Learn Hardcore Norwegian: Treneren sier at god oppvarming kan hindre skade i skulderen. - The coach says that good warm‑up can prevent injury in the shoulder.

We add -en to many masculine/common-gender nouns to make them definite. Because the sentence is talking about a specific, known coach, Norwegian uses the definite form treneren.

What is the function of at in sier at god oppvarming kan hindre …?

Here at is a subordinating conjunction meaning “that” in English.

Treneren sier at … = The coach says that …

It introduces a subordinate clause (what the coach says):
at god oppvarming kan hindre skade i skulderen

Unlike English (where “that” can often be dropped), Norwegian is more likely to keep at:

English: The coach says (that) a good warm-up can prevent injury.
Norwegian: Treneren sier at god oppvarming kan hindre skade i skulderen.
(You normally do not drop at here in standard written language.)

Why is it god oppvarming and not godt oppvarming?

Adjectives in Norwegian agree with the gender and number of the noun.

oppvarming is a common-gender noun (en oppvarming)
The base form for adjectives with common gender singular is god

So:

en god oppvarming = a good warm-up
god oppvarming = good warm-up (indefinite, but with an adjective, we usually drop the article in this kind of general statement)

We would use godt (neuter) with a neuter noun:

et godt spill = a good game

So godt oppvarming is wrong because oppvarming is not neuter.

Why is oppvarming one word? Can I say å varme opp instead?

Yes, there is both:

å varme opp = to warm up (verb phrase)
en oppvarming = a warm-up / warming up (noun)

In the sentence, we need a noun (“good warm-up”), so oppvarming is correct.

Norwegian often turns verb + particle combinations into a single noun:

å varme opp → en oppvarming
å sette i gang → en igangsetting
å rydde opp → en opprydding

You cannot write opp varming as two words; as a noun it must be one: oppvarming.

Why is it kan hindre and not kan hindrer or kan å hindre?

kan is a modal verb (“can”), and in Norwegian:

A modal verb (kan, skal, vil, må, bør, osv.) is followed by the bare infinitive (no ending, no “å”).

So the pattern is:

kan + hindre

Not:

kan hindrer (wrong: two finite verbs together)
kan å hindre (wrong: no å after a modal)

Compare:

Jeg kan svømme. = I can swim.
De må gjøre leksene. = They must do the homework.
God oppvarming kan hindre skade. = Good warm-up can prevent injury.

Is skade here a noun or a verb?

In this sentence, skade is a noun meaning “injury” (or “damage”).

As a noun: (en) skade = an injury
As a verb: å skade = to injure / to harm

Clues that it’s a noun here:

It comes after the verb hindre (to prevent), which normally takes a noun as its object in this meaning:
- hindre skade = prevent injury
There is no å before skade, so it’s not an infinitive verb.

You could change it to the indefinite with article:

hindre en skade = prevent an injury (more specific/one injury) But in the original, skade is used in a general sense: injury (in general).

Why is there no article before skade (not en skade)?

Leaving out the article makes skade more general:

hindre skade ≈ prevent injury / prevent injury in general
hindre en skade ≈ prevent an (individual) injury

Norwegian often drops the article when talking about:

things in a general, non-countable way:
- forebygge sykdom = prevent disease
- unngå feil = avoid mistakes
- hindre skade = prevent injury

Using en skade would sound more like a specific, countable injury, not “injury” as a broad concept.

Why is it i skulderen and not i skulder?

skulderen is the definite form: “the shoulder”.

Forms:

en skulder = a shoulder
skulderen = the shoulder
skuldre / skuldrer = shoulders
skuldrene = the shoulders

Norwegian very often uses the definite form with body parts, especially when it’s clear whose body part it is:

Jeg har vondt i ryggen. = My back hurts.
Han brakk armen. = He broke his arm.
… kan hindre skade i skulderen. = can prevent injury in the shoulder.

You usually do not say i skulder.

Why is the preposition i used in i skulderen and not på skulderen?

Both i and på can appear with body parts, but they mean slightly different things:

i skulderen = in the shoulder (inside the joint / within the shoulder area)
på skulderen = on the shoulder (on the surface / resting on the shoulder)

Here we are talking about internal injury within the shoulder joint/area, so i skulderen fits best.

Examples:

Smerte i skulderen = pain in the shoulder
En fugl satt på skulderen hans. = A bird sat on his shoulder.

Could I say god oppvarming kan hindre skulderskade instead of skade i skulderen?

Yes, skulderskade is also a natural word in Norwegian.

skulderskade = shoulder injury (compound noun)
skade i skulderen = injury in the shoulder

They mean almost the same thing.
Subtle difference:

skulderskade sounds a bit more technical / compact, like a medical term or report.
skade i skulderen sounds slightly more descriptive / everyday.

Both are correct and commonly used.

Why is there no comma after Treneren sier?

Norwegian comma rules differ from English. You do not normally put a comma between the main verb and a direct object clause introduced by at.

Treneren sier at god oppvarming kan hindre skade i skulderen.

Here, the entire clause “at god oppvarming kan hindre skade i skulderen” is the object of sier.
No comma is needed (and a comma here would look wrong in modern Norwegian).

In contrast, commas before og, men, for can appear when they join two main clauses, but at-clauses used as objects do not get a comma in standard Bokmål today.

Could I move i skulderen earlier, like Treneren sier at god oppvarming i skulderen kan hindre skade?

Grammatically, you can move i skulderen, but the meaning shifts slightly and it may sound odd:

… at god oppvarming kan hindre skade i skulderen.
→ The injury is in the shoulder.
… at god oppvarming i skulderen kan hindre skade.
→ Sounds like the warm-up itself is located in the shoulder, which is a bit strange.

We normally think of oppvarming as something you do (exercises, movements), not as something that is “in the shoulder”. So the original word order is the natural one.