मांसपेशी को धीरे स्ट्रेच कीजिए।

A word-by-word breakdown:

• मांसपेशी = muscle
• को = an object marker, roughly marking the muscle as the thing being acted on
• धीरे = slowly
• स्ट्रेच = stretch (borrowed from English)
• कीजिए = polite imperative of करना (to do), so here it helps form a polite instruction: please stretch

So the whole sentence means something like:

• Please stretch the muscle slowly.
• or Stretch the muscle slowly. in a polite/instructional tone

In Hindi, को often marks the object of a verb, especially when that object is specific or definite.

Here, मांसपेशी को means the speaker is referring to a particular muscle that should be stretched.

So:

• मांसपेशी को = the muscle / that muscle as the target of the action

In English, we do not need a special object marker, but Hindi often does.

Yes. मांसपेशी is singular: muscle.

This sentence may be talking about:

• one specific muscle
• one muscle group treated as a single target
• a generic instruction focused on one affected area

If you wanted muscles, you would usually say:

• मांसपेशियों को धीरे स्ट्रेच कीजिए।

So the singular here is not strange; it just depends on context.

Hindi often leaves out words like your, his, or her when the meaning is obvious from context.

In an exercise or medical instruction, it is already understood that the person should stretch their own muscle.

So Hindi can simply say:

• मांसपेशी को धीरे स्ट्रेच कीजिए।

If you wanted to be more explicit, you could say:

• अपनी मांसपेशी को धीरे स्ट्रेच कीजिए।
• अपनी मांसपेशियों को धीरे स्ट्रेच कीजिए।

English often prefers your, but Hindi does not always need it.

This is very common in modern Hindi, especially in:

• fitness
• medicine
• physiotherapy
• everyday urban speech

Hindi often borrows English action words and combines them with करना.

So:

• स्ट्रेच करना = to stretch
• स्ट्रेच कीजिए = please stretch

A more fully Hindi-style version could be something like:

• मांसपेशी को धीरे-धीरे खींचिए।

But स्ट्रेच कीजिए is perfectly natural in many real-life contexts.

कीजिए is a polite imperative form of करना (to do).

When Hindi uses borrowed English words like स्ट्रेच, it often makes the verb by adding करना:

• स्ट्रेच करना = to stretch
• स्ट्रेच कीजिए = please stretch / do a stretch

So कीजिए does not mean do in a separate literal sense here. It is just part of the normal Hindi way of turning स्ट्रेच into a usable verb phrase.

Because स्ट्रेच is a borrowed English word, Hindi usually does not attach regular Hindi verb endings directly to it.

Instead, Hindi uses the helper verb करना:

• स्ट्रेच करना
• स्ट्रेच कीजिए
• स्ट्रेच करो
• स्ट्रेच करें

This pattern is extremely common with English loanwords in Hindi.

Yes, कीजिए is polite and respectful. It is very suitable for:

• instructions
• advice
• a doctor or trainer speaking politely
• general written guidance

Less formal versions:

• मांसपेशी को धीरे स्ट्रेच करो। = informal singular
• मांसपेशी को धीरे स्ट्रेच करें। = polite/formal instruction style

So कीजिए gives the sentence a polite, instructional tone.

In Hindi, adverbs like धीरे usually come before the verb phrase.

So Hindi naturally says:

• मांसपेशी को धीरे स्ट्रेच कीजिए।

This matches the common Hindi pattern:

• object + adverb + verb

In English, we often say:

• Stretch the muscle slowly.

So the placement is different from English, but very normal for Hindi.

These are related, but not identical:

• धीरे = slowly
• धीरे-धीरे = slowly, gradually, little by little
• धीरे से = gently / softly

In an exercise context:

• धीरे स्ट्रेच कीजिए = stretch slowly
• धीरे-धीरे स्ट्रेच कीजिए = stretch gradually
• धीरे से स्ट्रेच कीजिए = stretch gently

So the sentence you have is natural, but other versions are also possible depending on the nuance.

Not in this sentence.

मांसपेशी is feminine, but कीजिए does not change here to match its gender. This is an imperative form, and the verb phrase stays the same.

So whether the object is masculine or feminine, you can still say:

• ...स्ट्रेच कीजिए

Gender would matter in other kinds of sentences more than it does here.

A simple pronunciation guide is:

maans-peshi ko dheere strech kee-jee-eh

A slightly more accurate transliteration:

mānspeśī ko dhīre sṭrech kījie

A few notes:

• मांसपेशी has a long aa sound at the start
• धीरे sounds roughly like dhee-reh
• कीजिए sounds roughly like kee-jee-eh
• स्ट्रेच is a Hindi spelling of English stretch

Yes. Depending on context, you might also hear:

• मांसपेशी को धीरे-धीरे खींचिए।
• मांसपेशी को धीरे से खींचिए।
• मांसपेशी को धीरे तानिए।

But in modern spoken Hindi, especially in fitness or therapy settings, स्ट्रेच कीजिए is very common and natural.

So the given sentence is not wrong or awkward; it just uses the modern mixed Hindi-English style that many speakers use.