Nach der Arbeit trainiere ich zwanzig Minuten auf dem Laufband.

After work I train for twenty minutes on the treadmill.

Breakdown of Nach der Arbeit trainiere ich zwanzig Minuten auf dem Laufband.

• dem: the; (masculine or neuter, dative)
• ich: I
• die Arbeit: the work
• auf: on
• nach: after
• trainieren: to train
• zwanzig: twenty
• die Minute: the minute
• der: the; (feminine, dative)
• das Laufband: the treadmill

Questions & Answers about Nach der Arbeit trainiere ich zwanzig Minuten auf dem Laufband.

Why does the verb trainiere come before ich? I thought the word order was supposed to be “ich trainiere …”.

German main clauses follow the “verb in second position” rule (V2 rule). The finite verb must be in the second slot, not necessarily the second word.

In Nach der Arbeit trainiere ich zwanzig Minuten auf dem Laufband.

• Nach der Arbeit = one big element (a time phrase) in first position.
• trainiere = verb in second position.
• ich = subject, which then comes after the verb.

If you start the sentence with the subject instead, you get:

• Ich trainiere nach der Arbeit zwanzig Minuten auf dem Laufband.

Now ich is first, the verb trainiere is still second. Both versions are correct; the difference is just what you put in the first position for emphasis (time vs. subject).

Why is it nach der Arbeit and not nach die Arbeit?

Because the preposition nach always takes the dative case when it means “after” in a temporal sense.

• The noun Arbeit is feminine.
• Nominative: die Arbeit
• Dative (singular feminine): der Arbeit

So:

• nach + die Arbeit (wrong)
• nach + der Arbeit (correct)

That’s why the phrase has to be nach der Arbeit.

Why do we use trainiere here? Could I say something else like mache Sport or übe?

trainieren in German usually means to work out / train (physically) or practice as training. In this context, with Laufband (treadmill), it clearly means to work out.

You could say:

• Nach der Arbeit mache ich zwanzig Minuten Sport auf dem Laufband.
  (After work I do twenty minutes of sport on the treadmill.)

But üben is more like “to practice” a skill (piano, grammar, pronunciation), not typically for a workout on a treadmill.

So trainieren is the most natural verb for fitness training here.

In English we say “for twenty minutes”. Why is there no für in zwanzig Minuten?

German very often uses a bare time expression in the accusative to show duration, without any preposition:

• Ich trainiere zwanzig Minuten. = I train (for) twenty minutes.
• Ich schlafe acht Stunden. = I sleep (for) eight hours.
• Er bleibt eine Woche. = He stays (for) a week.

You can use für with time, but that usually adds a nuance of:

• limitation / emphasis:
  Ich bleibe nur für eine Woche. (only for one week)
• intention or contrast.

For a simple statement of how long something lasts, German normally leaves out für and just uses the accusative time expression:

• Ich trainiere zwanzig Minuten.
  (No für needed.)

Why is there no article before zwanzig Minuten? Why not die zwanzig Minuten?

With measure expressions like time, weight, and distance (when they indicate a general amount or duration), German usually drops the article:

• zwanzig Minuten (twenty minutes)
• zwei Stunden (two hours)
• drei Kilometer (three kilometers)

You would normally only use an article if you are talking about some specific or previously mentioned twenty minutes:

• Die zwanzig Minuten, die ich gestern trainiert habe, waren sehr anstrengend.
  (The twenty minutes that I trained yesterday were very exhausting.)

In your sentence, it’s just a general duration, so no article: zwanzig Minuten.

Why is it auf dem Laufband and not auf das Laufband?

Because here we are describing location, not movement toward a place.

In German, many two‑way prepositions (like auf, in, an, unter, etc.) take:

• Dative for location (where?),
• Accusative for direction (where to?).

Your sentence answers “Where do I train?” → location → dative:

• auf dem Laufband (on the treadmill) – dative.

If you were describing movement onto the treadmill, you would use accusative:

• Ich steige auf das Laufband.
  (I step onto the treadmill.)

Also, das Laufband (neuter) in the dative singular becomes dem Laufband:

• Nominative/Accusative: das Laufband
• Dative: dem Laufband

Hence: auf dem Laufband.

Could I say im Laufband or am Laufband instead of auf dem Laufband?

No, those would not be natural here.

• auf dem Laufband = on the treadmill (physically on top of it), which is what you do when running on it.
• im Laufband would literally be “in the treadmill” (inside the machine) – that doesn’t make sense for a person.
• am Laufband (an + dem) means “at the treadmill” and might be used, for example, if you are talking about standing/working at a conveyor belt in a factory, but not about running on a fitness treadmill.

For running/working out, auf dem Laufband is the standard expression.

Why is Laufband capitalized? And why are Arbeit and Minuten capitalized?

In German, all nouns are capitalized, regardless of whether they are common or proper nouns.

• Arbeit (work) – noun → capitalized.
• Minuten (minutes) – noun → capitalized.
• Laufband (treadmill) – noun → capitalized.

Articles and adjectives are not capitalized (unless they start the sentence), only the nouns themselves.

Why is the verb in the present tense (trainiere) if this is a regular habit? Wouldn’t German use something like “I used to / I will” train?

German Präsens (present tense) is very flexible. It can express:

1. An action happening right now:
   
   • Ich trainiere gerade. (I am training right now.)
2. A habitual/repeated action (like English “I work out after work”):
   
   • Nach der Arbeit trainiere ich zwanzig Minuten auf dem Laufband.
3. A near future (like English “I’m training after work”):
   
   • Nach der Arbeit trainiere ich.

German does not have a special tense like “I used to …” for habits; you use context or adverbs (e.g., früher, immer):

• Früher habe ich nach der Arbeit zwanzig Minuten auf dem Laufband trainiert.
  (I used to train …)

So the present trainiere here naturally expresses a recurring habit.

Can I change the word order, for example: Ich trainiere nach der Arbeit zwanzig Minuten auf dem Laufband? Is that still correct?

Yes, that’s correct. German word order inside the “middle field” (between the conjugated verb and the sentence‑final elements) is relatively flexible, though there are preferred patterns.

Some common variants:

1. Nach der Arbeit trainiere ich zwanzig Minuten auf dem Laufband.
   (Time phrase first, verb second, then subject.)

2. Ich trainiere nach der Arbeit zwanzig Minuten auf dem Laufband.
   (Subject first; neutral, very common.)

3. Ich trainiere zwanzig Minuten nach der Arbeit auf dem Laufband.
   (Puts more focus on the duration right after the verb.)

German often follows the heuristic TeKaMoLo for adverbials:

• Temporal (when?) – Kausal (why?) – Modal (how?) – Lokal (where?)

In your original sentence:

• Nach der Arbeit = temporal
• zwanzig Minuten = duration (also temporal, but closer to the verb)
• auf dem Laufband = local

So Nach der Arbeit trainiere ich zwanzig Minuten auf dem Laufband fits well with this tendency: time information earlier, place at the end.

What is the difference between nach der Arbeit and nachdem ich gearbeitet habe?

Both can express a similar time relation (“after I have worked”), but grammatically they are different:

• nach der Arbeit = preposition + noun (dative)
  Short, simple time phrase.
  Nach der Arbeit trainiere ich …

• nachdem ich gearbeitet habe = conjunction + full clause
  More complex; emphasizes the action “I have worked”.
  Nachdem ich gearbeitet habe, trainiere ich …

Often, nach der Arbeit focuses on the time period (“after work” as a block), while nachdem ich gearbeitet habe focuses on the action of working being completed.

In everyday speech for routines, nach der Arbeit is shorter and more common.

How is trainieren conjugated? Is it a regular verb?

trainieren is a regular (weak) verb in German. Its stem is trainier- in the present tense.

Present tense conjugation:

• ich trainiere
• du trainierst
• er/sie/es trainiert
• wir trainieren
• ihr trainiert
• sie/Sie trainieren

Perfect tense with haben:

• ich habe trainiert
• du hast trainiert, etc.

It is not a separable verb; there is no prefix that splits off. So you never say something like „*ich trainiere an“ or similar. The whole verb is just trainieren.