Learn Hardcore German: Meine Schwester geht dreimal pro Woche ins Fitnessstudio. - My sister goes to the gym three times a week.

Meine is the possessive determiner meaning “my”. In German, possessive determiners change their ending to agree with the gender, number, and case of the noun.

Schwester is feminine, singular.
In this sentence, Schwester is the subject, so it is in the nominative case.
Feminine nominative singular takes the ending -e, so mein → meine.

Some examples:

Mein Bruder (my brother) – Bruder is masculine nominative.
Meine Schwester (my sister) – Schwester is feminine nominative.
Mein Kind (my child) – Kind is neuter nominative.

Why is Schwester capitalized?

All nouns in German are capitalized, no matter where they appear in the sentence. Schwester is a noun (like sister), so it must start with a capital letter.

The same is true for Fitnessstudio and Woche in this sentence: they are nouns, so they are capitalized.

Why is the verb geht and not gehts or something else? How is it formed?

The infinitive is gehen (to go). For the subject meine Schwester, we conjugate it in the present tense, 3rd person singular:

ich gehe
du gehst
er / sie / es geht
wir gehen
ihr geht
sie gehen

Meine Schwester is like sie (she), so you use geht.

Why can the present tense geht mean “goes three times a week” as a regular habit?

German present tense (Präsens) is used both for:

Actions happening now
- Sie geht gerade ins Fitnessstudio. – She is going to the gym right now.
Regular, habitual actions
- Sie geht dreimal pro Woche ins Fitnessstudio. – She goes to the gym three times a week.

German does not need a special continuous form like English “is going”; context and time expressions (like dreimal pro Woche) show whether it’s a habit or something happening now.

Why is dreimal written as one word? Could I also say drei Mal?

In everyday German, dreimal (one word) is standard when you mean “three times” in the sense of frequency or repetition.

dreimal pro Woche – three times per week

You will also sometimes see drei Mal, especially when Mal is clearly used as a noun (“occurrence, time”):

Das erste Mal, das zweite Mal, das dritte Mal – the first/second/third time

For the frequency expression in your sentence, dreimal (one word) is the usual and simplest choice.

What does pro Woche literally mean, and can I say it in other ways?

Pro Woche literally means “per week”. It’s very similar to English in meaning and structure.

Other common alternatives:

dreimal die Woche – three times a week
dreimal in der Woche – three times in the week

All of these mean roughly the same in everyday speech:

Meine Schwester geht dreimal pro Woche ins Fitnessstudio.
Meine Schwester geht dreimal die Woche ins Fitnessstudio.
Meine Schwester geht dreimal in der Woche ins Fitnessstudio.

Pro Woche sounds a bit more neutral/formal; die Woche and in der Woche are very common in spoken language.

Why is it dreimal pro Woche and not dreimal pro Wochen? Why is Woche singular?

With pro in the sense of “per X”, German almost always uses the singular:

dreimal pro Woche – three times per week
zweimal pro Monat – twice per month
einmal pro Jahr – once per year

The idea is “per one week,” “per one month,” etc. So Woche stays singular.

Why does the sentence say ins Fitnessstudio and not just in Fitnessstudio?

In German, you normally cannot put a place-noun after a preposition without an article (unless it’s a special fixed expression). Here, Fitnessstudio is a neuter noun: das Fitnessstudio.

The preposition in + the article das contracts to ins:

in + das = ins
in das Fitnessstudio → ins Fitnessstudio

So ins Fitnessstudio literally means “into the gym”.

Why is ins Fitnessstudio using the accusative case? Doesn’t in sometimes take dative?

In is a “two-way” preposition: it can take accusative or dative depending on meaning:

Accusative = movement / direction (where to?)
Dative = location / position (where?)

In your sentence, your sister is going to the gym (movement, change of place), so accusative is used:

Sie geht ins Fitnessstudio. (Wohin? – Where to?) → in das → ins (accusative)
Sie ist im Fitnessstudio. (Wo? – Where?) → in dem → im (dative)

What is the difference between ins Fitnessstudio gehen and im Fitnessstudio sein?

ins Fitnessstudio gehen = to go to the gym (movement towards the gym)
im Fitnessstudio sein = to be at the gym / in the gym (location inside the gym)

Compare:

Meine Schwester geht dreimal pro Woche ins Fitnessstudio.
She goes there three times a week.
Meine Schwester ist gerade im Fitnessstudio.
She is at the gym right now.

Could I say zum Fitnessstudio instead of ins Fitnessstudio? Is there a difference?

Both are possible but slightly different in nuance:

ins Fitnessstudio gehen – emphasizes going inside the gym building.
zum Fitnessstudio gehen – literally “go to the gym,” focusing more on the destination as a point, not necessarily on entering inside (though usually implied in context).

In practice, for “going to the gym to work out,” ins Fitnessstudio gehen is very common and natural. Zum Fitnessstudio gehen is also understandable and can be used, especially if the focus is on the route or destination.

Why is the time phrase dreimal pro Woche placed before ins Fitnessstudio? Could I put it at the end?

German has a typical word-order pattern for adverbials: Time – Manner – Place. A very natural order is:

Meine Schwester geht [dreimal pro Woche] [ins Fitnessstudio].

You can move the time phrase, but the sentence will sound more or less natural depending on context and emphasis:

Meine Schwester geht dreimal pro Woche ins Fitnessstudio. (neutral, very natural)
Meine Schwester geht ins Fitnessstudio dreimal pro Woche. (possible; sounds a bit marked or afterthought-like)
Dreimal pro Woche geht meine Schwester ins Fitnessstudio. (emphasis on three times a week)

So the given sentence follows the most neutral, standard pattern.

Is there any difference between dreimal pro Woche and dreimal die Woche?

They are very close in meaning: both express frequency.

dreimal pro Woche – sounds a bit more neutral or “book-like,” similar to “three times per week.”
dreimal die Woche – very common in spoken German, similar to “three times a week.”

In everyday conversation, dreimal die Woche may actually be slightly more frequent, but dreimal pro Woche is also completely normal and correct.