taikensanka wo kikkake ni, undougutu wo katta.

体験参加 is a compound noun:

• 体験 = experience, trial, trying something out
• 参加 = participation, joining

Together, 体験参加 means something like trial participation or joining something on a trial basis.

In natural English, this often refers to things like:

• attending a club activity once to try it out
• joining a class for a trial session
• taking part in an event as a beginner or guest

So it suggests the speaker tried participating in something, and that led to the later action.

In 体験参加をきっかけに, the を is part of the grammar pattern:

• N を きっかけに
• using N as a trigger / taking N as an opportunity

So を is not marking the direct object of a verb like 買う here. Instead, it marks the thing that became the starting point or trigger for what happened next.

So:

• 体験参加をきっかけに = prompted by the trial participation / taking the trial participation as an opportunity

きっかけ means trigger, prompt, cue, or opportunity that causes something to happen.

The pattern N を きっかけに means:

• because of N as a trigger
• taking N as an opportunity
• prompted by N

It often describes a change or new action that happened after some event.

In this sentence:

• 体験参加をきっかけに、運動靴を買った。
• The trial participation became the trigger, and as a result, the speaker bought athletic shoes.

So the nuance is not just simple cause-and-effect, but more like:

• That experience got me started
• That event prompted me to do it

Good question. These forms can all relate to reasons, but the nuance is different.

• から / ので = straightforward reason or cause

  • 雨だから行かない。 = I won’t go because it’s raining.

• ために can mean for the sake of or sometimes a more formal because of, depending on context.

• をきっかけに specifically means using something as a trigger or turning point.

So 体験参加をきっかけに、運動靴を買った。 is not just:

• I bought athletic shoes because I did trial participation

It is more like:

• After trying it out, that experience prompted me to buy athletic shoes
• The trial participation served as the catalyst for buying the shoes

That trigger / turning-point nuance is the key.

Here, に is part of the fixed expression をきっかけに.

It helps express the idea of:

• on the occasion of
• as a turning point
• as an opportunity

You should learn をきっかけに as a set phrase.

Common patterns include:

• Nをきっかけに
• Nをきっかけとして
• Nがきっかけで

They are similar, though not always identical in nuance or style.

Yes. A very common alternative is:

• 体験参加がきっかけで、運動靴を買った。

This also means that the trial participation was the trigger for buying the shoes.

Very roughly:

• N をきっかけに = taking N as an opportunity / using N as a trigger
• N がきっかけで = N was the trigger, and because of that...

Both are natural. The version with をきっかけに can sound a little more like using that event as a starting point.

Yes. Japanese often omits the subject when it is clear from context.

So this sentence could naturally imply:

• I bought athletic shoes...
• we bought athletic shoes...
• he/she bought athletic shoes...

But in many everyday situations, a learner will first interpret it as I bought athletic shoes, especially if it appears in a personal statement or conversation.

The omitted subject does not make the sentence incomplete in Japanese.

運動靴 specifically means athletic shoes, sports shoes, or sneakers.

• 靴 = shoes in general
• 運動靴 = shoes for exercise or sports

Because the trigger was 体験参加, the context probably involves some physical activity, sports club, class, or event. So 運動靴 is more specific and more natural than just 靴.

買った is the plain past form of 買う.

It shows that the action of buying the shoes is completed.

The plain form is used because this sentence is in a casual or neutral written style, not in polite です／ます style.

Compare:

• plain: 運動靴を買った。
• polite: 運動靴を買いました。

Both are grammatically fine; the difference is just style and politeness.

Japanese often puts background information or context first.

So:

• 体験参加をきっかけに、運動靴を買った。

means roughly:

• As a result of that trial participation / Taking that trial participation as the trigger, I bought athletic shoes.

This order is very natural in Japanese because it introduces the setup first and the main action second.

The comma after に helps separate the introductory context from the main action:

• 体験参加をきっかけに、 = trigger/background
• 運動靴を買った。 = main statement

It makes the sentence easier to read, but punctuation in Japanese is often somewhat flexible. The sentence could still be understood without the comma.

Yes. In Japanese, many action-related words can function as verbal nouns or suru-nouns.

参加 is a classic example:

• 参加 = participation
• 参加する = to participate

Similarly, 体験参加 can be used as a noun:

• 体験参加をきっかけに

You could think of it as the trial participation or my trying it out.

This is very common in Japanese: an action can be packaged into a noun phrase and then used with patterns like をきっかけに.

It strongly suggests after.

The sequence is:

1. there was 体験参加
2. that became the きっかけ
3. then the speaker bought athletic shoes

So the trial participation came first, and it motivated the later purchase.

No. It can be used for both big and small changes.

Examples:

• small change: trying a class once and then buying shoes
• bigger change: moving to Japan and then starting to study Japanese seriously

What matters is that something acts as a trigger or starting point, not how dramatic it is.

In this sentence, the change is fairly small and practical: the experience prompted the speaker to buy athletic shoes.

Yes, it is natural.

It sounds like the speaker is explaining what prompted the purchase:

• they joined something on a trial basis
• that experience made them decide to buy athletic shoes

A very natural real-world context would be:

• trying out a sports class
• attending a gym session
• joining a club activity once

After that, they realized they needed proper shoes.

So the sentence is concise but quite natural.