Learn Hardcore Spanish (Latin America): Los niños practican con sus patines en el parque después de clase. - The children practice with their skates in the park after class.

If you drop the article and just say Niños practican…, it sounds incomplete or like a fragment (more like a heading than a full sentence). So Los niños is the natural subject form here.

What tense is practican, and why that form?

Practican is:

present tense
3rd person plural (they)
of the verb practicar (to practice)

So:

(ellos / ellas) practican = they practice

In Spanish, the present tense is used both for:

habitual actions: Los niños practican… = The kids practice… (regularly)
and things happening now: context decides

You normally don’t need están practicando unless you really want to emphasize right now, at this very moment.

Why is it practican con sus patines and not practican sus patines?

In Spanish, when you say you practice a sport or an activity using something, you typically use con (with):

practican con sus patines = they practice with their skates

If you said practican sus patines, it would sound like they practice their skates, which is incorrect. The direct object of practicar is usually an activity or skill, not the equipment:

practican patinaje = they practice skating
practican con sus patines = they practice (skating) with their skates

Why is sus used instead of los or ellos for “their skates”?

Sus is the possessive adjective for his / her / its / their in plural:

sus patines = his skates / her skates / their skates

It agrees with the noun it modifies (patines, plural) and not with the owner:

su patín (one skate)
sus patines (several skates)

You do not say los patines de ellos here unless you really want to stress “their, not someone else’s.”
Los patines alone would be the skates (no clear owner). Sus patines clearly means their skates in this context.

What exactly does patines mean, and is it always roller skates?

Patines is the plural of patín and can mean:

roller skates (quad skates)
inline skates (rollerblades)
ice skates (in some contexts)

In practice, in everyday Latin American Spanish, if you say:

patines with no context, people usually think of roller or inline skates, not ice skates (unless you’re clearly talking about ice).

Other related words:

patineta = skateboard
patinar = to skate

Why is it en el parque and not al parque?

en el parque = in the park / at the park (location)
al parque = to the park (movement, direction; contraction of a + el)

The sentence describes where the activity happens, not where they’re going:

Los niños practican con sus patines en el parque
→ The kids practice in/at the park.

If you wanted to say they are going to the park, you’d use al:

Los niños van al parque después de clase.
→ The kids go to the park after class.

Why is it después de clase and not después de la clase?

Both are grammatically correct, but they feel a bit different:

después de clase
- more general: after class (after classes are over, after the school day)
- very common in spoken language
después de la clase
- more specific: after a particular class (e.g., after math class)

In Latin American Spanish, después de clase is very natural when you mean “after school / after classes in general.”

Why do we need de in después de clase?

In Spanish, después is almost always followed by de when it introduces a noun:

después de la cena = after dinner
después del trabajo = after work
después de clase = after class

Without de, después is more adverb-like, meaning “later / afterwards,” not “after something”:

Te llamo después. = I’ll call you later / afterwards.

Here we’re saying “after class,” so we must use después de clase.

Can I move después de clase to the beginning of the sentence?

Yes. Spanish word order is flexible with time expressions. You can say:

Después de clase, los niños practican con sus patines en el parque.

This is completely correct and might even sound more natural in some contexts. It’s like starting with “After class, the kids practice…” in English.

Why is niños used and not something like hijos or chicos?

These words are close but not identical:

niños = children (age focus: kids, usually pre-teen)
chicos (or muchachos in many places) = kids/guys, more informal; can be older (teens, young adults)
hijos = sons / children specifically as someone’s kids (family relationship)

In this context we’re just talking about children as a group in a neutral way, so niños is the most straightforward choice.

If some are boys and some are girls, is niños still correct?

Yes. In standard Spanish:

a group of only boys → niños
a group of only girls → niñas
a mixed group (boys + girls) → grammatically niños (masculine plural is the default mixed form)

More explicitly inclusive options you might see or hear:

niños y niñas
niños, niñas y niñes (in some inclusive-language contexts)

But in traditional grammar, niños covers a mixed group.

Could I say Los niños están practicando con sus patines instead of practican?

Yes, but the nuance changes:

Los niños practican con sus patines…
→ general/habitual: The kids practice with their skates… (after class, as a routine)
Los niños están practicando con sus patines…
→ right now, at this moment: The kids are practicing with their skates…

With después de clase, we normally talk about what they regularly do, so the simple present practican is more natural.

Why does sus come before patines, not after like in English (skates their)?

In Spanish, possessive adjectives like mi, tu, su, nuestro, sus almost always come before the noun:

sus patines = their skates
nuestro coche = our car
mi casa = my house

You can put a possessive after the noun (los patines suyos) but that’s more emphatic or stylistic, and less common in everyday speech. For a normal sentence, sus patines is the standard order.