Я купил кроссовки для прогулок, потому что в старой обуви мне неудобно ходить.

Купил is the perfective past form of купить, so it presents the action as completed: I bought.

That fits this sentence because the speaker is talking about a finished result: they now have the sneakers.

If you used покупал, it would sound more like:

• the process of buying,
• a repeated action,
• or background information in some contexts.

So here:

• Я купил кроссовки = I bought sneakers / I bought a pair of sneakers

Also, купил tells you the speaker is grammatically masculine singular. A woman would say купила.

In Russian, items that normally come in pairs are very often named in the plural:

• кроссовки = sneakers
• ботинки = boots/shoes
• брюки = trousers
• ножницы = scissors

So Я купил кроссовки is the normal way to say I bought sneakers / a pair of sneakers.

If you want to be extra explicit, you can say:

• пару кроссовок = a pair of sneakers

But in everyday Russian, just кроссовки is completely natural.

Because для requires the genitive case.

The base word is:

• прогулка = walk, stroll

After для, it changes:

• для прогулки = for a walk
• для прогулок = for walks / for walking / for strolls

Here для прогулок is very natural because it means something like:

• for walks in general
• for walking
• for going on strolls

So:

• кроссовки для прогулок = sneakers for walks / walking shoes

Because потому что is the full conjunction meaning because.

Examples:

• Я ушёл, потому что устал. = I left because I was tired.
• Я купил кроссовки, потому что... = I bought sneakers because...

By itself, потому usually means something closer to:

• for that reason
• that’s why

For example:

• Я устал, потому и ушёл. = I was tired, and that’s why I left.

So in your sentence, потому что is the normal choice.

Because потому что introduces a subordinate clause.

Russian punctuation usually places a comma before conjunctions like:

• потому что = because
• когда = when
• если = if
• что = that

So:

• Я купил кроссовки для прогулок, потому что...

This is standard Russian punctuation.

Because обувь is usually a singular collective noun in Russian.

It means footwear / shoes as a category, not one single shoe. So Russian often uses singular where English might think in plural terms.

Compare:

• старая обувь = old footwear / old shoes
• новая обувь = new footwear / new shoes

So:

• в старой обуви = in my old shoes / in old footwear

The plural обуви exists, but it usually means different kinds/types of footwear, not an ordinary pair of shoes someone wears every day.

So в старой обуви is the natural phrasing here.

It is the prepositional case after в.

Here в means something like in / while wearing:

• в обуви = in shoes / wearing shoes
• в старой обуви = in old shoes / wearing old shoes

Forms:

• старая обувь = nominative
• в старой обуви = prepositional

Both words change:

• старая → старой
• обувь → обуви

This is a very common pattern with в + prepositional.

Russian often uses в + clothing/footwear to mean dressed in / wearing something.

Examples:

• Она в пальто. = She is wearing a coat.
• Он в шапке. = He is wearing a hat.
• Мне неудобно ходить в этих ботинках. = It’s uncomfortable for me to walk in these boots.

So в старой обуви literally looks like in old footwear, but idiomatically it means:

• wearing old shoes
• in my old footwear

English and Russian just package this idea differently.

This is a very common impersonal construction in Russian:

• мне неудобно = it is uncomfortable for me
• literally: to me, it is uncomfortable

Russian often expresses feelings or states this way:

• мне холодно = I am cold
• мне скучно = I am bored
• мне трудно = it is hard for me
• мне неудобно = it is uncomfortable for me / I feel uncomfortable

So:

• мне неудобно ходить = it is uncomfortable for me to walk

The person experiencing the feeling goes into the dative case:

• я → мне

Because неудобно here is not an adjective describing a noun. It is a predicative adverb/state word meaning:

• uncomfortable
• inconvenient
• awkward

In this structure, Russian uses forms like:

• удобно
• неудобно
• трудно
• легко
• холодно

Examples:

• Мне удобно. = I’m comfortable / It’s convenient for me.
• Мне неудобно сидеть. = It’s uncomfortable for me to sit.
• Мне трудно понять. = It’s hard for me to understand.

If you used неудобный, that would describe a noun:

• неудобная обувь = uncomfortable shoes
• неудобный стул = an uncomfortable chair

But here the sentence is about the experience of walking, so неудобно is right.

Because ходить is the better choice for a general, repeated, or non-one-time action.

Here the idea is:

• walking in those old shoes is uncomfortable in general
• not just one specific trip at this exact moment

Compare:

• идти = to be going, to walk in one direction, often a specific occasion
• ходить = to walk, go on foot generally, habitually, repeatedly, or back and forth

So:

• мне неудобно ходить = it’s uncomfortable for me to walk
• general statement

If you said мне неудобно идти, it would sound more like:

• it’s uncomfortable for me to walk/go right now in a particular situation

Not quite. Прогулка usually means a walk/stroll for pleasure, not just walking as basic movement from one place to another.

So:

• кроссовки для прогулок suggests sneakers for walks, strolling, casual walking
• not specifically running shoes or formal shoes

It has a relaxed everyday feel:

• going for a walk
• taking a stroll
• walking around outside

Yes, that would also be possible, but it changes the wording slightly.

• в старой обуви = in old footwear / in my old shoes
• в старых кроссовках = in my old sneakers

The original sentence is a bit broader and more neutral:

• the old footwear is uncomfortable
• so I bought sneakers for walks

If you say в старых кроссовках, it becomes more specific: the old sneakers are the problem.

So the original version sounds natural if the speaker is talking generally about their previous footwear.

The word order is natural, but Russian word order is more flexible than English.

Original:

• Я купил кроссовки для прогулок, потому что в старой обуви мне неудобно ходить.

This is neutral and clear:

1. what I did,
2. then why.

You could rearrange parts for emphasis, for example:

• Мне неудобно ходить в старой обуви, поэтому я купил кроссовки для прогулок. = It’s uncomfortable for me to walk in my old shoes, so I bought sneakers for walks.

Or:

• Я купил для прогулок кроссовки... This is possible, but less neutral in everyday speech.

So the original order is probably the most standard and learner-friendly version.

Yes. Неудобно is a flexible word.

Depending on context, it can mean:

• physically uncomfortable
• inconvenient
• socially awkward/embarrassing

Examples:

• Мне неудобно сидеть на этом стуле. = It’s uncomfortable for me to sit on this chair.
• Мне неудобно ехать так рано. = It’s inconvenient for me to travel so early.
• Мне неудобно спрашивать. = I feel awkward asking.

In your sentence, because it is about shoes and walking, the meaning is clearly physically uncomfortable.