Learn Hardcore Finnish: Jaksatko vielä mennä kuntosalille, vai oletko liian hengästynyt? - Do you still have the energy to go to the gym, or are you too out of breath?

jaksatko = do you still have the energy (for it)? / can you manage (it)?
voitko (from voida) = are you able / allowed to? (more neutral can)
pystytkö (from pystyä) = are you capable of it? (focus on ability / capability)

In this sentence:

Jaksatko vielä mennä kuntosalille…
= Do you still have enough energy to go to the gym…?

Using voitko or pystytkö would sound more like you’re asking about practical ability, not about tiredness or stamina:

Voitko vielä mennä kuntosalille? – Are you still able to go to the gym? (maybe schedule or permission)
Pystytkö vielä menemään kuntosalille? – Are you still capable of going to the gym? (could be physical limitation, but not as idiomatic for “are you too tired?”)

So jaksaa is the most natural here because the contrast is with liian hengästynyt (too out of breath, too exhausted).

What is the -ko in jaksatko and oletko, and why is it attached to the verb?

The -ko / -kö ending is the yes/no question clitic in Finnish.

It turns a statement into a question:
- Sinä jaksat. – You have the energy / you can manage.
- Jaksatko? – Do you have the energy?

It attaches to the first word of the clause, which is usually the verb in neutral yes/no questions:

Jaksatko vielä mennä…? – Do you still have the energy to go…?
Oletko liian hengästynyt? – Are you too out of breath?

If you want to emphasize some other element, you can attach -ko/-kö to that word instead:

Vieläkö jaksat mennä kuntosalille? – Do you still have the energy to go to the gym? (emphasis on “still”)
Kuntosalilleko sinä vielä jaksat mennä? – more like It’s to the gym that you still have the energy to go? (slightly surprised tone)

But the normal, neutral pattern is verb + -ko/kö.

Why is vielä placed before mennä, and what exactly does vielä mean here?

Vielä most often means still or yet. In this sentence:

Jaksatko vielä mennä kuntosalille…
= Do you still have the energy to go to the gym…?

Placing vielä before mennä links it to the whole action of going:

vielä mennä = still go / go yet

Word order is somewhat flexible, but the nuance changes slightly:

Jaksatko vielä mennä kuntosalille? (original)
Neutral: Do you still have the energy to go to the gym?
Vieläkö jaksat mennä kuntosalille?
Emphasizes vielä: Do you still (even now) have the energy…?

But the meaning of vielä here is “still (at this point in time)”, not “more” or “in addition”.

Why is it mennä kuntosalille and not mennä kuntosalissa or something else? What does -lle express?

Kuntosalille is the allative case (-lle ending), which usually means to, onto, towards a surface or place.

Roughly:

kuntosali – gym (basic form)
kuntosaliin – into the gym (illative, -in)
kuntosalille – to the gym (allative, -lle)
kuntosalissa – in the gym (inessive, -ssa)

With going to a place like a gym, bar, café, school etc., allative (-lle) is very common and idiomatic:

Menen kuntosalille. – I’m going to the gym.
Menen kirjastoon. – I’m going to the library. (here the illative is used instead; some places prefer -in, some -lle)

For kuntosali, Finns normally say mennä kuntosalille for “go to the gym”. Kuntosaliin is not impossible, but it sounds less natural in this everyday “going to work out” sense.

So in this context, kuntosalille = (to) the gym as a destination.

What is the difference between vai and tai, and why is vai used here?

Both vai and tai can be translated as or, but they are used in different situations.

vai is used in questions where you are asking the listener to choose between options:
- Jaksatko vielä mennä kuntosalille, vai oletko liian hengästynyt?
  = Can you still go to the gym, or are you too out of breath?
- You expect one of these to be true.
tai is used in statements and in open-ended questions where several options can be true at once, or you’re not forcing a single choice:
- Voit mennä uimaan tai kuntosalille. – You can go swimming or to the gym (or both, it’s just an option).

In yes/no type questions that offer alternative possibilities like this sentence, vai is the correct conjunction.

Why is it oletko liian hengästynyt and not something like liikaa hengästynyt? How does liian work here?

Liian means too (much) in the sense of excessive, more than is good/acceptable.

liian hengästynyt = too out of breath / too breathless
liian nopea = too fast
liian kallis = too expensive

Liikaa is the partitive form of liika (excess), and it usually modifies verbs or nouns, not adjectives:

Hän juo liikaa. – He/She drinks too much. (verb)
Siellä on liikaa ihmisiä. – There are too many people there. (noun)

So:

liian hengästynyt – correct: “too [adjective]”
liikaa hengästynyt – unnatural / incorrect; liikaa doesn’t normally modify adjectives this way.

That’s why the sentence uses liian hengästynyt.

What is hengästynyt grammatically? Is it an adjective or a verb form?

Hengästynyt is a past participle of the verb hengästyä (to get out of breath), but in practice it behaves just like an adjective.

As a verb form: it indicates a resulting state after an action.
As an adjective: it describes a person’s current condition.

In oletko liian hengästynyt?:

oletko – are you (verb olla)
liian hengästynyt – predicate adjective phrase: too out of breath

So grammatically it’s a participle, but you can think of it simply as an adjective: breathless / out of breath.

Why is there no sinä in the sentence? How do we know it’s “you”?

In Finnish, the personal pronoun is often dropped, because the verb ending already shows the person.

jaksatko – second person singular (you) because of -t
oletko – second person singular because of -t

So:

Sinä jaksat. – You have the energy.
Jaksat. – (You) have the energy.
Jaksatko? – Do you have the energy? (You)

Adding sinä makes it more emphatic or contrastive:

Sinäkö vielä jaksat mennä kuntosalille? – You still have the energy to go to the gym? (you, as opposed to others; surprised tone)

In neutral conversation, especially in questions like this, Finns normally leave sinä out.

How would I answer this question in Finnish if I want to say “Yes, I can still go” or “No, I’m too out of breath”?

Here are natural answers:

Positive / I can still go:

Joo, jaksan vielä mennä. – Yeah, I still have the energy to go.
Kyllä, jaksan vielä mennä kuntosalille. – Yes, I still have the energy to go to the gym.

Negative / I’m too out of breath:

En jaksa, olen liian hengästynyt. – I don’t have the energy, I’m too out of breath.
En, olen liian hengästynyt. – No, I’m too out of breath.

Note the negative:

en jaksa = I don’t have the energy / I can’t manage (1st person negative form of jaksaa).

Why is it mennä kuntosalille and not mennä kuntosalilleen or something with a possessive ending?

Kuntosalille here just means to the gym in general, not specifically your gym or their gym.

kuntosalille – to the gym (any gym; neutral, generic)
kuntosalilleen – to his/her/their own gym (with possessive suffix -nsa/-nsä)

In everyday speech about “going to the gym” as an activity, Finns just say:

Menen kuntosalille. – I’m going to the gym.

You’d only use something like kuntosalilleen if you really wanted to emphasize that it’s someone’s own personal gym, which is unusual in this generic question.

Is the word order “Jaksatko vielä mennä kuntosalille, vai oletko liian hengästynyt?” fixed, or can we move things around?

The basic word order is fairly flexible; Finnish uses word order partly for emphasis.

Some natural variants:

Jaksatko vielä mennä kuntosalille, vai oletko liian hengästynyt?
– Neutral, standard.
Vieläkö jaksat mennä kuntosalille, vai oletko liian hengästynyt?
– Emphasis on vielä (still): Do you still, even now, have the energy…?
Jaksatko mennä vielä kuntosalille, vai oletko liian hengästynyt?
– Slightly different rhythm; still understandable, but less common than (1) or (2).

However, you normally keep:

the question clitic -ko/kö attached to the first element of each clause (jaksatko, oletko), and
the conjunction vai between the two alternatives.

If you start moving vai or dropping -ko, it becomes unnatural or changes the structure.

Why isn’t “yhä” used instead of “vielä” for “still”? What’s the difference?

Both vielä and yhä can mean still, but:

vielä is the most common, neutral choice in everyday speech.
yhä is more formal, literary, or a bit stylistic.

You could say:

Jaksatko yhä mennä kuntosalille, vai oletko liian hengästynyt?

This is grammatically correct, but in normal spoken language vielä is much more natural. Yhä might appear in written texts, news, or more “elevated” style:

Tilanne on yhä vaikea. – The situation is still difficult.

For spoken, casual Finnish, stick with vielä here.

How would this sentence change if I were talking to more than one person (“you all”)?

For plural “you”, you change the verb endings to 2nd person plural:

te jaksatte – you (plural) have the energy
te olette – you (plural) are

The question forms:

Jaksatteko vielä mennä kuntosalille, vai oletteko liian hengästyneitä?

Notes:

jaksatteko – 2nd person plural question form
oletteko – 2nd person plural question form
liian hengästyneitä – plural partitive of hengästynyt because it describes multiple people.

Meaning: Do you (all) still have the energy to go to the gym, or are you (all) too out of breath?

Could I say “Jaksatko vielä kuntosaliin?” instead of “mennä kuntosalille”?

No, that would be ungrammatical/unnatural. You need a verb of motion before the place in the illative/allative case.

mennä kuntosalille – to go to the gym
tulla kuntosalille – to come to the gym

You can’t drop mennä and just say:

✗ Jaksatko vielä kuntosaliin?

That sounds like something is missing (Do you still have the energy to [what?] to the gym?). You must keep mennä (or another motion verb), because kuntosalille is only the destination, not the action.

Is this sentence considered formal, informal, or neutral? Would I say it to a friend?

The sentence is informal / neutral spoken style, mainly because:

it uses 2nd person singular (jaksatko, oletko)
there is no explicit sinä, which is typical in everyday speech
the vocabulary (kuntosalille, hengästynyt) is normal, casual language

You would certainly say this to:

a friend
a family member
a workout partner

In a formal context addressing someone politely in plural, you might instead use te-forms:

Jaksatteko vielä mennä kuntosalille, vai oletteko liian hengästyneet?

But the original sentence is perfectly natural for talking to one person you know.