老年人的身體活動對於其認知功能的效益已逐漸被確認。然而，身體活動如何影響認知功能的作用機轉仍尚未明確。箇中原因可能來自目前對於探討身體活動、認知功能及其中介變項的研究仍缺乏使用適當的研究設計及統計技術，進而釐清三者的複雜關係。因此，本研究旨在探討老年人身體活動影響認知功能以及其中介變項的相關議題，內容包含：(1) 介紹身體活動及認知功能的中介變項之理論模式。(2) 探討分析中介效果應採用的研究設計。(3) 探究應如何選用適當的統計技術以釐清中介效果。本文針對上述議題進行簡要的文獻探討，最後歸結研究發現並提出未來可推動之建議。

It has been increasingly recognized that late-life physical activity has the potential to benefit cognitive function in older adults. However, the mechanism through which physical activity is able to affect cognitive function is still equivocal. It may be due to the lack of empirical study using a proper research design and necessary statistical techniques to elucidate the complex relationships among physical activity, mediators and cognition. Therefore, this study aimed to explore the issues regarding the mediators of physical activity effects on cognition in the elderly. First, the theoretical model of physical activity and its mediators effects on cognition was introduced. Then, the issues regarding appropriate research designs in mediation analysis were discussed. Finally, advice with regard to how to choose a suitable statistical technique to analyze mediation effect was also provided. The study was to address these issues and provided a brief review. Findings and suggestions for future promotion on this topic were proposed.