Postawa ciała jest lepsza dzięki temu, że wzmacniam mięśnie.

Literally, postawa ciała is something like the posture of the body.

Polish often uses a noun + noun in the genitive case where English might use:

• body posture
• the posture of the body

Here:

• postawa = posture, stance
• ciała = of the body (genitive singular of ciało)

So postawa ciała is a very natural Polish way to say body posture.

Also, note that postawa by itself can also mean attitude in some contexts, so adding ciała makes it clearly about physical posture.

Because ciała is the genitive singular form of ciało.

The base form is:

• ciało = body

But after another noun like postawa, Polish often uses the second noun in the genitive to show a relationship:

• postawa ciała = posture of the body

This is very common in Polish:

• kolor oczu = color of the eyes
• ból głowy = pain of the head / headache
• koniec dnia = end of the day

So ciała is there because the phrase means the body's posture or body posture.

Because lepsza has to agree with postawa, and postawa is a feminine singular noun.

In Polish, adjectives and similar words must match the noun in:

• gender
• number
• case

So:

• lepszy = masculine singular
• lepsza = feminine singular
• lepsze = neuter singular or non-masculine-personal plural, depending on context

Since postawa is feminine, you say:

• Postawa ciała jest lepsza.

In the present tense, Polish usually does not leave out być (to be) in sentences like this.

So:

• Postawa ciała jest lepsza = Body posture is better

You need jest here.

Polish sometimes omits to be in other structures, especially in the present tense with identity-style sentences in colloquial usage, but with a sentence like this, jest is normal and expected.

Dzięki temu, że means:

• thanks to the fact that
• because
• due to the fact that

It introduces a reason, usually with a positive result.

Breakdown:

• dzięki = thanks to
• temu = this/that, in the dative case
• że = that

So literally, it is something like:

• thanks to this, that...

But in natural English, you usually translate the whole phrase as:

• because
• thanks to the fact that

In this sentence:

• Postawa ciała jest lepsza dzięki temu, że wzmacniam mięśnie.
• My posture is better because I am strengthening my muscles.

Because dzięki requires the dative case.

The pronoun here comes from to (this/that/it, neuter), and its dative form is:

• temu

So:

• dzięki temu = thanks to this / because of this

This is a fixed and very common expression in Polish:

• Dzięki temu wiem więcej. = Thanks to this, I know more.
• Dzięki temu, że ćwiczę, czuję się lepiej. = Because I exercise, I feel better.

Yes, you can.

Possible alternatives:

• bo = because
• ponieważ = because / since
• dlatego że = because

For example:

• Postawa ciała jest lepsza, bo wzmacniam mięśnie.
• Postawa ciała jest lepsza, ponieważ wzmacniam mięśnie.

However, dzięki temu, że often suggests a positive effect more clearly than a neutral bo or ponieważ. Since the posture is improving, dzięki temu, że fits very well.

So all are possible, but the original sounds especially natural because the result is positive.

Because in Polish, a comma is normally used before subordinating conjunctions such as:

• że = that
• bo = because
• ponieważ = because
• jeśli = if
• kiedy = when

So:

• dzięki temu, że wzmacniam mięśnie

The comma is standard Polish punctuation.

English punctuation may differ, but in Polish this comma is expected.

Wzmacniam is the 1st person singular present tense form of wzmacniać, which means:

• to strengthen
• to make stronger

So:

• wzmacniam = I strengthen / I am strengthening

In this sentence, it means the speaker is doing this regularly or as an ongoing activity.

Conjugation of wzmacniać in the present:

• ja wzmacniam = I strengthen
• ty wzmacniasz = you strengthen
• on/ona/ono wzmacnia = he/she/it strengthens
• my wzmacniamy = we strengthen
• wy wzmacniacie = you strengthen
• oni/one wzmacniają = they strengthen

Because Polish verbs have aspect, and here the imperfective verb is the natural choice.

• wzmacniać = imperfective, focuses on the process, repetition, or ongoing activity
• wzmocnić = perfective, focuses on completing the action

So:

• wzmacniam mięśnie = I am strengthening my muscles / I strengthen my muscles
• wzmocnię mięśnie = I will strengthen my muscles

In your sentence, the idea is that the posture is better because of an ongoing habit or process, so wzmacniam is correct.

Mięśnie is the accusative plural form of mięsień (muscle), because it is the direct object of wzmacniam.

Base form:

• mięsień = muscle

Plural:

• mięśnie = muscles

Since wzmacniać takes a direct object, you need the accusative:

• wzmacniam mięśnie = I strengthen muscles / I am strengthening my muscles

For this noun, the accusative plural happens to look the same as the nominative plural, so you see:

• mięśnie

Because in Polish, possessive words like my, your, his, etc. are often omitted when the meaning is obvious from context.

So:

• wzmacniam mięśnie naturally means I’m strengthening my muscles

Polish often prefers the shorter version unless the possession needs emphasis or contrast.

You could say:

• wzmacniam moje mięśnie

But that sounds more emphatic, like:

• I’m strengthening my muscles (not someone else’s)

In normal speech, wzmacniam mięśnie is more natural.

Yes. Postawa can also mean:

• attitude
• stance
• approach

Examples:

• ma dobrą postawę moralną = he/she has a good moral attitude
• jego postawa wobec pracy jest dobra = his attitude toward work is good

That is why postawa ciała is helpful: it clearly means body posture and not attitude.

Yes, Polish word order is fairly flexible, though some versions sound more natural than others.

The original:

• Postawa ciała jest lepsza dzięki temu, że wzmacniam mięśnie.

This is natural and clear.

You could also say:

• Dzięki temu, że wzmacniam mięśnie, postawa ciała jest lepsza.

This puts more emphasis on the reason first:

• Because I strengthen my muscles, my posture is better.

Both are correct. The choice depends on what you want to highlight.

It usually means better, but in context it can strongly imply improved.

So:

• Postawa ciała jest lepsza can mean:
  • My posture is better
  • My posture has improved

If you wanted to say is improving more explicitly, you might use:

• Postawa ciała się poprawia. = Posture is improving.

But the original sentence is perfectly natural if you want to say that the posture is now better as a result of strengthening muscles.

A very natural everyday English version would be:

• My posture is better because I’m strengthening my muscles.

Depending on context, you could also say:

• My posture has improved because I’m strengthening my muscles.
• My posture is better thanks to strengthening my muscles.

Even though the Polish sentence does not explicitly include my, English usually would.