本研究之目的在比較並分析美國及臺灣兩地青少年身體活動程度決定因素之差異性。Pender之健康促進模式(Health Promotion Model, HPM)提供了此兩地的研究架構(Pender, 1996)。此模式中決定健康促進行爲的最主要因素爲：對活動益處及障礙之認知、自我效能、活動相關之因素、人際間之影響、外在情境、對活動計畫的熱衷度、與及時的訴求等。本研究之臺灣樣本爲臺北地區的969位國高中學生（55％男性；45％女性），而在美國之研究樣本爲286位國小高年級及國高中生（48％男性；52％女性）。結果顯示性別在兩地青少年活動程度上具有差異性；男生之活動程度高於女生。結果亦顯示兩地青少年對身體活動障礙的重要性具有跨文化性之差異；美國青少年對身體活動障礙之認知可直接預測其活動程度，臺灣青少年則否。臺灣青少年對自我效能的認知可直接預測其活動程度，而美國青少年卻多受對運動之益處與障礙信念而影響。此外，臺灣與美國青少年之人際關係影響的路徑亦大相逕庭。本研究發現了重要的及文化相關的訊息，可供未來對各青少年身體活動介入研究的參考。

The purpose of this paper is to present a comparative analysis of the determinants of physical activity among adolescents in Taiwan and in the United States. Pender's Health Promotion Model (HPM) served as the theoretical framework for both studies (Pender, 1996). The major determinants of health behavior in the HPM are perceived benefits, perceived barriers, self-efficacy, activity-related affect, interpersonal influences, situational influences, commitment to a plan of action, and immediate competing demands. In Taiwan, 969 middle school students (55% males; 45% females) from Taipei provided data for the study. In the United States, the sample was collected from 286 late elementary and middle school students (48% males; 52% females). Results showed the gender differences in activity levels were apparent in the youths from both countries. In both Taiwanese and American youths, boys were more active than girls, Cross-cultural differences iii the importance of barriers to physical activity emerged. Among Taiwanese adolescents, barriers did not emerge as a significant direct predictor of physical activity as they did among US adolescents. Perceived efficacy directly predicted physical activity among Taiwanese youths while it indirectly predicted physical activity and appeared to be mediated by beliefs regarding exercise benefits and barriers among American youths. In addition, the paths of effect for interpersonal influences were different when Taiwanese and US youths were compared. The findings from this paper have important and culturally-relevant information that can inform future physical activity intervention studies with diverse adolescents.