Learn Hardcore Japanese: ani ha kenkou no tame ni mainiti hasirimasu. - My older brother runs every day for his health.

The particle は marks “兄” as the topic of the sentence—what we are talking about—whereas が would mark it as the subject presenting new or contrastive information. Since you’re stating a habitual fact about your brother (he runs every day), は is the natural choice.

What does 健康のために mean, and why is the particle の used after 健康?

健康のために literally means “for the sake of health.” Here, の turns 健康 (health) into a modifier of ため, making the phrase “the sake of health.” Without の, you couldn’t link the noun 健康 to ため properly; you’d need something like 健康に but that would mean “in a healthy way,” not “for health.”

What role does ために play in this sentence?

ために expresses purpose or reason. In this case, it tells us why your brother runs: for the benefit of his health. The structure is [noun] + の + ために to indicate “for the sake of [noun].”

Why is there no particle after 毎日?

毎日 is an adverb meaning “every day.” Adverbs in Japanese don’t need a particle when modifying a verb directly. If you used a particle like に, it would change the nuance or force you into a different grammar point (e.g., 毎日に is uncommon here).

Why is the verb 走ります in the present/future tense (–ます form) even though it describes a habitual action?

In Japanese, the non-past tense (dictionary form or polite –ます form) can express both present and habitual actions. So 走ります can mean “he runs” (habitually) or “he will run” depending on context. Here it’s understood as a habitual action: “he runs every day.”

What’s the difference between 走る (dictionary form) and 走ります (–ます form)?

走る is the plain (dictionary) form, used in casual speech or writing. 走ります is the polite present/future form, used in formal settings or when speaking politely. The meaning is essentially the same; only the level of politeness changes.

Could I say お兄さんは健康のために毎日走ります instead of 兄は…?

Yes. お兄さん is more polite or respectful, often used when talking about someone else’s older brother or in formal contexts. 兄 (without honorific) is neutral and typically used in reference to your own older brother in everyday speech.

Why does 健康のために come before 毎日走ります rather than after it?

Japanese generally follows the order: topic + purpose/reason + time/extent + verb. Placing 健康のために (purpose) before 毎日走ります keeps the sentence clear: first establish why he runs, then state how often and what he does. Japanese word order is flexible, but this order is most natural.

Can I drop 兄は and just say 健康のために毎日走ります?

Yes, if context makes it clear who you’re talking about, you can omit the topic. Japanese often drops topics when they’re understood. The sentence 健康のために毎日走ります would simply mean “(He/She/They) run every day for health,” with the subject implied by context.