M'escalfo abans de l'exercici.

M' is the clitic pronoun meaning myself / me here. The verb is being used reflexively: escalfar-se = to warm up.

• m' = em before a vowel
• escalfo = I warm up / I heat up

So:

• M'escalfo = I warm up
• full form before a consonant would be Em...
• before a vowel, em becomes m'

Example:

• Em vesteixo = I get dressed
• M'aixeco = I get up

Because Catalan often uses the verb reflexively when talking about warming oneself up.

There is a difference:

• escalfar = to heat/warm something
• escalfar-se = to warm up

So:

• Escalfo la sopa = I heat the soup
• M'escalfo abans de l'exercici = I warm up before exercise

Without the reflexive pronoun, the meaning would usually sound like you are warming something else, not yourself.

Escalfo is the 1st person singular present indicative form of escalfar.

That means it corresponds to I warm up / I am warming up, depending on context.

A few forms:

• jo escalfo
• tu escalfes
• ell/ella escalfa
• nosaltres escalfem
• vosaltres escalfeu
• ells/elles escalfen

In your sentence, the jo is not stated because Catalan usually leaves subject pronouns out unless needed for emphasis.

Grammatically, the Catalan present tense can cover both ideas, depending on context.

So M'escalfo abans de l'exercici can mean:

• I warm up before exercise = habitual/general
• I'm warming up before exercise = current action, if the situation makes that clear

Without extra context, many learners will understand it as a general habit.

If you want to make right now clearer, Catalan often uses:

• M'estic escalfant abans de l'exercici = I’m warming up before exercise

Abans de means before when it is followed by a noun or an infinitive.

Here it is followed by a noun phrase:

• l'exercici = the exercise

So:

• abans de l'exercici = before the exercise / before exercise

You often see:

• abans de + noun
• abans de + infinitive

Examples:

• abans de classe = before class
• abans de començar = before starting

By itself, abans usually means before / earlier in a more general sense:

• He arribat abans = I arrived earlier

Because the article here is l', not el.

Catalan contractions work like this:

• de + el = del
• de + els = dels

But with l', there is no special contraction:

• de + l'exercici = de l'exercici

So these are correct:

• del llibre = of the book
• de l'exercici = of the exercise / before the exercise in your phrase

You cannot say del exercici.

L' is the singular definite article, equivalent to the, used before a vowel sound.

The base forms are:

• el for many masculine singular nouns
• la for feminine singular nouns

But before a vowel, they often shorten:

• el exercici becomes l'exercici

So:

• l'exercici = the exercise

Other examples:

• l'amic = the friend
• l'aigua = the water

Yes, it could be plural, but the singular is very natural when speaking generically.

So abans de l'exercici can mean something like:

• before exercise
• before the workout
• before the exercise session

If you want to talk about multiple specific exercises, you could use the plural:

• abans dels exercicis = before the exercises

The singular here sounds like a general activity or session, not necessarily one single movement.

Yes, it is very common and natural.

A few common ways to express the idea are:

• escalfar-se = to warm up
• fer escalfament = to do a warm-up
• fer un escalfament = to do a warm-up session

Examples:

• M'escalfo abans de córrer = I warm up before running
• Faig escalfament abans d'entrenar = I do a warm-up before training

So your sentence is perfectly idiomatic.

A careful approximate pronunciation is:

muhs-kahl-fu ah-BANZ duh luhg-zur-SEE-see

A few useful notes:

• M' links directly to the next word
• escalfo has the stress on cal
• abans has the stress on the second syllable: a-BANS
• exercici has the stress on ci: e-xer-CI-ci

A more Catalan-like approximation:

• mes-KAL-fu a-BANS de lex-er-SI-si

One important detail: the final o in escalfo may sound more like u in many Eastern Catalan varieties, while other varieties may keep a clearer o sound.

Yes. Catalan word order is flexible, especially with adverbial phrases like abans de l'exercici.

Your sentence:

• M'escalfo abans de l'exercici

A very natural alternative:

• Abans de l'exercici, m'escalfo

Both are correct. The difference is mainly one of focus or style:

• M'escalfo abans de l'exercici = neutral statement
• Abans de l'exercici, m'escalfo = gives more emphasis to the time phrase

Yes, that is grammatically correct, but normally jo is omitted unless you want emphasis or contrast.

So:

• M'escalfo abans de l'exercici = the most natural neutral form
• Jo m'escalfo abans de l'exercici = I warm up before exercise, perhaps contrasting with someone else

Catalan often drops subject pronouns because the verb ending already shows the person.

So in most everyday situations, leaving out jo is the normal choice.