Skoro ścięgno boli, fizjoterapeuta zmienia plan rehabilitacji.

Here skoro means since, if, or given that. It introduces the reason or condition for what follows.

So:

• Skoro ścięgno boli, ... = Since the tendon hurts, ...
• It suggests: because this is the situation, the physiotherapist changes the rehab plan

A learner should know that skoro can feel a bit like both since and if, depending on context. In this sentence, it is very natural to understand it as since / given that.

Boli is the 3rd person singular form of boleć, which means to hurt / to ache / to be painful.

In this sentence:

• ścięgno boli = the tendon hurts

Polish often uses the present tense where English could use either:

• hurts
• is hurting

So boli does not force a distinction between those two English options.

Also note that Polish expresses this idea differently from English sentences like my tendon hurts or I have tendon pain. Here the tendon itself is the grammatical subject.

Ścięgno is in the nominative singular, because it is the subject of boli.

Structure:

• ścięgno = the tendon
• boli = hurts

So literally: the tendon hurts

The dictionary form is also ścięgno, so here the nominative looks exactly like the basic form.

Because fizjoterapeuta is one of the Polish nouns for professions or people that are masculine even though they end in -a.

This often surprises English speakers. Other similar nouns include:

• mężczyzna = man
• poeta = poet
• dentysta = dentist

So although fizjoterapeuta ends in -a, it behaves grammatically as a masculine noun when referring to a man.

In this sentence, fizjoterapeuta is in the nominative singular and is the subject of zmienia.

Zmienia is the imperfective present-tense form of zmieniać. It means changes / is changing.

Zmieni is usually the perfective future form of zmienić, meaning will change.

So:

• zmienia = changes / is changing
• zmieni = will change

In your sentence, the speaker is describing a general or current reaction:

• If / since the tendon hurts, the physiotherapist changes the rehabilitation plan

That is why zmienia fits well.

Plan is in the accusative singular, because it is the direct object of zmienia.

The physiotherapist changes what?

• plan

For many masculine inanimate nouns in Polish, the accusative singular has the same form as the nominative singular.

So:

• nominative: plan
• accusative: plan

That is why the form does not change.

Because rehabilitacji is in the genitive singular, not the accusative.

In Polish, when one noun modifies another in a relationship like plan of rehabilitation, the second noun is often put in the genitive.

So:

• plan rehabilitacji = rehabilitation plan
• literally: plan of rehabilitation

This is very common in Polish:

• plan dnia = plan of the day / daily schedule
• nauka języka = learning of a language / language learning
• koniec treningu = end of training

So rehabilitacji is correct because it depends on plan.

It is genitive singular of rehabilitacja.

The basic form is:

• rehabilitacja = rehabilitation

Genitive singular:

• rehabilitacji

It appears here because it depends on plan:

• plan rehabilitacji = rehabilitation plan

This is one of the most common noun + noun structures in Polish.

Yes, Polish word order is more flexible than English word order.

The neutral order here is:

• Skoro ścięgno boli, fizjoterapeuta zmienia plan rehabilitacji.

But other orders are possible, for example:

• Fizjoterapeuta zmienia plan rehabilitacji, skoro ścięgno boli.

Both are grammatical. The difference is mostly about emphasis and style.

The original version sounds natural because it first gives the reason/condition, then the result.

A rough English-friendly guide is:

• ścięgno ≈ SHCHENG-no

A few helpful points:

• ś is a soft sh sound
• ci before another consonant helps create that soft sound
• ę is a nasal vowel, though in normal speech its exact pronunciation depends on the sounds around it
• gn in Polish is not the same as English gn in sign; both consonants are pronounced

You do not need perfect pronunciation immediately, but it helps to notice that ść / ści is a very Polish sound combination.

Yes. It is a good example of a very common Polish pattern:

• reason/condition clause + main clause

Breakdown:

• Skoro ścięgno boli = since the tendon hurts
• fizjoterapeuta zmienia plan rehabilitacji = the physiotherapist changes the rehabilitation plan

It also shows several useful grammar points at once:

• skoro introducing a reason/condition
• a subject in the nominative: ścięgno
• a second subject in the nominative: fizjoterapeuta
• a direct object in the accusative: plan
• a dependent noun in the genitive: rehabilitacji

So although the sentence is short, it is structurally very rich and useful for learners.