Okay, the user wants me to translate "decreased mobility" into Traditional Chinese. Let me check the rules again. The first rule says to translate all content into Traditional Chinese. The second rule states that if the content is already in Traditional Chinese, output it unchanged. The third rule is to provide only the translation result without explanations.
So, the input here is "decreased mobility," which is in English. I need to translate that. The term "decreased mobility" can be translated as "活動能力下降" in Traditional Chinese. Let me confirm that. "Decreased" is "下降" or "減少," but "下降" is more commonly used for a decline in ability. "Mobility" here refers to the ability to move, so "活動能力" is appropriate.
I should make sure there's no existing Traditional Chinese text in the input, which there isn't. So the correct translation should be "活動能力下降." No explanations, just the translation. Alright, that should do it.