閒或星期假日時的各類身體活動參與亦 能有效增加活動量與健康體適能。因此，建議教育單位可由建立健康體能觀念、加強學生社會學習與規律性的身體活動以及多鼓勵女學生於學校內及休閒時各種身體活動的參與，以達到降低慢性疾病與增加健康體能之重要目標。

The purpose of this study were to determine the physical activity level and its affecting factors of junior students in Taipei City. The physical fitness , social support , self-efficacy and physical fitness knowledge classified by 3 varied degree of physical activity level of each subjects , were classified to compare the difference.In addition , the related variables were used to predict the physical activity levels. Totally 676 junior students from 8 junior schools in Taipei City were stratified and chosen randomly as subjects.Each subject was asked to fill out the designed questionnaires of the related variables and received a battery of physical fitness test . The physical fitness test items included: 1)body mass index, 2) one-minute sit - up ,3) sit and reach , 4)1600m (male) or 800m (female)run-walk test. The data were analyzed by one-way ANOVA and Step-wise linearregression , the results were followed: 1.The sex and age of the subjects have a significant effect on physical activity.2.The junior students involved more in moderate-vigorous physical activities on weekend leisure time than that of weekday. The more popular activities were playing baseball, soft baseball, volley ball, table tennis, ten pins bowling, and riding bicycle.3.The moderate-vigorous physical activity of junior students had significant relationship with social support , self-efficacy and physical fitness.4.The 18.3% variance of physical activity could be explained by self-efficacy, social support and regular exercise habits . The 23.8% variance could be predicted if sex and age were added for analysis. 5.The self-efficacy, social support , muscular endurance, cardiovascular endurance of high physical activity subjects were significantly better than that of middle physical activity ones. The self-efficacy, social support , cardiovascular endurance of middle physical activity subjects were significantly better than that of low physical activity ones.