Learn Hardcore Spanish (Spain): Mi hermano corre como loco en el parque.

Mi hermano corre como loco en el parque.
= My brother runs / is running like crazy in the park.
(Most naturally understood as a habit/habitual behavior.)
Mi hermano está corriendo como loco en el parque.
focuses more on right now, at this moment.

Both are grammatically correct. The original sentence sounds more like a general description of his usual behavior in the park.

What part of speech is loco here? Is it an adjective or a noun?

In corre como loco, loco is functioning like a noun (literally “like a madman / like a crazy person”).

As an adjective: un hombre loco = a crazy man
As a noun: un loco = a madman

Because it’s used without an article (como loco, not como un loco), it feels a bit more like a set, idiomatic expression: “runs like crazy” rather than “runs like a madman.”

Why is it loco and not loca?

The form matches the gender of the person (or the implied person):

Mi hermano → masculine → loco
Mi hermana → feminine → loca

So you would say:

Mi hermano corre como loco en el parque.
Mi hermana corre como loca en el parque.

Could I say como un loco instead of como loco? Is there any difference?

Yes, both are correct:

corre como loco
corre como un loco

The difference is subtle:

como loco feels a bit more idiomatic/colloquial, like saying “runs like crazy”.
como un loco highlights more the image of a crazed person, more literally “like a madman”.

In everyday speech, como loco is very common and sounds slightly lighter/more figurative.

Could I say corre loco instead of corre como loco?

You generally would not say corre loco in standard Spanish.

corre como loco = “he runs the way a crazy person would” / “he runs like crazy”
corre loco would sound odd or ungrammatical; it suggests “he runs crazy” as if loco were an adverb.

If you drop como, you need a different structure, for example:

Corre estando loco. (grammatical but strange and not what you want)
Corre muy loco. (very colloquial and sounds weird; not standard)

To express “runs like crazy”, stick with corre como loco (or como un loco).

Why do we say en el parque and not por el parque? What’s the difference?

Both are possible, but they mean slightly different things:

en el parque = in the park (location)
- He runs like crazy inside that place.
por el parque = around / through the park (movement within an area)
- He runs like crazy around the park / all over the park.

So:

Mi hermano corre como loco en el parque.
Focus: the park is the place where he runs like crazy.
Mi hermano corre como loco por el parque.
Focus: he runs around and through different parts of the park.

Why do we need el in el parque? Can I say en parque?

You normally must use the article with parque here:

✅ en el parque
❌ en parque (incorrect in standard Spanish)

In Spanish, most countable singular nouns take an article (or some determiner) in contexts where English might drop it. So:

en la escuela = at school
en el trabajo = at work
en el cine = at the cinema

You can omit the article in some fixed expressions (en casa, en clase, en prisión, etc.), but parque is not one of those.

Is the order Mi hermano corre como loco en el parque fixed, or can I move parts around?

The given order is the most natural:

Mi hermano corre como loco en el parque.

You can move elements, but it affects naturalness or emphasis:

En el parque, mi hermano corre como loco.
Grammatically fine; emphasizes “in the park”.
Mi hermano, en el parque, corre como loco.
Also possible, sounds a bit more dramatic or written.

Some orders are technically possible but sound odd in everyday speech, e.g.:

Mi hermano corre en el parque como loco. (understandable, but less smooth)

Stick to the original order for the most neutral, natural sentence.

Could I drop Mi hermano and just say Corre como loco en el parque?

Yes, if it’s clear from context who you are talking about.

Spanish often drops subject pronouns and even full noun subjects when they are understood. So:

If you’ve just been talking about your brother,
Corre como loco en el parque is perfectly natural.
If there is no context, Mi hermano helps identify who is running.

Why is it mi hermano and not mío hermano or el hermano mío?

Spanish has two types of possessive forms:

Short forms (before the noun):
- mi hermano (my brother)
- tu hermana (your sister)
- su padre (his/her/their father)
Long forms (after the noun):
- el hermano mío (my brother)
- una hermana tuya (a sister of yours)

In everyday speech, short forms before the noun are the default:

mi hermano corre… is the normal, neutral way.
el hermano mío corre… is grammatically fine but sounds more emphatic or stylistic, like “that brother of mine”.

Does mi change for gender like hermano/hermana, or only for number?

Mi does not change for gender, only for number:

mi hermano (my brother)
mi hermana (my sister)
mis hermanos (my brothers / my siblings)
mis hermanas (my sisters)

So you would say:

Mi hermano corre como loco en el parque.
Mi hermana corre como loca en el parque.
Mis hermanos corren como locos en el parque.
Mis hermanas corren como locas en el parque.

If I make it plural, how does the whole sentence change?

For more than one brother:

Mis hermanos corren como locos en el parque.
- mis (plural)
- hermanos (plural)
- corren (3rd person plural)
- locos (masculine plural, agreeing with hermanos)

For more than one sister:

Mis hermanas corren como locas en el parque.

Is loco here offensive, or is it just a casual expression?

In this sentence, corre como loco is a casual, figurative expression, roughly “runs like crazy” or “runs like mad”.

Used about someone you know and in the right tone, it usually isn’t offensive; it just means very intensely / wildly.
Calling someone un loco directly (e.g. Eres un loco) about their mental health could be offensive, depending on the context and tone.

In everyday talk in Spain, como loco is common and generally light-hearted, especially about behavior in a specific situation.

Can correr mean both “run” (for exercise) and “run” like “sprint around wildly”?

Yes. Correr is the general verb for “to run”:

Mi hermano corre cada mañana.
= He runs / goes running every morning (for exercise).
Mi hermano corre como loco en el parque.
= He runs wildly / frantically in the park.

The meaning becomes more specific from the context or added expressions like como loco, muy rápido, para entrenar, etc.

Why is como here without an accent, and how is it different from cómo?

como (no accent) here is a conjunction of comparison, meaning “like / as”:
- corre como loco = he runs like crazy.
cómo (with accent) is used in questions and exclamations, meaning “how”:
- ¿Cómo corre tu hermano? = How does your brother run?
- ¡Cómo corre tu hermano! = Wow, your brother runs so fast!

In the sentence Mi hermano corre como loco en el parque, it’s a comparison, so it does not take an accent.