Learn Hardcore Croatian: Kad smo u dobroj formi, osjećamo se potpuno spremni za utakmicu. - When we are in good shape, we feel completely ready for the match.

The preposition u meaning in (location, not movement) normally takes the locative case.
The noun forma (shape, physical condition) is feminine singular. Its locative singular form is formi.
The adjective dobar (good) must agree with forma (feminine, singular, locative), so it becomes dobroj.

So:

nominative: dobra forma – a good shape/form
locative (after u = in): u dobroj formi – in (a) good shape

U dobra forma uses the wrong case (nominative instead of locative), so it’s ungrammatical here.

Why is there a comma after Kad smo u dobroj formi?

In Croatian, when a subordinate clause (introduced by kad = when) comes before the main clause, a comma is normally used to separate them.

Subordinate clause: Kad smo u dobroj formi
Main clause: osjećamo se potpuno spremni za utakmicu

So we write:

Kad smo u dobroj formi, osjećamo se…

If the order is reversed, the comma is usually not needed:

Osjećamo se potpuno spremni za utakmicu kad smo u dobroj formi.

What is the difference between kad and kada?

In this sentence, kad and kada mean the same thing: when.

kad – shorter, very common in speech and informal writing
kada – slightly more formal or neutral; also common

You can say:

Kad smo u dobroj formi, …
Kada smo u dobroj formi, …

Both are correct; the meaning doesn’t change here. It’s mostly a stylistic choice.

Why is smo used here? Can it be omitted like Kad u dobroj formi, osjećamo se…?

Smo is the 1st person plural form of biti (to be): mi smo = we are.

In Croatian, the present tense of biti is not usually dropped. You need it to form the correct verb phrase:

Kad smo u dobroj formi = When we are in good shape

Omitting smo (Kad u dobroj formi) sounds wrong/telegraphic in standard Croatian. Unlike subject pronouns (like mi) which are often omitted, the present form of biti is required here.

Why is it osjećamo se and not just osjećamo?

Because osjećati se is a reflexive verb meaning to feel (a certain way).

osjećati (without se) usually means to feel something (an object):
- Osjećamo bol. – We feel pain.
osjećati se (with se) means to feel intransitively, usually followed by an adjective:
- Osjećamo se spremni. – We feel ready.

In the sentence, we are describing how we feel, not what we feel, so the reflexive form osjećamo se is necessary.

Why is the verb osjećamo in the present tense, when the sentence describes a general situation?

Croatian commonly uses the present tense to express general truths, habits, or repeated situations, just like English does:

Kad smo u dobroj formi, osjećamo se potpuno spremni za utakmicu.
= Whenever / When(ever) we are in good shape, we feel completely ready for the match.

So this is the generic present, not just “right now”. It talks about what usually happens under those conditions.

Why is it potpuno spremni and not potpuno spremno?

The adjective must agree with the subject mi (we).

mi = 1st person plural → grammatically plural
default plural for a mixed or unknown-gender group is masculine plural
the predicate adjective spreman (ready) in masculine plural is spremni

So:

Mi smo spremni. – We are ready.
Osjećamo se potpuno spremni. – We feel completely ready.

Spremno is neuter singular, which would not agree with mi.

What if the group is all women? Would it still be spremni?

If the group is exclusively female, the adjective can be in feminine plural:

Mi (žene) smo spremne.
Osjećamo se potpuno spremne za utakmicu.

In practice:

Mixed group (men + women) → spremni (masculine plural)
Unknown / general “we” → usually spremni
Only women, explicitly female group → spremne is the most natural choice

Could I say Potpuno smo spremni za utakmicu instead of osjećamo se potpuno spremni za utakmicu?

Yes, but there is a nuance difference:

Osjećamo se potpuno spremni za utakmicu.
– Focus on the subjective feeling: we feel ready.
Potpuno smo spremni za utakmicu.
– Sounds more like an objective statement: we are (in fact) completely ready.

Both are grammatically correct. The original sentence emphasizes internal perception (how we feel).

Why is it za utakmicu and not na utakmicu?

Different prepositions express different relationships:

za + accusative → for (purpose, goal, in preparation for something)
- spremni za utakmicu – ready for the match
na + accusative → to (movement onto/into an event or surface)
- idemo na utakmicu – we’re going to the match

In this sentence, they are ready for the match (in terms of preparation), not going to the match, so za utakmicu is appropriate.

Why does utakmicu end in -u here?

Utakmica (match) is a feminine noun. Its cases (singular) are roughly:

Nominative: utakmica – the match (subject)
Genitive: utakmice
Dative: utakmici
Accusative: utakmicu
Vocative: utakmico
Locative: utakmici
Instrumental: utakmicom

After za, we use the accusative case, so we need utakmicu, not utakmica.

Can I change the word order to Osjećamo se potpuno spremni za utakmicu kad smo u dobroj formi?

Yes, that is perfectly grammatical.

Kad smo u dobroj formi, osjećamo se potpuno spremni za utakmicu.
Osjećamo se potpuno spremni za utakmicu kad smo u dobroj formi.

Both versions are natural. Croatian word order is relatively flexible, and both here express the same idea. The version with Kad… at the start slightly emphasizes the condition (being in good shape).