A postura correta protege contra lesões.

Because postura is a feminine noun in Portuguese.

• a = the, for feminine singular nouns
• o = the, for masculine singular nouns

So:

• a postura = the posture

This is something you usually have to learn with the noun. In Portuguese, grammatical gender is very important because articles and adjectives must agree with the noun.

Because correta has to agree with postura, which is feminine singular.

Agreement in Portuguese means the adjective changes form to match the noun:

• postura correta = correct posture
• movimento correto = correct movement

So here:

• postura = feminine singular
• correta = feminine singular adjective form

In Portuguese, adjectives often come after the noun.

So postura correta is the normal, natural order.

• postura correta = correct posture

If you put the adjective before the noun, it can sound more literary, emphatic, or less neutral in many cases. For everyday Portuguese, postura correta is the standard way to say it.

Protege is the third-person singular present tense of the verb proteger.

• proteger = to protect
• ele/ela protege = he/she protects
• você protege = you protect

In this sentence, the subject is A postura correta, which is grammatically singular, so the verb is singular too:

• A postura correta protege... = Correct posture protects...

Because the subject is still one thing: a postura correta.

Even though the idea is general, the noun phrase is singular, so Portuguese uses a singular verb:

• A postura correta protege
• not A postura correta protegem

This works like English Correct posture protects...

Contra means against.

So:

• proteger contra lesões = to protect against injuries

It shows what kind of danger or harm is being prevented.

This preposition is very common in Portuguese:

• vacina contra a gripe = vaccine against the flu
• proteção contra o sol = protection against the sun

Yes, proteger de also exists, and you may hear both proteger de and proteger contra.

But there is a slight difference in feel:

• proteger contra strongly emphasizes defense against something
• proteger de can also mean to protect from something

In a sentence like this, protege contra lesões sounds very natural and clear.

Because lesões is being used in a general sense here.

• contra lesões = against injuries in general

If you said contra as lesões, it would usually sound like you mean specific injuries already known in the context.

Compare:

• protege contra lesões = protects against injuries generally
• protege contra as lesões mais comuns = protects against the most common injuries

So leaving out the article is very normal here.

Because the idea is general: correct posture helps prevent injuries in general, not just one injury.

• lesão = injury
• lesões = injuries

Portuguese often uses the plural in this kind of broad statement, just like English does.

The singular is lesão.

• lesão = injury
• lesões = injuries

This is a common plural pattern in Portuguese:

• nouns ending in -ão often become -ões in the plural

Examples:

• lesão → lesões
• opinião → opiniões

But be careful: not every -ão noun follows the same pattern. Some become -ãos or -ães, so it is best to learn them individually.

In Brazilian Portuguese, protege is pronounced roughly like pro-TE-zhee.

A few useful points:

• the stress falls on te
• the g before e sounds like the s in measure or the zh sound
• the final e in Brazilian Portuguese is often pronounced like a light ee sound

So it does not sound like English protect.

Lesões can be approximated as leh-ZOYNS, but with a nasal ending.

Important details:

• stress is on the last syllable: -sões
• ões has a nasal sound, which is very common in Portuguese
• the final s in Brazilian Portuguese is often pronounced like s or z, depending on accent and sound environment

This nasal ending may feel difficult at first, so it helps to listen and repeat many words ending in -ões.

It is a general statement, even though it uses a.

Portuguese often uses the definite article with nouns when speaking about something in a general or class-level way.

So:

• A postura correta protege contra lesões.

means something like:

• Correct posture protects against injuries.

This is very natural in Portuguese. English often drops the article in this kind of general statement, but Portuguese frequently keeps it.

Usually, postura is better translated here as posture, not position.

• postura = posture, bearing, body alignment
• posição = position

In a health or fitness context, postura correta specifically means correct posture.

So position would usually not be the best choice in this sentence.

Yes, it sounds natural and standard.

It would fit well in contexts like:

• health advice
• fitness materials
• workplace safety guidance
• physical therapy or ergonomics

It is clear, grammatical, and idiomatic in Brazilian Portuguese.