Learn Hardcore Ukrainian: Вона хоче бути здоровою, тому щодня ходить у спортзал на тренування. - She wants to be healthy, so she goes to the gym for a workout every day.

здоровою is in the instrumental case and is very common after бути when talking about a state or condition someone is (or wants to be) in. It can feel a bit more like “to be (in a) healthy (state).”
здорова is in the nominative case and is more neutral, often used for simple descriptions:
- Вона здорова. – She is healthy.

In your sentence, бути здоровою sounds very natural and idiomatic for “to be healthy” as a desired condition.

What grammatical case is здоровою, and why does it look like that?

Здоровою is:

Case: Instrumental
Gender: Feminine
Number: Singular

It agrees with вона (she), which is feminine, and it comes from the adjective здоровий (healthy):

Masculine: здоровий → instrumental: здоровим
Feminine: здорова → instrumental: здоровою
Neuter: здорове → instrumental: здоровим

So we use здоровою to match вона and to fit the instrumental-case pattern after бути in this kind of “state” meaning.

What exactly does тому mean here, and how is it different from тому що?

In this sentence тому means “therefore / so / for that reason.” It introduces the result:

Вона хоче бути здоровою, тому щодня ходить у спортзал…
She wants to be healthy, therefore she goes to the gym every day…

By contrast:

тому що means “because” and introduces the reason:
- Вона щодня ходить у спортзал, тому що хоче бути здоровою.
  She goes to the gym every day because she wants to be healthy.

So:

тому = so / therefore (result)
тому що = because (cause)

Why is there a comma before тому?

There is a comma because we have two separate clauses:

Вона хоче бути здоровою – independent clause (She wants to be healthy)
тому щодня ходить у спортзал на тренування – independent clause showing the result (so she goes to the gym every day)

In Ukrainian, when clauses like this are linked in a cause → result relationship with тому, we usually put a comma between them:
…, тому …

Why is the verb ходить used instead of йде or піде?

Ukrainian has several verbs for “to go (on foot)” with different nuances:

ходити (here: ходить) – repeated, habitual, or multi-directional movement.
- Вона щодня ходить у спортзал. – She goes to the gym every day (regular habit).
йти (e.g. вона йде) – movement right now, in one direction.
- Вона зараз йде у спортзал. – She is going to the gym now.
піти (perfective) – to set off / go (once), focusing on the start of a single action.
- Вона піде у спортзал завтра. – She will go to the gym tomorrow (one time).

Since the sentence talks about something she does every day, ходить (habitual) is the correct and natural choice.

What case is спортзал in, and why does it look like the basic form?

Спортзал here is in the accusative singular after the preposition у and a verb of motion (ходить):

Preposition + motion: ходити у + accusative → у спортзал

For inanimate masculine nouns like спортзал, the accusative singular form is identical to the nominative singular:

Nominative: спортзал
Accusative: спортзал

So it looks like the basic form, but its grammatical role here is destination (accusative).

What is the difference between в спортзал, у спортзал, and до спортзалу?

в спортзал and у спортзал
- In modern Ukrainian they mean the same thing here: to the gym (inside it).
- The choice between в and у follows euphony (sound) rules: speakers choose whichever sounds smoother with surrounding consonants.
- After ходить, saying у спортзал flows nicely, so у is preferred in the example sentence.
до спортзалу
- Uses the preposition до
  - genitive (спортзалу).
- Literally “towards the gym / up to the gym.”
- Often used when the focus is on the direction/approach, not so much on entering and being inside.

In the sense of “She goes to the gym (as a place where she exercises),” в/у спортзал is the standard choice.

Is there any difference between у спортзал and у спортзалі?

Yes, they use different cases and mean different things:

у спортзал – accusative, direction “into the gym” (where she is going).
- Вона ходить у спортзал. – She goes to the gym.
у спортзалі – locative, position “in the gym” (where she is).
- Вона займається у спортзалі. – She works out in the gym.

Your sentence talks about where she goes, so у спортзал (accusative of direction) is correct.

Why do we say на тренування and not в тренування?

With activities, events, and organized sessions, Ukrainian commonly uses на + accusative:

йти на тренування – to go to (a) training/practice
йти на роботу – to go to work
йти на концерт – to go to a concert
йти на урок – to go to a lesson

So на тренування is the normal, idiomatic preposition + case combination here.

В тренування would sound wrong in this context; в is usually used with places (in/into a building, room, etc.), not for this kind of scheduled activity.

What exactly does щодня mean, and how is it different from кожного дня?

Both express the idea “every day”:

щодня – a single-word adverb meaning daily / every day.
- Вона щодня ходить у спортзал.
кожного дня – a phrase (genitive + noun) literally “of each day.”
- Вона ходить у спортзал кожного дня.

They are interchangeable in most contexts. Щодня is a bit shorter and slightly more “compact”; кожного дня sounds a touch more colloquial or explicit, but both are very common.

Is the word order щодня ходить у спортзал на тренування fixed, or can we move words around?

Ukrainian word order is relatively flexible. You can move adverbs and prepositional phrases to change emphasis:

Вона щодня ходить у спортзал на тренування. – neutral, standard.
Вона ходить щодня у спортзал на тренування. – more emphasis on ходить щодня (she goes every single day).
Щодня вона ходить у спортзал на тренування. – stronger emphasis on щодня at the start.

All of these are grammatically correct. The original order is the most neutral and typical.

Could we omit the pronoun вона in this sentence?

Yes, вона can be omitted:

Хоче бути здоровою, тому щодня ходить у спортзал на тренування.

Ukrainian is a pro-drop language: the verb ending -е in хоче / ходить already shows 3rd person singular, so the subject is clear from context.

Including вона is also fine. It can add slight emphasis on she (as opposed to someone else), or just sound a bit more explicit.

Why do we say хоче бути здоровою instead of just хоче здоровою?

The verb хотіти (“to want”) in Ukrainian normally takes an infinitive verb to express what someone wants to do or to be:

хотіти + infinitive
- Вона хоче бути здоровою. – She wants to be healthy.
- Вона хоче жити довго. – She wants to live long.
- Вона хоче працювати менше. – She wants to work less.

You cannot say *вона хоче здоровою; without бути it is ungrammatical. You need бути to link хоче with the adjective that describes the desired state.