Learn Hardcore Portuguese (Portugal): No fim do treino, sinto um alívio enorme e fico de ótimo humor, mesmo que fique calado por um momento. - At the end of the training, I feel huge relief and I’m in a great mood, even if I stay quiet for a moment.

No fim do treino = At the end of training / At the end of the practice
Very common, sounds completely natural.
No final do treino is also correct, but sounds slightly more formal or a bit heavier in everyday speech. You’d see final a lot in written language and more “careful” speech.

In many time expressions, fim is the default in everyday Portuguese:

no fim do dia – at the end of the day
no fim de semana – at the weekend (PT-PT)
no fim do mês – at the end of the month

So here No fim do treino is simply the most natural, conversational choice. Both would be understood; fim just feels more colloquial and idiomatic.

What exactly is happening in do treino? Why not just de o treino?

Do is a standard contraction:

de + o = do (masculine singular)
de + a = da
de + os = dos
de + as = das

So:

de o treino → do treino
literally of the training → of training / of the practice.

In correct Portuguese, you almost never keep de o separate; you must contract to do. The same applies with other prepositions, e.g.:

a + o = ao (vou ao treino – I’m going to training)
em + o = no (estou no treino – I’m at training)

Why is it sinto um alívio enorme instead of something like sinto-me aliviado? What’s the difference?

Both are correct, but they’re slightly different structures:

sinto um alívio enorme
- Literally: I feel a huge relief.
- sinto = I feel (transitive verb, taking an object)
- um alívio enorme = the thing you feel (a noun phrase).
sinto-me aliviado
- Literally: I feel relieved.
- sinto-me = I feel myself (reflexive)
- aliviado = an adjective describing me.

In practice:

sinto um alívio enorme focuses on the sensation of relief itself.
sinto-me aliviado focuses on my state (I am in a relieved state).

In your sentence, the emphasis is on the wave of relief that comes at the end of the training, so the noun um alívio enorme works very naturally.

Why is it um alívio enorme and not um enorme alívio? Can the adjective go before the noun?

Both orders are possible:

um alívio enorme
um enorme alívio

In Portuguese, the “default” is noun + adjective, so um alívio enorme sounds completely neutral and natural.

When an adjective moves before the noun:

It can sound a bit more emotional, expressive, or literary.
Sometimes the meaning can shift slightly (depending on the adjective), but here it doesn’t change much.

So:

um alívio enorme – plain, neutral: a huge relief
um enorme alívio – a bit more emphatic / expressive: such a huge relief

In everyday speech, um alívio enorme is very common.

What does ficar mean in fico de ótimo humor? Is it “stay” or “become”?

Ficar has several meanings. In this sentence it means “to end up / to become / to be left in a state”, not “to stay in a place”.

Some common uses:

Location – to be located / to stay:
- A escola fica perto de casa. – The school is (located) near home.
- Fico em casa hoje. – I’m staying at home today.
Change of state / result – to become, end up:
- Fico cansado depois do treino. – I get tired after training.
- Ela ficou feliz com as notícias. – She became happy / She was happy with the news.

Here:

fico de ótimo humor ≈ I end up in a great mood / I’m in a great mood (as a result).

So it’s resulting state: after training finishes, I’m in a great mood.

Why is it fico de ótimo humor and not fico com ótimo humor? What does de do here?

Both de ótimo humor and com ótimo humor can appear in Portuguese, but de bom/ótimo/péssimo humor is the standard idiomatic pattern for “in a good/bad mood”:

estar de bom humor / mau humor / ótimo humor
ficar de bom humor / mau humor / ótimo humor

Examples:

Ele está de bom humor hoje. – He’s in a good mood today.
Fico de mau humor quando tenho fome. – I get in a bad mood when I’m hungry.

Using com:

com bom humor often leans more toward “with good humour / in a good-humoured way” (how you do something), e.g.:
- Ela respondeu com bom humor. – She answered with good humour.

So:

de ótimo humor = describes your state/mood.
com bom humor often describes the manner of an action, though context can blur this.

In your sentence, de ótimo humor is the more idiomatic choice.

Why does mesmo que take fique (subjunctive) and not fico (normal present)?

Mesmo que is one of the expressions that normally triggers the subjunctive in Portuguese when it introduces a clause expressing concession, like:

mesmo que – even if / even though
embora – although
ainda que – even if / even though

These introduce something that is presented as hypothetical, uncertain, or contrasted with the main statement, so Portuguese uses the present subjunctive:

mesmo que fique calado – even if I stay silent
embora chova – although it rains / even if it rains

So:

fico → present indicative (I stay / I become)
fique → present subjunctive (that I stay / even if I stay)

Because of mesmo que, fique (subjunctive) is the correct form here.

Who is the subject of fique in mesmo que fique calado? There’s no eu written.

The subject is still “eu” (I), even though it isn’t written.

In Portuguese, the subject pronoun (eu, tu, ele…) is very often dropped, because the verb ending usually makes the subject clear.

sinto → only possible subject = eu (I)
fico → here, context tells us it’s also eu
fique → 1st person singular of present subjunctive

So the full, “spelled-out” version would be:

…e (eu) fico de ótimo humor, mesmo que (eu) fique calado por um momento.

Because the forms of the verb already indicate the person, eu is omitted to avoid repetition and keep the sentence natural.

What exactly does calado mean in fique calado? Is it the same as “quiet” or “silent”?

Calado is an adjective that basically means not speaking, silent, keeping your mouth shut.

Nuance:

calado = not talking (mouth is shut, you’re not speaking)
em silêncio / silencioso = silent/quiet, often referring more to sound level or atmosphere.

Examples:

Fica calado! – Be quiet! / Shut up! (don’t speak)
Ele ficou calado durante a reunião. – He didn’t say anything during the meeting.
A sala estava em silêncio. – The room was silent.

In your sentence, mesmo que fique calado por um momento suggests:
even if I don’t say anything / even if I’m not talking for a bit — focusing on not speaking, not on the room being silent.

Why is it calado and not calada? How does gender agreement work here?

Adjectives in Portuguese must agree in gender and number with the noun (or pronoun) they describe.

If the speaker is male: calado
- Eu fico calado. – I (male) stay silent.
If the speaker is female: calada
- Eu fico calada. – I (female) stay silent.

In your sentence, the form calado implies that the speaker is grammatically masculine. If a woman were speaking, she would naturally say:

No fim do treino, sinto um alívio enorme e fico de ótimo humor, mesmo que fique calada por um momento.

Why is it por um momento? Could I also say durante um momento or por um bocado?

Yes, you have options, but they’re not all identical in feel:

por um momento
- Very common. Means for a moment / for a short while.
- Neutral and idiomatic here.
durante um momento
- Also correct, a bit more literal: during a moment.
- Can sound slightly more formal or just more “spelled out”.
por um bocado (colloquial)
- For a while / for a bit.
- Usually suggests a little longer than just um momento, and is very informal.

In your sentence, por um momento fits perfectly: it gives the idea of a short pause in speaking.

Why is there a comma before mesmo que: …fico de ótimo humor, mesmo que fique calado…?

The comma marks the beginning of a subordinate clause introduced by mesmo que. That clause (mesmo que fique calado por um momento) adds a concession:

Main idea: fico de ótimo humor – I’m in a great mood.
Concessive clause: mesmo que fique calado por um momento – even if I stay silent for a moment.

In Portuguese, it’s normal (and usually required) to put a comma before conjunctions like:

mesmo que
embora
porque (in many cases)
quando, se, etc., when they introduce subordinate clauses, especially if the clause is long or clearly separate in meaning.

So the comma helps show that a new, dependent idea is starting.

Could I move No fim do treino to the end and say Sinto um alívio enorme… no fim do treino? Is that still correct?

Yes, that’s grammatically correct and understandable:

No fim do treino, sinto um alívio enorme…
Sinto um alívio enorme… no fim do treino.

The difference is mostly focus and rhythm:

At the beginning: No fim do treino,
- Sets the time frame first. Feels very natural and fluent, especially in writing or storytelling.
At the end:
- Sinto um alívio enorme no fim do treino.
- Focuses first on the feeling, then adds when it happens.

Both are valid. In this kind of sentence, starting with the time phrase (No fim do treino) is very natural and common in Portuguese.